Friday, June 28, 2013
A high intake of fatty acids found in fish is associated with a 14% reduction in the risk of breast cancer in later life, finds a study published on bmj.com.
The results show that each 0.1 g per day or 0.1% energy per day increment of intake of n-3 polyunsaturated fatty acid (n-3 PUFA) derived from fish was associated with a 5% reduction in risk. To achieve this risk reduction, intake of oily fish such as salmon, tuna or sardines should be 1-2 portions per person per week.
Breast cancer is one of the most common cancers, accounting for 23% of total cancer cases and 14% of cancer deaths in 2008. Studies suggest that a healthy diet and lifestyle is crucial for the prevention of breast cancer, and dietary fat is one of the most intensively studied dietary factors closely related with risk.
The n-3 PUFAs include ALA, EPA, DPA and DHA. They are involved in chemical messaging in the brain, helping to regulate blood vessel activity and areas of the immune system. The main dietary sources of EPA, DPA and DHA come from oily fish, while ALA is found mainly in nuts, seeds, and leafy green vegetables.
Although n-3 PUFAs are the most promising types of fat to reduce cancer risk, results from human studies are inconsistent.
So a team of researchers based in China set out to investigate the association between fish and n-3 PUFA intake and the risk of breast cancer. Levels were measured from both dietary sources and blood tests.
They reviewed and analysed the results of 26 studies from the United States, Europe and Asia involving over 800,000 participants and over 20,000 cases of breast cancer.
Marine n-3 PUFA was associated with a 14% reduction of breast cancer between the highest and lowest category of marine n-3 PUFA intake. The risk was lowest in Asian populations, probably because fish intake is much higher in Asia than in western countries, say the authors.
Further analysis indicated a dose response: each 0.1 g per day or 0.1% energy per day increment of intake was associated with a 5% reduction in risk. However, no significant protective association was found for ALA - the plant based n-3 PUFA.
The authors say their analysis, together with previous publications, “supports a protective role of marine n-3 PUFA on the incidence of breast cancer.”
They conclude: “Our present study provides solid and robust evidence that marine n-3 PUFA are inversely associated with risk of breast cancer.”
Thursday, June 27, 2013
Higher levels of omega-3 fatty acids in the blood may reduce the risk for hip fractures in postmenopausal women, recent research suggests.
Scientists analyzed red blood cell samples from women with and without a history of having a broken hip. The study showed that higher levels of omega-3 fatty acids from both plant and fish sources in those blood cells were associated with a lower likelihood of having fractured a hip.
In addition to omega-3s, the researchers looked at omega-6 fatty acids, which are generally plentiful in a Western diet. The study also showed that as the ratio of omega-6 fatty acids to omega-3s increased, so did the risk for hip fracture.
Though the study did not define the mechanisms for these relationships, the researchers hypothesized that inflammation may contribute to bone resorption, the breaking down of bone caused by the release of cells called osteoclasts.
“Inflammation is associated with an increased risk of bone loss and fractures, and omega-3 fatty acids are believed to reduce inflammation. So we asked if we would see fractures decrease in response to omega-3 intake,” said Rebecca Jackson, the study’s senior author and a professor of endocrinology, diabetes and metabolism at The Ohio State University.
“One thing that was critically important was that we didn’t use self-report of food intake, because there can be errors with that. We looked directly at the exposure of the bone cell to the fatty acids, which is at the red blood cell level,” said Jackson, also associate dean for clinical research in Ohio State’s College of Medicine. “Red blood cell levels also give an indication of long-term exposure to these fatty acids, which we took into account in looking for a preventive effect.”
Broken hips are the most common osteoporosis-related fractures, with an estimated 350,000 occurring annually in the United States. About 20 percent of people die in the year following a hip fracture.
The research is published in a recent issue of the Journal of Bone and Mineral Research.
The observational study did not measure cause and effect, so the researchers say the findings are not definitive enough to suggest that taking omega-3 supplements would prevent hip fractures in postmenopausal women.
“We don’t yet know whether omega-3 supplementation would affect results for bone health or other outcomes,” said Tonya Orchard, assistant professor of human nutrition at Ohio State and first author of the study. “Though it’s premature to make a nutrition recommendation based on this work, I do think this study adds a little more strength to current recommendations to include more omega-3s in the diet in the form of fish, and suggests that plant sources of omega-3 may be just as important for preventing hip fractures in women.”
Omega-3 and omega-6 fatty acids are both polyunsaturated fatty acids and essential fatty acids, meaning they contribute to biological processes but must be consumed because the body does not produce them on its own. Previous research has suggested that while both types of fatty acids are linked to health benefits, omega-3 fatty acids have anti-inflammatory properties and omega-6 fatty acids seem to have both anti- and pro-inflammatory effects.
The researchers used blood samples and hip fracture records from the Women’s Health Initiative (WHI), a large national prospective study of postmenopausal women that enrolled participants between 1993 and 1998 and followed them for 15 years. For this new work, the sample consisted of red blood cell samples and records from 324 pairs of WHI participants, half of whom had broken their hips before Aug. 15, 2008, and the other half composed of age-matched controls who had never broken a hip.
The analysis showed that higher levels of total omega-3 fatty acids and two other specific kinds of omega-3s alone were associated with a lower risk of hip breaks in the study sample.
