Tuesday, February 21, 2017
A unique study recently published in the authoritative Pediatric Nephrology medical journal shows that excess lipoproteins and fatty acids from high fat diets may be associated with the development of painful and often chronic kidney stones in children.
The breakthrough study, led by DMC's Children's Hospital of Michigan Urology Department Multidisciplinary Pediatric Stone Clinic Medical Director Larisa G. Kovacevic, MD, could have major implications for the diagnosis and treatment of a disorder that currently causes more than half a million emergency room visits in the United States each year. A growing percentage of kidney stone patients today are infants, children and teenagers, according to the latest data from the U.S. National Institute of Diabetes and Digestive and Kidney Diseases.
The newly published prospective controlled trial study (Marked Increase in Urinary Excretion of Apolipoproteins in Children with Nephrolithiasis Associated with Hypercalciuria) found that "abnormalities in lipid [fat] metabolism may play a role in kidney stone formation" -- and also noted that taking steps to identify such fat-metabolism problems in children "may have preventive and therapeutic benefits."
In order to reach that conclusion, the three-year study looked for the presence of a specialized group of "lipid metabolism and transport-related proteins" in 16 children with kidney stones, then compared the results with the levels of similar transport proteins in 14 children who were free of the stones.
The comparison revealed "a significant association between" a high level of lipid metabolism and transport-related proteins and pediatric kidney stones, according to Dr. Kovacevic.
"This is the first study to ever show that there is a marked increase in urinary excretion of these lipid metabolism and transport-related proteins in children with kidney stones," said Dr. Kovacevic, who led the Children's Hospital of Michigan Pediatric Urology Stone Clinic-based research team.
"This finding does suggest -- even though it's preliminary and based on data from only a small number of pediatric subjects -- that what we [pediatric clinicians] may need to do to provide better treatment for kids with kidney stones is to start checking their cholesterol and triglyceride blood levels . . . and if they are elevated, to then treat such patients accordingly by modifying their diets to reduce their intake of fat or providing effective medications, where appropriate."
Dr. Kovacevic said she is grateful for the funding she and her colleagues received from the Children's Hospital of Michigan Foundation, which made the study possible. She added that "these new findings are quite promising and we are excited about the implications for diagnosis and treatment of children with kidney stones."
Dr. Kovacevic also stated that the study was a "collaborative effort" of the Children's Hospital of Michigan Pediatric Stone Clinic and research team and acknowledged the help and support of Dr. Yegappan Lakshmanan, chief of Urology at the Children's Hospital of Michigan, and the major contributions of Dr. Hong Lu, Dr. Joseph A. Caruso and Dr. Ronald Thomas. Additionally, she recognized the continuous support of the entire Children's Hospital of Michigan Urology staff.
"The Children's Hospital of Michigan Pediatric Stone Clinic is unique in Michigan," she said, "because it takes a truly multidisciplinary approach to treating children with this problem. The team includes a nephrologist, a urologist, and a dietitian- which means that we can bring a wide variety of trained specialists to the crucial task of helping children who struggle with this disorder.
"Kidney stones are extremely painful, and they often recur. That means that these children miss school at times, along with other activities, and their parents often go through a great deal of stress and expense in caring for them."
Dr. Kovacevic, who has spent much of the past eight years as a clinical nephrologist specializing in diagnosing and treating kidney stone disorders in the Urology Department at the Children's Hospital of Michigan, said she hopes the just-published study in Pediatric Nephrology will help other researchers to achieve similar breakthroughs.
"As a pediatric kidney specialist who's been attending seminars and giving presentations about this condition all around the world in recent years, I'm greatly encouraged by these new findings," she said. "What we need now is to expand our research into the causes of this disorder and into devising better treatment tools for children with kidney stones.
"Additional new findings in this area could very well lead to new treatment options in which reducing fat intake, along with preventing childhood obesity and overweight, could become important goals in helping to lessen the impact of this often debilitating health condition."
The Children's Hospital of Michigan CEO Luanne Thomas Ewald, while congratulating Dr. Kovacevic and the Pediatric Kidney Stone Clinic on their breakthrough study, said it was "a compelling example of how clinical research can help to improve patient care, day in and day out, by helping to find new treatment modalities and new diagnostic methods.
"Our goal at the Children's Hospital of Michigan is to provide better outcomes for our patients, and this new publication in Pediatric Nephrology seems very likely to help accomplish that."
Physicians and patients like to believe that early detection of cancer extends life, and quality of life. If a cancer is present, you want to know early, right?
Not so fast.
An analysis of cancer screenings by a University of Virginia statistician and a researcher at the National Cancer Institute indicates that early diagnosis of a cancer does not necessarily result in a longer life than without an early diagnosis. And screenings - such as mammograms for breast cancer and prostate-specific antigen tests for prostate cancer - come with built-in risks, such as results mistakenly indicating the presence of cancer (false positives), as well as missed diagnoses (false negatives). Patients may undergo harsh treatments that diminish quality of life while not necessarily extending it.
Yet the benefits of early diagnosis through screening often are touted over the risks.
"It is difficult to estimate the effect of over-diagnosis, but the risk of over-diagnosis is a factor that should be considered," said Karen Kafadar, a UVA statistics professor and co-author of a study being presented Sunday at a session of the 2017 meeting of the American Association for the Advancement of Science. "How many diagnosed cases would never have materialized in a person's lifetime, and gone successfully untreated? Treatments sometimes can cause harm, and can shorten life or reduce quality of life."
Kafadar is not advocating against screening, but her findings show that frequent screening comes with its own risks. As a metric for evaluation, reduction in mortality is considered the standard. So if a disease results in 10 deaths per 100,000 people in a year, and screening reduces the deaths to six per 100,000 people, then there seems to be an impressive 40 percent reduction in mortality.
However, a more meaningful metric, Kafadar said, may be: "How much longer can a person whose case was screen-detected be expected to live, versus a case that was diagnosed only after clinical symptoms appeared?" This issue becomes harder to discern - how long a patient survives after a diagnosis versus how long the patient might have lived anyway. Some cancer cases might never become apparent during a person's lifetime without screening, but with screening might be treated unnecessarily, such as for a possibly non-aggressive cancer. And some aggressive forms of disease may shorten life even when caught early through screening.
Kafadar and her collaborator, National Cancer Institute statistician Philip Prorok, gathered long-term data from several study sources, including health insurance plans and the National Cancer Institute's recently completed long-term randomized control trial on prostate, lung, colorectal and ovarian cancer, to consider several factors affecting the value of screening - over-diagnosis, lead time on a diagnosis and other statistical distortions - to look at not just how many people die, but also life extension.
"People die anyway of various causes," Kafadar said, "but most individuals likely are more interested in, 'How much longer will I live?' Unfortunately, screening tests are not always accurate, but we like to believe they are."
Because the paper considers together the factors that affect statistical understanding of the effectiveness of screening, rather than looking at each of these factors in isolation as previous studies have done, it offers a new statistical methodology for teasing out the relative effects of cancer screening's benefits and risks.
Eating fish and seafood with higher levels of mercury may be linked to a higher risk of amyotrophic lateral sclerosis (ALS), according to a preliminary study released today that will be presented at the American Academy of Neurology's 69th Annual Meeting in Boston, April 22 to 28, 2017. However, fish and seafood consumption as a regular part of the diet was not associated with ALS.
"For most people, eating fish is part of a healthy diet," said study author Elijah Stommel, MD, PhD, of Dartmouth College in Hanover, N.H., and a Fellow of the American Academy of Neurology. "But questions remain about the possible impact of mercury in fish."
While the exact cause of ALS is unknown, some previous studies have suggested mercury to be a risk factor for the disease. In the United States, the primary source of exposure to mercury is through eating fish contaminated with the neurotoxic metal.
Often referred to as Lou Gehrig's disease, ALS is a progressive neurological disease that takes away the ability of nerve cells to interact with the body's muscles. Early symptoms of the disease can include muscle twitching and weakness in a limb. It typically develops into complete paralysis of the body, including the muscles needed to speak, eat and breathe. There is no cure for ALS, and eventually the disease is fatal.
For the study, researchers surveyed 518 people, 294 of whom had ALS, and 224 of whom didn't, on how much fish and seafood they ate. Participants reported the types of fish they ate, and whether they were purchased from stores or caught when they were fishing.
Researchers estimated the annual exposure to mercury by looking up the average mercury levels in the types of fish and the frequency that the participants reported eating them. Swordfish and shark are examples of fish that are considered high in mercury, while salmon and sardines typically have lower levels. Researchers also measured the levels of mercury found in toenail samples from participants with ALS and compared those levels to people without ALS.
The study found that among participants who ate fish and seafood regularly, those in the top 25 percent for estimated annual mercury intake were at double the risk for ALS compared to those with lower levels. A total of 61 percent of people with ALS were in the top 25 percent of estimated mercury intake, compared to 44 percent of people who did not have ALS. They also found that higher mercury levels measured in toenail clippings were associated with an increased risk of ALS. Those in the top 25 percent of mercury levels, based on fish-related intake or toenail clippings, were at a two-fold higher risk of ALS. These findings need to be replicated in additional studies.
The authors emphasize that this study does not negate the fact that eating fish provides many health benefits. However, the study suggests that the public may want to choose species that are known to have a lower mercury content, and avoid consuming fish caught in waters where mercury contamination is well-recognized. More research is needed before fish-consumption guidelines for neurodegenerative illness can be made.
Currently, U.S. Food and Drug Administration (FDA) health recommendations for women of childbearing age and children are to eat two to three weekly meals of species such as salmon or sardines that have low mercury, but are also high in nutrients such as potentially beneficial omega-3 fatty acids. The FDA recommends avoiding fish with the highest mercury levels, such as shark and swordfish. Check for waterbody-specific fish advisories when consuming fish caught by family or friends.
As mindfulness practices rise in popularity and evidence of their worth continues to accumulate, those who work with aging populations are looking to use the techniques to boost cognitive, emotional and physiological health.
But studies so far have shown mixed results in the elderly, and more investigation is needed to determine exactly how best to apply mindfulness in that population, a new review of the research to date has found.
A majority of the 27 studies in the review suggest that the focused attention at the core of mindfulness benefits older people, but others don't point to improvements. And that should prompt more rigorous investigations in search of interventions likely to do the most good, researchers from The Ohio State University found. Their analysis appears in the journal Frontiers in Aging Neuroscience.
"Mindfulness is a practice that really serves as a way to foster a greater quality of life and there's been some thought that it could help with cognitive decline as we age," said Stephanie Fountain-Zaragoza, lead author of the study and a graduate student in psychology.
"Given the growing interest in mindfulness in general, we wanted to determine what we know right now so that researchers can think about where we go from here," she said.
The good news so far: The evidence from a variety of studies points to some benefits for older adults, suggesting that mindfulness training might be integrated into senior centers and group homes, the researchers found.
Older people are an especially important population to study given diminished social support, physical limitations and changes in cognitive health, the researchers point out.
Studies of mindfulness meditation usually involve three types of practices. The first, focused attention, involves sustained attention to a single thing (such as the breath) and an effort to disengage from other distractions.
Open monitoring meditation, often seen as the next step up in mindfulness, includes acknowledging the details of multiple phenomena (sensations, sounds, etc.) without selectively focusing on one of them.
"This includes being open to experiencing thoughts and sensations and emotions and taking them as they come and letting them go," Fountain-Zaragoza said.
Loving-kindness meditation encourages a universal state of love and compassion toward oneself and others.
"The goal with this is to foster compassionate acceptance," said senior author Ruchika Shaurya Prakash, director of Ohio State's clinical neuroscience laboratory and an expert in mindfulness.
In addition to looking at how mindfulness contributed - or did not - to behavioral and cognitive functioning and to psychological wellbeing, some of the research also looked at its potential role in inflammation, which contributes to a variety of diseases.
In all categories of study, including inflammatory processes, Prakash and Fountain-Zaragoza found mixed results.
The hope is that mindfulness could help the elderly preserve attention and capitalize on emotional regulation strategies that naturally improve as we age, Prakash said.
"Around 50 percent of our lives, our minds are wandering and research from Harvard University has shown that the more your mind wanders, the less happy you are," she said.
"Mindfulness allows you to become aware of that chaotic mind-wandering and provides a safe space to just breathe."
In older people, mindfulness ideally has the potential to help with cognition, emotion and inflammation, but little research has been done so far and those studies that have been done have had mixed results and scientific limitations.
While most of the studies in the review showed positive results, the field is limited and would benefit greatly from larger randomized controlled trials, Fountain-Zaragoza said.
"We want to really be able to say that we have strong evidence that mindfulness is driving the changes we see," she said.
Thursday, February 16, 2017
Dr Jonathan Peake and Dr Oliver Neubauer, from QUT's Institute of Health and Biomedical Innovation, led a research review of studies about exercise and immunity.
They found the best way to avoid unfavourable changes in the immune system during a post-workout recovery was consuming carbs during or immediately after the exercise.
The paper was published in the Journal of Applied Physiology.
"There is intense interest in what athletes can do to recover faster from exercise," Dr Peake said.
"Among various nutritional strategies to counteract immune depression during exercise recovery, carbohydrates have proven the most effective. Ingesting carbohydrates during vigorous exercise may help, because carbohydrates maintain blood sugar levels.
"Having stable blood sugar levels reduces the body's stress response, which in turn, moderates any undesirable mobilisation of immune cells. However, more research is warranted to verify that this also helps to prevent infections and illnesses."
Dr Peake said exercise can increase and decrease the number of immune cells in blood.
But he said studies did not support the long-held belief that exercising regularly without allowing sufficient time for the immune system to return to normal increased the risk of a weakened immune system.
"People often have fewer natural killer white blood cells after a workout but we now believe they move to other parts of the body, rather than being destroyed.
"Exercise is a form of stress and more vigorous exercise creates more physiological stress which causes physiological and biochemical changes in the body. To tackle the potential threats these changes highlight, the immune cells may simply move out of the blood stream to the lungs, for example.
"This still leaves our bodies vulnerable to infections and, generally speaking, the more strenuous the exercise, the longer it takes for the immune system to return to normal.
"Epidemiological evidence suggests that regular moderate exercise protects against upper respiratory illnesses, like the common cold, whereas regular intense exercise increases the risk of upper respiratory illnesses."
Dr Neubauer said the research suggested most people only need carbohydrates during high-intensity or prolonged exercise of 90 minutes or more.
"The consumption of carbohydrates before and during strenuous exercise not only improves endurance performance, but it can also minimise exercise-related immune disturbances," he said.
"Between 30 and 60 grams of carbohydrates every hour during exercise help to support normal immune function. Examples of carbohydrates that could be consumed during exercise include carbohydrate-containing fluids, gels and bars consisting of different carbohydrates such as glucose and fructose. Alternatively, bananas may also do the job.
"As general advice for people who train for and participate in endurance events, any products should be tested if they are tolerated in the field.
"Consuming carbohydrates in the first few hours immediately after strenuous exercise also helps to restore immune function. This is especially important in situations where the recovery duration between two consecutive exercise sessions is short, which is often the case for athletes."
The researches did not find sufficient evidence to recommend 'immune-boosting' supplements, for example antioxidants.
"A diversified and well-balanced diet is most likely sufficient to help maintain immune function following longer-term exercise training.
"Sleep is recognised as important for maintaining immune function. However more research is needed to understand the influence of sleep on immunity in athletes."
A new study led by American Cancer Society researchers in collaboration with leading experts concludes that physical activity should be routinely assessed during the doctor-patient encounter, and that clinicians should design in collaboration with their patients a detailed physical activity plan with goals that should be set and monitored. The study uses concepts from public health and behavioral economics to provide practical advice to clinicians on effective counseling to patients.
The study appears early online in CA: A Cancer Journal for Clinicians. Below are highlights of the study:
- Despite abundant evidence linking physical inactivity to increased risk for numerous chronic conditions, such as some types of cancer, heart disease, type 2 diabetes, stroke, and even depression, physical inactivity is prevalent in modern society.
- In the United States, 51% of adults report not meeting aerobic physical activity guidelines, while objective measurement using accelerometers finds about 96.5% of adults ages 20 to 59 years do not meet those guidelines.
- The study, led by Kerem Shuval, PhD, and Tammy Leonard, PhD reports that because physicians' advice is respected and physician-patient encounters are frequent, these meetings can be used to provide consistent and comprehensive physical activity counseling, which may be an important vehicle for reducing the risk of chronic diseases and premature death.
- Physical activity should be routinely assessed at the clinic visit, a detailed physical activity plan should be jointly designed with the patient, and goals should be set and monitored.
- Specific strategies should be provided to patients to overcome impediments to activity. Both conscious and unconscious factors affect patients' behaviors and should be taken into account by the clinician and patient.
- Although the primary care setting is an important avenue to pursue physical activity promotion, it is not the only one. Policies aimed at changing the environment to one that is conducive to an active lifestyle are necessary to encourage sustainable changes.
What if you could lose weight and reduce your risk of life-threatening disease without any changes in what you eat -- other than a five-day special diet once every few months?
That's what happened for 71 adults who were placed on three cycles of a low-calorie, "fasting-mimicking" diet. The phase II trial, conducted by researchers at the USC Leonard Davis School of Gerontology, demonstrated a host of benefits from the regimen.
The diet reduced cardiovascular risk factors including blood pressure, signs of inflammation (measured by C-reactive protein levels), as well as fasting glucose and reduced levels of IGF-1, a hormone that affects metabolism. It also shrank waistlines and resulted in weight loss, both in total body fat and trunk fat, but not in muscle mass.
In effect, the diet reduced the study participants' risks for cancer, diabetes, heart disease and other age-related diseases, according to the findings published Feb. 15 in Science Translational Medicine.
"This study provides evidence that people can experience significant health benefits through a periodic, fasting-mimicking diet that is designed to act on the aging process," said Valter Longo, director of the USC Longevity Institute and a professor of biological sciences for USC Davis and Dornsife. "Prior studies have indicated a range of health benefits in mice, but this is the first randomized clinical trial with enough participants to demonstrate that the diet is feasible, effective and safe for humans.
"Larger FDA studies are necessary to confirm its effects on disease prevention and treatment," he added.
One hundred people participated in the trial from April 2013 to July 2015. The participants, ages 20 to 70 and all generally healthy, were divided into two groups for the randomized trial.
Participants in the first group, the control group, were asked to continue their normal eating habits for three months. People in the second group were placed on a three-month test of the fasting-mimicking diet.
Those on the special diet were required to eat food products supplied by the nutrition company L-Nutra during the fasting periods of five days each month. The diet, which was designed to mimic the results of a water-only fast, allowed for participants to consume between 750 and 1,100 calories per day. The meals for the fast-mimicking diet contained precise proportions of proteins, fats and carbohydrates.
After three months, participants in the control group were moved onto the special diet.
The researchers found that participants on the fasting-mimicking diet lost an average of about 6 pounds. Their waistlines shrank by 1 to 2 inches. Their systolic blood pressure, which was in the normal range when the study began, dropped by 4.5 mmHG, while their diastolic blood pressure dropped by 3.1 mmHg. Also, their levels of IGF-1 dropped to between 21.7 ng/mL and 46.2 ng/mL, reaching a range associated with lower cancer risk.
"After the first group completed their three months on the fasting diet, we moved over participants in the control group to see if they also would experience similar results," Longo said. "We saw similar outcomes, which provides further evidence that a fasting-mimicking diet has effects on many metabolic and disease markers. Our mouse studies using a similar fasting-mimicking diet indicate that these beneficial effects are caused by multi-system regeneration and rejuvenation in the body at the cellular and organ levels.
"Our participants retained those effects, even when they returned to their normal daily eating habits," he added.
The researchers also noted that participants considered "at risk" because they had risk factors such as high IGF-1, cholesterol, blood pressure or blood sugar levels, made significant progress toward better health.
For example, baseline fasting glucose levels for participants with high blood sugar levels (putting them at risk for diabetes) dropped into the healthy range, below 99 mg/dl -- but these levels didn't drop among participants who already had healthy levels at the beginning of the study. Cholesterol was reduced by 20 mg/dl in those with high cholesterol levels, and by about 5 mg/dl in all participants.
"Fasting seems to be the most beneficial for patients who have the great risk factors for disease, such as those who have high blood pressure or pre-diabetes or who are obese," Longo said.
The researchers had invited participants in the study for one last set of tests three months later, at the end of the diet. The research team found that the beneficial effects -- from weight loss, smaller waistlines and lower glucose, blood pressure and IGF-1 levels -- were sustained.
The next step for researchers is a large, FDA phase III clinical trial to test the FMD on patients diagnosed with age-related diseases or at high risk for them. The researchers said further investigation will determine whether the benefits of the diet can continue for several months.
Postmenopausal estrogen-based hormone therapy lasting longer than ten years was associated with a decreased risk of Alzheimer's disease in a large study carried out at the University of Eastern Finland.
"The protective effect of hormone therapy may depend on its timing: it may have cognitive benefits if initiated at the time of menopause when neurons are still healthy and responsive," says Bushra Imtiaz, MD, MPH, who presented the results in her doctoral thesis.
The study explored the association between postmenopausal hormone replacement therapy, Alzheimer's disease, dementia and cognition in two nation-wide case-control studies and two longitudinal cohort studies. The largest study comprised approximately 230,000 Finnish women and the follow-up time in different studies was up to 20 years.
Menopause may explain women's higher dementia risk
Alzheimer's disease is the most common cause of dementia, and two out of three Alzheimer's cases are women. One possible explanation for women's higher dementia risk is the postmenopausal depletion of sex steroid hormones estrogen and progesterone. Estrogen receptors are present throughout the body including brain areas primarily affected in Alzheimer's disease. In in vitro and animal studies, estrogen has showed neuroprotective effects. However, studies on humans have yielded inconsistent results on the association between postmenopausal estrogen-based hormone replacement therapy and dementia risk.
Hormonal therapy may protect cognition if started at the onset of menopause
In the present study, long-term use of hormonal replacement therapy was associated with a better performance in certain cognitive domains - global cognition and episodic memory - and a lower risk of Alzheimer's disease. Short-term use was not significantly linked to dementia risk, but in one cohort, dementia risk was higher among short-term users who had started hormone therapy in the late postmenopausal period. The results were adjusted for various lifestyle, socioeconomic and demographic variables.
"In the light of these findings, hormonal replacement therapy may have a beneficial effect on cognition if started early, around the time of menopause. The protective effect of hormonal therapy may depend on the health status of neurons at baseline and may be lost if therapy starts years after menopause," Dr Imtiaz concludes.
The study also showed that the postmenopausal removal of ovaries, uterus or both was not significantly linked to the risk of Alzheimer's disease, irrespective of the indication of surgery or hormone therapy use.
The research data was from the MEDALZ (Medication use and Alzheimer's disease), OSTPRE (Kuopio Osteoporosis Risk Factor and Prevention Study) and CAIDE (Cardiovascular Risk Factors, Aging and Dementia) studies. The newest results were published recently in Neurology and Maturitas and the earlier results in the Journal of Alzheimer's Disease.
A study by a joint research team including professor Kazuyo Tsuzuki of Toyohashi University of Technology, Department of Architecture and Civil Engineering, National Institute of Advanced Industrial Science and Technology and Asahi Kasei Homes revealed that airflow from an air conditioner (AC) stimulates the human body while sleeping and impacts on sleep conditions even if the mean airflow velocity is lower than an insensible level. It suggests some AC setting may have an unintentional negative impact on sleep quality despite the comfort the person feels.
Urban warming blocks the temperature at night from cooling. It causes sweltering nights and deteriorates sleep quality. However, high-quality sleep can still be realized if the room temperature is controlled effectively with an AC. The general belief is that having the AC on all night is bad for health. Also, quite a few of us experience chills while sleeping and awakening due to cold temperature.
Airflow velocity in the sleeping environment can be configured with the AC. However, no data on airflow velocity measurement or research on the influence of AC airflow have been available.
The research team, led by professor Kazuyo Tsuzuki, had the subjects sleep in two bedrooms set to the same temperature using ACs set at different airflow velocities, then made a comparison of the depth of sleep and body temperature control using electroencephalogram (EEG) measurements as well as subjective reporting by the subjects.
We call the air velocity of 0.2m/s or lower "insensible airflow", in a sense, the person remains unaware of such a low level of airflow. In this study, a comparison was made on the influence of two types of airflow, mean velocity of 0.14 m/s (general AC) and 0.04 m/s (customized AC), both at a room temperature of 26 °C. Subjects felt cooler with the higher airflow velocity during wakefulness and sleep. However, no significant difference was observed in the feeling of comfort, length of sleep depth, skin temperature, rectal temperature or sense of warmth or coolness in each subject before sleeping.
General AC lowers airflow when the room temperature reaches the desired setting and starts increasing the flow again when the temperature is higher. The study compared the correlation between the timing of the airflow starting to blow and body movement, heart rate and waking stage in sleep depth. The results found that the subjects have significantly greater body movements, an increased heart rate and a higher frequency of waking in the room that has the AC with a mean velocity of 0.14 m/s. This suggests the general AC may have some influence on sleep, as we discovered that subjects roll over or their sleep depth changes the moment cool air blows out.
This study was conducted using healthy adult male subjects. It implies that the cold airflow may have a greater impact on the overall sleep of female and elderly subjects with lower physical strength or a greater sensitivity to cold. The result of this study is expected to be a useful clue as to how to configure the airflow velocity of an AC to create a comfortable sleeping environment.
This research is the result of the study conducted by Professor Kazuyo Tsuzuki at the National Institute of Advanced Industrial Science and Technology.
The research results were reported online in the Energy and Buildings journal on December 23, 2016.
Recently, dietary guidelines for the general population have shifted towards a plant-based diet (rich in legumes, whole-grain cereals, fruits, vegetables and nuts) and low in animal-based foods (like red meat and pastries). Increasing evidence is suggesting that plant-based diets are beneficial for health and they also have less impact on the environment.
Researchers at the Unit of Human Nutrition of the Universitat Rovira i Virgili (Tarragona-Spain), in collaboration with other centers from the PREDIMED Study and Harvard University, have evaluated the associations between total and subtypes of fat intake and the risk of type 2 diabetes. In addition, they have evaluated the relationship between food sources rich in saturated fatty acids and the incidence of type 2 diabetes.
The research's main findings showed that those participants who consumed higher amounts of saturated fatty acids and animal fat had a twofold higher risk of developing type 2 diabetes than those participants with a lower intake of saturated and animal fat. The consumption of 12 grams per day of butter was associated with a twofold higher risk of diabetes after 4.5 years of follow-up, whereas the intake of whole-fat yogurt was associated with a lower risk. The present study analyzed data from 3,349 participants in the PREDIMED Study who were free of diabetes at baseline but at high cardiovascular risk. After 4.5 years of follow-up, 266 participants developed diabetes.
This study will be published in the scientific journal The American Journal of Clinical Nutrition in February 2017 and was led by doctors Marta Guasch-Ferré;, researcher at Harvard T.H. Chan School of Public Health, Nerea Becerra-Tomás, researcher at the URV's Unit of Human Nutrition, and Jordi Salas-Salvadó;, who is head of the URV's Unit of Human Nutrition, Clinical Director of Nutrition at the Internal Medicine Service of the Sant Joan University Hospital in Reus, principal investigator at the CIBERObn, and member of the Pere Virgili Health Research Institute (IISPV).
According to the researchers, these findings emphasize the healthy benefits of a Mediterranean diet for preventing chronic diseases, particularly type 2 diabetes, and the importance of substituting saturated and animal fats (especially red and processed meat) for those found in vegetable sources such as olive oil and nuts.
The global proliferation of overweight and obese people and people with type 2 diabetes is often associated with the consumption of saturated fats. Scientists at the German Diabetes Center (Deutsches Diabetes-Zentrum, DDZ) and the Helmholtz Center in Munich (HMGU) have found that even the one-off consumption of a greater amount of palm oil reduces the body's sensitivity to insulin and causes increased fat deposits as well as changes in the energy metabolism of the liver. The results of the study provide information on the earliest changes in the metabolism of the liver that in the long term lead to fatty liver disease in overweight persons as well as in those with type 2 diabetes.
In the current issue of the "Journal of Clinical Investigation", DZD researchers working at the German Diabetes Center, in conjunction with the Helmholtz Center in Munich and colleagues from Portugal, published a scientific investigation conducted on healthy, slim men, who were given at random a flavored palm oil drink or a glass of clear water in a control experiment. The palm oil drink contained a similar amount of saturated fat as two cheeseburgers with bacon and a large portion of French fries or two salami pizzas.
The scientists showed that this single high-fat meal sufficed to reduce the insulin action, e.g. cause insulin resistance and increase the fat content of the liver. In addition, changes in the energy balance of the liver were proven. The observed metabolic changes were similar to changes observed in persons with type 2 diabetes or non-alcoholic fatty liver disease (NAFLD). NAFLD is the most common liver disease in the industrial nations and associated with obesity, the so-called "metabolic syndrome," and is associated with an increased risk in developing type 2 diabetes. Furthermore, NAFLD in advanced stages can result in severe liver damage.
"The surprise was that a single dosage of palm oil has such a rapid and direct impact on the liver of a healthy person and that the amount of fat administered already triggered insulin resistance", explained Prof. Dr. Michael Roden, scientist, Managing Director and Chairman at the DDZ and the German Center for Diabetes Research (Deutsches Zentrum für Diabetesforschung, DZD). "A special feature of our study is that we monitored the liver metabolism of people with a predominantly non-invasive technology, e.g. by magnetic resonance spectroscopy. This allows us to track the storage of sugar and fat as well as the energy metabolism of the mitochondria (power plants of the cell)."
Thanks to the new methods of investigation, the scientists were able to verify that the intake of palm oil affects the metabolic activity of muscles, liver and fatty tissue. The induced insulin resistance leads to an increased new formation of sugar in the liver with a concomitant decreased sugar absorption in the skeletal muscles - a mechanism that makes the glucose level rise in persons afflicted with type 2 diabetes and its pre-stages. In addition, the insulin resistance of the fatty tissue causes an increased release of fats into the blood stream, which in turn continues to foster the insulin resistance. The increased availability of fat leads to an increased workload for the mitochondria, which can in the long term overtax these cellular power plants and contribute to the emergence of a liver disease.
The team of Prof. Roden suspects that healthy people, depending on genetic predisposition, can easily manage this direct impact of fatty food on the metabolism. The long-term consequences for regular eaters of such high-fat meals can be far more problematic, however.
Wednesday, February 15, 2017
People living in areas with winter snow may need to think twice before shovelling after a heavy snowstorm. According to a new study, snowfall is associated with a higher risk of hospital admission for heart attack, or myocardial infarction (MI), after heavy snowfall, especially in men. The study, published in CMAJ (Canadian Medical Association Journal), found associations with larger snowfalls and longer duration of snow.
"We suspect that shovelling was the main mechanism linking snowfall with MI," writes Dr. Nathalie Auger, University of Montreal Hospital Research Centre, Montréal, Quebec, with coauthors. "Men are potentially more likely than women to shovel, particularly after heavy snowfalls. Snow shovelling is a demanding cardiovascular exercise requiring more than 75% of the maximum heart rate, particularly with heavy loads."
A team of researchers looked at data from two separate administrative databases on 128 073 individual hospital admissions and 68 155 deaths from heart attack (MI) in the province of Quebec between 1981 and 2014. They restricted analysis to months in which snow falls, November to April, and obtained detailed weather information from Environment Canada for each health region included in the study.
About 60% of hospital admissions and deaths due to MI were in men. The day after a snowfall had the strongest association, with about 1/3 of MIs occurring then, and the association was even stronger after snowfalls lasting 2 to 3 days. These risks were elevated regardless of age, cardiovascular risk factors or other health conditions. However, the effects were not seen in women.
"Quantity of snowfall was associated with an increased likelihood of hospital admission or death due to MI the following day among men," write the authors. "The association between snowfall and MI was stronger among men, and weaker or absent among women."
The authors point out several limitations to the paper, including lack of data on sex-specific shovelling habits, size of areas shovelled or whether snow removal was manual or with a snow blower.
"Although these are potentially important considerations, the hypothesis that shovelling is associated with an increased risk of MI events among men remains plausible," they write.
The authors urge public awareness campaigns to educate people about the risk of heart attack after a snowfall and that they may need to avoid this activity depending on health status.
In a related commentary, Dr. David Alter, Toronto Rehabilitation Institute and the University of Toronto, writes the "findings add weight to our understanding that the act of snow shovelling in cold temperatures sets the stage for an eco-biological-behavioural 'perfect storm,' particularly among those physically deconditioned who have or who are at risk of heart disease."
Mediterranean diet rich in virgin olive oil may enhance the cardioprotective benefits of high-density lipoproteins (HDL--the "good" cholesterol) compared to other diets, according to new research in the American Heart Association's journal Circulation.
High levels of low-density lipoproteins (LDL--the "bad cholesterol") and triglycerides, a type of blood fat, are associated with an increased risk of heart and blood vessel diseases. HDL cholesterol is associated with a lower risk because these lipoproteins help eliminate the excess cholesterol from the bloodstream.
"However, studies have shown that HDL doesn't work as well in people at high risk for heart attacks, strokes and other cardiovascular diseases, and that the functional ability of HDL matters as much as its quantity," said senior study author Montserrat Fitó, M.D., Ph.D., and coordinator of the Cardiovascular Risk and Nutrition Research Group at the Hospital del Mar Medical Research Institute in Barcelona and at the Ciber of Physipathology of Obesity and Nutrition (CIBEROBN), Spain. "At the same time, small-scale trials have shown that consuming antioxidant-rich foods like virgin olive oil, tomatoes and berries improved HDL function in humans. We wanted to test those findings in a larger, controlled study."
Researchers randomly selected 296 people at high risk of cardiovascular disease participating in the PREDIMED (PREvención con DIeta MEDiterránea) study. Blood samples were taken from the participants at the beginning of the study and again at the end. Participants, average age 66, were randomly assigned to one of three diets for a year: a traditional Mediterranean diet enriched with virgin olive oil (about 4 tablespoons) each day, a traditional Mediterranean diet enriched with extra nuts (about a fistful) each day, or a healthy "control" diet that reduced consumption of red meat, processed food, high-fat dairy products and sweets. In addition to emphasizing fruit, vegetables, legumes, such as beans, chickpeas and lentils, and whole grains, both Mediterranean diets included moderate amounts of fish and poultry.
The study found that only the control diet reduced total and LDL cholesterol levels. None of the diets increased HDL levels significantly, but the Mediterranean diets did improve HDL function. The improvement in HDL function was much larger among those consuming an extra quantity of virgin olive oil.
Fitó and her team found that the Mediterranean diet enriched with virgin olive oil improved key HDL functions, including:
- Reverse cholesterol transport, the process by which HDL removes cholesterol from plaque in the arteries and transports it to the liver where it is used to produce hormonal compounds or eliminated from the body.
- Antioxidant protection, the ability of HDL to counteract the oxidation of LDL, which has been found to trigger the development of plaque in the arteries.
- Vasodilator capacity, which relaxes blood vessels, keeping them open and blood flowing.
Researchers said the differences in results between the diets were relatively small because the modifications of the Mediterranean diets were modest and the control diet was a healthy one. They added that study results are mainly focused on a high cardiovascular risk population that includes people who can obtain the most benefits from this diet intervention.
Still, Fitó said, "following a Mediterranean diet rich in virgin olive oil could protect our cardiovascular health in several ways, including making our 'good cholesterol' work in a more complete way."
Testosterone therapy provides protection against cardiovascular disease in men with low testosterone
(Boston)--Despite the continued controversy surrounding the use of testosterone in men who have testosterone deficiency (hypogonadism), a new study has found that long-term use of testosterone therapy not only improves vigor and vitality, but may reduce the risk of death due to cardiovascular (CV) disease.
These findings appear online in the Journal of Cardiovascular Pharmacology and Therapeutics.
Testosterone (T) is the primary male sex hormone. In men, T plays a key role in the development of male reproductive tissues as well as promoting secondary sexual characteristics such as increased muscle and bone mass and growth of body hair. In addition, T is essential for overall health and well-being and for the prevention of osteoporosis. Insufficient levels of circulating T in men, contributes to frailty and bone loss.
In the absence of large, prospective, placebo-controlled clinical trials of longer duration, substantial evidence regarding the safety and risk of testosterone therapy (TTh) with regard to cardiovascular outcomes can only be gleaned from observational studies. To date, there are limited studies comparing the effects of long-term TTh in hypogonadal men who were treated or remained untreated with T.
Researchers at Boston University Schools of Medicine (BUSM) and Public Health (BUSPH), along with researchers in Germany, established a registry to assess long-term effectiveness and safety of T in men. For this study, they sought to compare its effects on a host of parameters (obesity, cholesterol levels, diabetes, liver function) considered to contribute to cardiovascular disease.
The researchers followed a group of men for eight years who had been on TTh and compared them with another group of men who remained untreated for the same time period. They found there were only two deaths in the TTh group and neither was related to CV events. In the non-treated control group, there were 21 deaths, 19 of which were related to CV events. Furthermore, there were 26 non-fatal myocardial infarctions and 30 non-fatal strokes in the control group but none in the T-treated group.
According to the researchers, long-term TTh in men with hypogonadism appears to be an effective approach to achieve sustained improvements in cardiometabolic function and reduces the risk of CV events. "The low CV events observed in the T-group compared to the untreated (control) group strongly suggest that TTh is protective. We believe that the protective effect of T on the CV system provides clinicians with the opportunity to utilize this approach for secondary prevention for hypogonadal men with a history of CV events," explained corresponding author Abdulmaged M. Traish, PhD, professor of biochemistry and urology at BUSM.
People who eat a gluten-free diet may be at risk for increased exposure to arsenic and mercury - toxic metals that can lead to cardiovascular disease, cancer and neurological effects, according to a report in the journal Epidemiology.
Gluten-free diets have become popular in the U.S., although less than 1 percent of Americans have been diagnosed with celiac disease - an out-of-control immune response to gluten, a protein found in wheat, rye and barley.
A gluten-free diet is recommended for people with celiac disease, but others often say they prefer eating gluten-free because it reduces inflammation - a claim that has not been scientifically proven. In 2015, one-quarter of Americans reported eating gluten-free, a 67 percent increase from 2013.
Gluten-free products often contain rice flour as a substitute for wheat. Rice is known to bioaccumulate certain toxic metals, including arsenic and mercury from fertilizers, soil, or water, but little is known about the health effects of diets high in rice content.
Maria Argos, assistant professor of epidemiology in the UIC School of Public Health, and her colleagues looked at data from the National Health and Nutrition Examination Survey searching for a link between gluten-free diet and biomarkers of toxic metals in blood and urine.
They found 73 participants who reported eating a gluten-free diet among the 7,471 who completed the survey, between 2009 and 2014. Participants ranged in age from 6 to 80 years old.
People who reported eating gluten-free had higher concentrations of arsenic in their urine, and mercury in their blood, than those who did not. The arsenic levels were almost twice as high for people eating a gluten-free diet, and mercury levels were 70 percent higher.
"These results indicate that there could be unintended consequences of eating a gluten-free diet," Argos said. "But until we perform the studies to determine if there are corresponding health consequences that could be related to higher levels of exposure to arsenic and mercury by eating gluten-free, more research is needed before we can determine whether this diet poses a significant health risk."
"In Europe, there are regulations for food-based arsenic exposure, and perhaps that is something we here in the United States need to consider," Argos said. "We regulate levels of arsenic in water, but if rice flour consumption increases the risk for exposure to arsenic, it would make sense to regulate the metal in foods as well."
It's universally accepted that the benefits of exercise go well beyond fitness, from reducing the risk of disease to improving sleep and enhancing mood. Physical activity gives cognitive function a boost as well as fortifying memory and safeguarding thinking skills.
But can it enhance your vision? It appears so.
Intrigued by recent findings that neuron firing rates in the regions of mouse and fly brains associated with visual processing increase during physical activity, UC Santa Barbara psychologists Barry Giesbrecht and Tom Bullock wanted to know if the same might be true for the human brain.
To find out, they designed an experiment using behavioral measures and neuroimaging techniques to explore the ways in which brief bouts of physical exercise impact human performance and underlying neural activity. The researchers found that low-intensity exercise boosted activation in the visual cortex, the part of the cerebral cortex that plays an important role in processing visual information. Their results appear in the Journal of Cognitive Neuroscience.
"We show that the increased activation -- what we call arousal -- changes how information is represented, and it's much more selective," said co-author Giesbrecht, a professor in UCSB's Department of Psychological and Brain Sciences. "That's important to understand because how that information then gets used could potentially be different.
"There's an interesting cross-species link that shows these effects of arousal might have similar consequences for how visual information is processed," he continued. "That implies the evolution of something that might provide a competitive advantage in some way."
To investigate how exercise affects different aspects of cognitive function, the investigators enlisted 18 volunteers. Each of them wore a wireless heart rate monitor and an EEG (electroencephalogram) cap containing 64 scalp electrodes. While on a stationary bicycle, participants performed a simple orientation discrimination task using high-contrast stimuli composed of alternating black and white bars presented at one of nine spatial orientations. The tasks were performed while at rest and during bouts of both low- and high-intensity exercise.
The scientists then fed the recorded brain data into a computational model that allowed them to estimate the responses of the neurons in the visual cortex activated by the visual stimuli. They analyzed the responses while participants were at rest and then during low- and high-intensity exercise.
This approach allowed them to reconstruct what large populations of neurons in the visual cortex were doing in relation to each of the different stimulus orientations. The researchers were able to generate a "tuning curve," which estimates how well the neurons are representing the different stimulus orientations.
"We found that the peak response is enhanced during low-intensity exercise relative to rest and high-intensity exercise," said lead author Bullock, a postdoctoral researcher in UCSB's Attention Lab. "We also found that the curve narrows in, which suggests a reduction in bandwidth. Together, the increased gain and reduced bandwidth suggest that these neurons are becoming more sensitive to the stimuli presented during the low-intensity exercise condition relative to the other conditions."
Giesbrecht noted that they don't know the mechanism by which this is occurring. "There are some hints that it may be driven by specific neurotransmitters that increase global cortical excitability and that can account for the change in the gain and the increase in the peak response of these tuning profiles," he said.
From a broader perspective, this work underscores the importance of exercise. "In fact, the benefits of brief bouts of exercise might provide a better and more tractable way to influence information processing -- versus, say, brain training games or meditation -- and in a way that's not tied to a particular task," Giesbrecht concluded.
Recent research suggests that dietary fructose intake may increase serum uric acid concentrations and that both uric acid concentration and fructose consumption may be increased in individuals with non-alcoholic fatty liver disease (NAFLD). Investigators have now established that both dietary fructose consumption and serum uric acid concentrations are independently associated with non-alcoholic steatohepatitis (NASH). Their conclusions are published in the Journal of Hepatology.
NAFLD, the accumulation of extra fat in liver cells in people who drink little or no alcohol, is recognized as the fastest growing cause of liver disease in both Western and developing countries. It is estimated to affect up to 30% of the general population in Western countries and up to 9.6% of all children and 38% of obese children across a spectrum of liver disease, including NASH (defined as steatosis, hepatocyte ballooning and inflammation). Although NASH is a less aggressive form of NAFLD, it can progress to severe fibrosis and cirrhosis, with development of hepatocellular carcinoma in adults.
"It is plausible that dietary fructose intake and uric acid concentrations are potential risk factors for liver disease progression in NAFLD. Numerous studies have shown that high uric acid levels are associated with metabolic syndrome and NAFLD, but to date, to the best of our knowledge, no studies have tested the independence of associations among uric acid concentrations, fructose consumption, and NASH confirmed by biopsy," explained senior investigator Valerio Nobili, MD, Chief of the Hepatometabolic Unit Liver Diseases Laboratory, Bambino Gesù Hospital, IRCCS, Rome, Italy.
A team of researchers in Italy and the UK studied 271 obese children and adolescents with NAFLD (155 males, mean age 12.5 years) who underwent liver biopsy. All patients completed a food frequency questionnaire, indicating when specific foods were consumed (breakfast, morning snack, lunch, afternoon snack, dinner, etc.), how often (every day of the week, sometimes, or never), and portion size. Major sources of dietary fructose among children and adolescents are soda and other sweetened beverages. Nearly 90% reported drinking sodas and soft drinks one or more times a week. Almost 95% of patients regularly consumed morning and afternoon snacks consisting of crackers, pizza and salty food, biscuits, yogurt, or other snacks.
In the group of patients studied, 37.6% of patients had NASH and 47% of patients with NASH had high uric acid compared with 29.7% of patients who did not have NASH. Fructose consumption was independently associated with high uric acid, which occurred more frequently in patients with NASH than in not-NASH patients.
"In this study, we show for the first time that uric acid concentrations and dietary fructose consumption are independently and positively associated with NASH. The development of NASH may markedly affect life expectancy and quality of life in affected individuals and therefore it is crucial to understand the risk factors for NASH in children and adolescents in order to design effective interventions which can be used safely to treat this young group of patients," Dr. Nobili concluded.
Efforts geared towards behavior modification, nutrition education, and limiting access to soda and other sweetened beverages could potentially reduce fructose consumption in this particular population. Several countries have already launched campaigns to ban soda vending machines in schools.
A new study suggests that the melatonin content of dietary supplements often varies widely from what is listed on the label.
Results show that melatonin content did not meet within a 10-percent margin of the label claim in more than 71 percent of supplements, with the actual content ranging from 83 percent less to 478 percent more than the concentration declared on the label. The study also found that lot-to-lot variability within a particular product varied by as much as 465 percent.
"We found that some products have much more melatonin than is indicated on the label," said study co-author Praveen K. Saxena, PhD, professor in the department of plant agriculture and the Gosling Research Institute for Plant Preservation at the University of Guelph in Ontario, Canada. "Our findings reveal that further research is needed to clearly establish the stability and appropriate storage conditions to ensure safety, efficacy, and quality of melatonin products."
Study results are published in the Feb. 15 issue of the Journal of Clinical Sleep Medicine.
Melatonin is a natural hormone that helps regulate the daily cycle of sleep and wakefulness, with melatonin production increasing at night and decreasing in the morning. It also is widely available as a dietary supplement. Data from the National Center for Health Statistics of the National Institutes of Health show that the use of melatonin supplements by adults in the U.S. more than doubled from 0.6 percent in 2007 to 1.3 percent in 2012, with an estimated 3.065 million adults reporting that they had taken melatonin during the past 30 days.
Saxena and lead author Lauren A.E. Erland analyzed 31 supplements by ultraperformance liquid chromatography with electrochemical detection. All products were purchased from local grocery stores and pharmacies in Guelph, Ontario. Supplements spanned 16 different brands and included a representative sample of formulations, including liquids, capsules and chewable tablets.
Further analysis with mass spectrometry also found serotonin, a much more strictly controlled substance, in 26 percent of the tested supplements. According to the authors, the presence of unlabeled but significant quantities of serotonin could lead to serious side effects.
"Millions of people use melatonin for a variety of purposes, including as a sleep aid," said Erland. "It is important that clinicians and patients have confidence in the quality of supplements used in the treatment of sleep disorders."
Clinical guidelines published by the American Academy of Sleep Medicine recommend strategically timed melatonin as a treatment option for some circadian rhythm sleep-wake disorders, including jet lag disorder and shift work disorder. However, a new clinical practice guideline published by the AASM in the February issue of the Journal of Clinical Sleep Medicine suggests that clinicians not use melatonin as a treatment for sleep onset or sleep maintenance insomnia because the overall evidence available was weakly against melatonin's efficacy.
Because melatonin is classified as a dietary supplement, it is not subject to the same scrutiny as medications that are approved by the U.S. Food and Drug Administration. When comparing supplement labels, U.S. consumers should look for the "USP Verified" mark, which indicates that the formulation meets the requirements of the U.S. Pharmacopeial Convention.
It is important to talk to a doctor before taking melatonin as a dietary supplement. Help for an ongoing sleep problem is available from more than 2,500 sleep centers that are accredited by the American Academy of Sleep Medicine.
Researchers at the University of Birmingham have shown that increasing the levels of active vitamin D can help to optimise muscle strength in humans.
The team hope that the findings will inform the design of future supplementation studies, and begin to answer questions as to the optimal levels of vitamin D required for healthy muscles.
The study, published in PLOS ONE, builds on previous knowledge showing levels of inactive vitamin D to be associated with a lack of muscle mass.
The research is the result of a cutting edge technique that allowed both active and inactive forms of vitamin D to be assessed alongside their impact on various muscle functions.
Dr Zaki Hassan-Smith, from the University of Birmingham, explained, "We have a good understanding of how vitamin D helps bone strength, but we still need to learn more about how it works for muscles. When you look at significant challenges facing healthcare providers across the world, such as obesity and an ageing population, you can see how optimising muscle function is of great interest."
"Previous studies have tested for the inactive forms of vitamin D in the bloodstream, to measure vitamin D deficiency. Here, we were able to develop a new method of assessing multiple forms of vitamin D, alongside extensive testing of body composition, muscle function and muscle gene expression."
116 healthy volunteers, aged between 20-74, were recruited to the trial. Participants had both active and inactive levels of vitamin D measured alongside physical characteristics including body fat and 'lean mass', a measure of muscle bulk.
Women with a healthy body composition, and lower body fat, were less likely to have high levels of inactive vitamin D, a marker of vitamin D deficiency. This was echoed by the finding that levels of inactive vitamin D were lower in women with increased body fat. This would suggest a relationship between vitamin D and body composition.
However, the active form of vitamin D was not associated with body fat, but was associated with lean mass.
Individuals with an increased lean mass, and muscle bulk, had a higher level of active vitamin D in the bloodstream.
Dr Hassan Smith added, "By looking at multiple forms in the same study, we can say that it is a more complex relationship that previously thought. It may be that body fat is linked to increased levels of inactive vitamin D, but lean mass is the key for elevated levels of active vitamin D. It is vital to understand the complete picture, and the causal mechanisms at work, so we can learn how to supplement vitamin D intake to enhance muscle strength."
In this study some of the positive associations between active vitamin D and muscle bulk were not seen in men.
Future studies with larger cohorts will help to identify if this is due to biological differences. The team will now work alongside international collaborators to further investigate the mechanisms at work through lab-based studies and clinical trials.
Talk to a woman in menopause and you're likely to hear complaints about hot flashes and an inability to lose weight, especially belly fat. A new study shows how regular exercise can help reduce weight and control bothersome symptoms such as hot flashes, even in women who previously led sedentary lifestyles. The study outcomes are being published online today in Menopause, the journal of The North American Menopause Society (NAMS).
Decreased estrogen levels during the menopause transition often create an array of physical and mental health issues that detract from a woman's overall quality of life. The article "Improvements in health-related qualify of life, cardio-metabolic health, and fitness in postmenopausal women after a supervised, multicomponent, adapted exercise program in a suited health promotion intervention: a multigroup study" reports on 234 Spanish postmenopausal women aged 45 to 64 years who had at least 12 months of sedentary behavior and engaged in a supervised 20-week exercise program for the study. After the intervention, the participants experienced positive changes in short- and long-term physical and mental health, including significant improvements in their cardiovascular fitness and flexibility. In addition, they achieved modest but significant reductions in their weight and body mass index, and their hot flashes were effectively managed. This is especially good news for women who are reluctant to use hormones to manage their menopause symptoms and are looking for safe but effective nonpharmacologic options without adverse effects.
"Growing evidence indicates that an active lifestyle with regular exercise enhances health, quality of life, and fitness in postmenopausal women," says Dr. JoAnn Pinkerton, NAMS executive director. "Documented results have shown fewer hot flashes and improved mood and that, overall, women are feeling better while their health risks decrease."
Monday, February 13, 2017
Vitamin D is essential for strong bones and overall health, but the amount our bodies make from sunlight exposure and obtain from foods is not always enough, particularly for pregnant women.
U.S. Department of Agriculture (USDA) and University of California, Davis (UC Davis) scientists have found that a higher dose of vitamin D supplement during pregnancy may reduce inflammation. Their findings were published in the November 2016 issue of The Journal of Nutrition.
The research team included Charles Stephensen, with the USDA-Agricultural Research Service (ARS) Western Human Nutrition Research Center (WHNRC) in Davis, California; Melissa Zerofsky, a former UC Davis doctorate student; and Bryon Jacoby, a maternal fetal medicine specialist affiliated with UC Davis Medical Center. Researchers wanted to find out whether vitamin D intake levels should be higher than those common in prenatal supplements—400 international units (IU).
Severe vitamin D deficiency can contribute to osteoporosis in adults and rickets (a condition of weakened bones) in infants and children. Recent surveys also suggest that vitamin D deficiency affects up to 69 percent of American pregnant women.
Higher vitamin D levels in a person's blood may protect against certain types of cancer, strengthen the immune system, reduce diabetes risk, and play a key role in suppressing inflammation. Reducing inflammation during pregnancy is important because inflammation is associated with high blood pressure, pre-eclampsia, premature delivery and low birthweight, according to Stephensen, research leader at WHNRC's Immunity and Disease Prevention Research Unit.
In the ARS-UC Davis study, healthy women in their first trimester of pregnancy voluntarily consumed different doses of vitamin D daily. They took either a multivitamin supplement containing 400 IU vitamin D and a placebo pill, or a 400 IU vitamin D supplement and an additional 1600 IU vitamin D pill. Blood samples were analyzed for various forms of vitamin D and immune and inflammatory markers. The mothers' blood pressure and infants' birthweight were recorded.
The vitamin D dosage did not affect maternal blood pressure or infant birthweight. However, the higher daily dose, 2000 IU vitamin D, increased circulating vitamin D concentrations relative to the 400 IU per day. Higher blood vitamin D was correlated with lower circulating tumor necrosis factor-α (TNF-α), an immune substance typically associated with inflammation.
The scientists concluded that consuming 2000 IU vitamin D instead of 400 IU each day is more effective at increasing vitamin D status in pregnant women. They also found that higher levels of vitamin D increased the proportion of a specific subset of immune cells with anti-inflammatory properties that may prevent adverse effects of excess inflammation.
As cold and flu season nears, now is a good time to take stock of zinc intake, because adequate zinc is essential to immune response. In a study funded by the U.S. Department of Agriculture's (USDA) Agricultural Research Service (ARS), a group of older adults with relatively low blood zinc concentrations boosted their immune function by raising their zinc levels.
Researchers observed an increase in T cells in blood that was challenged with a stimulus that mimicked infectious agents. T cells are white blood cells that play a key immune role. The researchers noted that the greater the blood zinc concentrations, the greater the increase in T cells.
The study was led by Simin Nikbin Meydani, director of the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University in Boston, Massachusetts.
For the study, researchers recruited participants 65 or older from Boston-area nursing facilities. More than 30 percent of the participants tested low in zinc. Researchers divided the zinc-deficient participants into two groups. For three months, one group consumed 30 milligrams (mg) of additional zinc via a daily multivitamin supplement, and a control group received a similar supplement that contained 5 mg of zinc. While the recommended dietary intake is 8-11 mg daily, the higher level was used because many volunteers had low blood zinc levels.
The researchers then retested the participants' blood zinc levels and T cell numbers. They found that the participants who took 30 mg of supplemental zinc had higher blood zinc concentrations and higher T-cell counts as well as better T-cell function than those in the control group.
Good sources of zinc include oysters and other shellfish, fortified breakfast cereals, beef, pork and beans. A personalized nutrient-intake assessment that includes a zinc-intake audit is available at www.supertracker.usda.gov.
Friday, February 10, 2017
What are some ways you cope with stresses in your life? Do you do yoga? Meditate? Exercise? Perhaps you should add taking prebiotics to that list.
Probiotics are well known to benefit digestive health, but prebiotics are less well understood. Prebiotics are certain types of non-digestible fibers that probiotic bacteria feed on, such as the fibers found in many plant sources like asparagus, oatmeal, and legumes. Certain bacteria also feed on non-fibers such as the protein lactoferrin, which also acts like a prebiotic and is found in breast milk.
According to a new study published in the online journal, Frontiers in Behavioral Neuroscience by Professor Monika Fleshner, PhD, and her team from the University of Colorado, Boulder, regular intake of prebiotics may promote beneficial gut bacteria and recovery of normal sleep patterns after a stressful episode.
"Acute stress can disrupt the gut microbiome," explained Dr. Agnieszka Mika, a postdoctoral fellow and one of the authors of the study, "and we wanted to test if a diet rich in prebiotics would increase beneficial bacteria as well as protect gut microbes from stress-induced disruptions. We also wanted to look at the effects of prebiotics on the recovery of normal sleep patterns, since they tend to be disrupted after stressful events."
In this experiment, test rats received prebiotic diets for several weeks prior to a stressful test condition and compared with control rats that did not receive the prebiotic-enriched diet. Interestingly, rats that ate prebiotics prior to the stressful event did not experience stress-induced disruption in their gut microbiota, and also recovered healthier sleep patterns sooner than controls.
Given that these experiments were done in rats, are these results relevant for humans? "The stressor the rats received was the equivalent of a single intense acute stressful episode for humans, such as a car accident or the death of a loved one," said Dr. Robert S. Thompson, the lead author of the study. "A next set of studies will be looking exactly at that question - can prebiotics help humans to protect and restore their gut microflora and recover normal sleep patterns after a traumatic event?"
In the mean time, should we start including prebiotics in our diets to help cope with stress? "So far no adverse effects from prebiotics have been reported," said Dr. Mika, "and they are found widely in many plants, even present in breast milk, and are already commercially available." Healthy gut bacteria and restful sleep could be your benefits.
Thursday, February 9, 2017
Nearly one in four adults aged 65 and older has trouble walking or climbing stairs--and 3.4 million older adults have trouble taking care of their personal needs, such as dressing or bathing. As we age, these difficulties can impact our well-being and our ability to live independently.
Based on the proven health benefits of exercise for older adults, a team of researchers theorized that exercise might also help adults prevent or delay disabilities that interfere with independent living. The team designed a study to test that theory, and their results were published in the Journal of the American Geriatrics Society.
The researchers enrolled 1,635 adults between the ages of 70 and 89. All of the participants were at high-risk for becoming physically disabled. At the beginning of the study, the participants were able to walk about five city blocks (one-quarter of a mile) without assistance. The participants were split into two groups. One group was encouraged to exercise regularly. In addition to taking a daily 30-minute walk, they performed balance training and muscle strengthening exercises. The other group attended weekly workshops for 26 weeks, followed by monthly sessions. The workshops provided information about accessing the healthcare system, traveling safely, getting health screenings, and finding reliable sources for health and nutrition education. The workshop instructors also led the participants in 5- to 10-minute flexibility or stretching exercise sessions.
Researchers gave all participants thorough tests for disability at the beginning of the study and then at 6, 12, 24, and 36 months after the study started.
The researchers reported that people in both groups experienced about the same level of disability after the study. However, people in the exercise group experienced a lower level of severe mobility problems than did people who attended the health workshops.
University of Rochester Medical Center scientists have discovered new essential information about omega 3 fatty acids contained in fish oil and how they could be used for asthma patients.
In a paper published in the Journal of Clinical Investigation--Insight, researchers using cell cultures from local asthma patients, found that:
• Omega-3 fatty acid products can reduce the production of IgE, the antibodies that cause allergic reactions and asthma symptoms in people with milder cases of asthma;• But in patients with severe asthma who use high doses of oral steroids, the omega-3 fatty acids are less effective because the corticosteroids block the beneficial effects.
Lead author Richard P. Phipps, Ph.D., the Wright Family Research Professor of Environmental Medicine, and his lab had previously shown that certain fatty acids contained in fish oil regulate the function of immune cells (B cells). They wanted to further investigate the effects on asthma.
People with asthma have an imbalance between molecules that dampen inflammation and those that increase inflammation. Using steroids as treatment controls the inflammation and relieves symptoms, but does not cure the underlying disease.
Phipps and his team collected blood from 17 patients at UR Medicine's Mary Parkes Asthma Center and isolated their B immune cells in the laboratory to explore the impact of pure omega-3-derived products on IgE and other molecules that fuel the disease. Co-authors Nina Kim, Ph.D., and Patricia Sime, M.D., the C. Jane and C. Robert Distinguished Chair in Pulmonary Medicine, conducted much of the laboratory and clinical work, and compared the results of the 17 patients to donors of healthy blood cells.
Most of the patients who volunteered for the study were taking corticosteroids in either pill form or by inhaler, depending upon severity of their asthma. Results showed that all responded to the omega-3 fatty acids to some degree, as evidenced by a reduction in the levels of IgE antibodies. But unexpectedly, Phipps said, the cells from a small subset of patients who were taking oral steroids were less sensitive to the omega-3 treatment.
Steroids are usually a very effective treatment for asthma. However, although the science is in the early stages, it appears that when corticosteroids are used steadily, in some cases the steroids reduce some of the body's natural ability to fight asthma-related inflammation, Phipps said.
The URMC discovery coincides with a New England Journal of Medicine study in late December 2016, showing that prenatal exposure to fish oil reduced the risk of wheeze and asthma in children. Phipps noted that the fish oil used as a dietary supplement in the NEJM study was a special high-quality preparation--and that consumers should use caution when buying fish oil because not all fish oil is the same.
"You really need high-quality, standardized material that's been processed and stored correctly before comparing results from one study to another study," Phipps said. "Our study used the pure, biologically active products in fish oil, known as 17-HDHA, and we've provided a clear line of evidence for why intake of high-quality fish oil is good."
Omega 3 polyunsaturated fatty acids have been shown to have many health benefits. Once ingested, they convert to special pro-resolving mediators that halt inflammation without also suppressing the immune system. They can be found in foods such as flax seed oil, salmon, tuna, anchovies, and walnuts.
Wednesday, February 8, 2017
There are no more excuses for being out of shape. Researchers at McMaster University have found that short, intense bursts of stair climbing, which can be done virtually anywhere, have major benefits for heart health.
The findings negate the two most common excuses of couch potatoes: no time and no access to the gym.
"Stair climbing is a form of exercise anyone can do in their own home, after work or during the lunch hour," says Martin Gibala, a professor of kinesiology at McMaster and lead author on the study. "This research takes interval training out of the lab and makes it accessible to everyone."
Previous studies have proven the benefits of vigorous stair climbing over sustained periods of time--up to 70 minutes a week--but scientists set out to determine if sprint interval training (SIT), which involves brief bursts of vigorous exercise separated by short periods of recovery, was an effective and time-efficient alternative for improving cardiorespiratory fitness.
Investigators recruited 31 sedentary but otherwise healthy women and tested the effect of two different protocols, each of which required a 10-minute time commitment, including warm-up, cool down and recovery periods.
The exercise sessions were conducted three times a week over the course of six weeks.
The first protocol involved three, 20-second bouts of continuous climbing in an 'all-out' manner. The results were then compared and contrasted to participants who ran through the same protocol using an exercise bike which has already been shown to improve fitness.
For the second experiment, participants vigorously climbed up and down one flight of stairs for periods of 60 seconds, an experiment which could be easily adopted for the home.
Both protocols, each involving a total time commitment of 30 minutes a week, increased cardiorespiratory fitness, an important healthy marker that is linked to longevity.
"Interval training offers a convenient way to fit exercise into your life, rather than having to structure your life around exercise," says Gibala, who has studied high-intensity interval training for more than a decade and recently wrote a book on its efficacy entitled, "The One Minute Workout."
The findings are published in the journal Medicine & Science in Sports & Exercise.