On the other hand, women who had the highest ratio of omega-6 to omega-3 fatty acids had nearly twice the risk of hip fractures compared to women with the lowest ratios. The current typical American diet contains between 15 and 17 times more omega-6 than omega-3, a ratio that previous research has suggested should be lowered to 4-to-1, or even 2-to-1, by increasing omega-3s, to improve overall health. The primary omega-6 fatty acid in the diet is linoleic acid, which composes about 99 percent of Americans’ omega-6 intake and is found in corn, soybean, safflower and sunflower oils.
The specific omega-3 sources associated with lower risk for broken hips were ALA (alpha-linolenic acid), which comes from plant sources such as flaxseed oil and some nuts, and EPA (eicosapentaenoic acid), which is found in fatty types of fish. The other marine-sourced omega-3, DHA (docosahexaenoic acid), on its own did not have a significant link to lower hip-fracture risk, “but all three omega-3s were in the protective direction,” Orchard said.
Jackson, who was a vice chair of the WHI for more than a decade, said continuing analyses of data from the WHI will dig down to the genetic influences on metabolism and absorption of nutrients, and whether such genetic differences could affect health risk factors in postmenopausal women.
Thursday, June 20, 2013
A new study by Queen’s University researchers has determined that adults who accumulated 150 minutes of exercise on a few days of the week were not any less healthy than adults who exercised more frequently throughout the week.
Ian Janssen and his graduate student Janine Clarke studied 2,324 adults from across Canada to determine whether the frequency of physical activity throughout the week is associated with risk factors for diabetes, heart disease and stroke.
“The findings indicate that it does not matter how adults choose to accumulate their 150 weekly minutes of physical activity,” says Dr. Janssen. “For instance, someone who did not perform any physical activity on Monday to Friday but was active for 150 minutes over the weekend would obtain the same health benefits from their activity as someone who accumulated 150 minutes of activity over the week by doing 20-25 minutes of activity on a daily basis.”
Physical activity was measured continuously throughout the week by having research participants wear accelerometers on their waists. Accelerometers are tiny electrical devices (about the size of a small package of matches) that record how much a person moves every minute.
Dr. Janssen divided the adults who met the physical activity guidelines (more than 150 minutes per week of aerobic activity) into those who were frequently active (active five to seven days of the week) and infrequently active (active one to four days of the week).
“The important message is that adults should aim to accumulate at least 150 minutes of weekly physical activity in whatever pattern that works for their schedule.”
The paper was published today in Applied Physiology, Nutrition and Metabolism
Tuesday, June 18, 2013
Eating more red meat over time is associated with an increased risk of type-2 diabetes mellitus (T2DM) in a follow-up of three studies of about 149,000 U.S. men and women, according to a report published Online First by JAMA Internal Medicine, a JAMA Network publication.
Red meat consumption has been consistently related to an increased risk of T2DM, but previous studies measured red meat consumption at a baseline with limited follow-up information. However, a person's eating behavior changes over time and measurement of consumption at a single point in time does not capture the variability of intake during follow-up, the authors note in the study background.
An Pan, Ph.D., of the National University of Singapore, and colleagues analyzed data from three Harvard group studies and followed up 26,357 men in the Health Professionals Follow-up Study; 48,709 women in the Nurses' Health Study; and 74,077 women in the Nurses' Health Study II. Diets were assessed using food frequency questionnaires.
During more than 1.9 million person-years of follow-up, researchers documented 7,540 incident cases of T2DM.
"Increasing red meat intake during a four-year interval was associated with an elevated risk of T2DM during the subsequent four years in each cohort," according to the study.
The results indicate that compared with a group with no change in red meat intake, increasing red meat intake of more than 0.50 servings per day was associated with a 48 percent elevated risk in the subsequent four-year period. Reducing red meat consumption by more than 0.50 servings per day from baseline to the first four years of follow-up was associated with a 14 percent lower risk during the subsequent entire follow-up.
The authors note the study is observational so causality cannot be inferred.
"Our results confirm the robustness of the association between red meat and T2DM and add further evidence that limiting red meat consumption over time confers benefits for T2DM prevention," the authors conclude.
(JAMA Intern Med. Published online June 17, 2013. doi:10.1001/jamainternmed.2013.6633. Available pre-embargo to the media at http://media.jamanetwork.com.)
Editor's Note: This work was supported by grants from the National Institutes of Health. An author also made a funding disclosure. Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc.
Commentary: Oxygen-Carrying Proteins in Meat and Risk of Diabetes Mellitus
In an invited commentary, William J. Evans, Ph.D., of GlaxoSmithKline and Duke University, Durham, N.C., writes: "The article by Pan et al confirms previous observations that the consumption of so-called red meat is associated with an increased risk of type 2 diabetes mellitus (T2DM)."
"Perhaps a better description of the characteristics of the meat consumed with the greatest effect on risk is the saturated fatty acid (SFA) content rather than the amount of oxygen-carrying proteins," Evans continues.
"A recommendation to consume less red meat may help to reduce the epidemic of T2DM. However, the overwhelming preponderance of molecular, cellular, clinical and epidemiological evidence suggests that public health messages should be directed toward the consumption of high-quality protein that is low in total and saturated fat. … These public health recommendations should include cuts of red meat that are also low in fat, along with fish, poultry and low-fat dairy products. It is not the type of protein (or meat) that is the problem: it is the type of fat," Evans concludes.
Aspirin is known to lower risk for some cancers, and a new study led by a UC San Francisco scientist points to a possible explanation, with the discovery that aspirin slows the accumulation of DNA mutations in abnormal cells in at least one pre-cancerous condition.
"Aspirin and other non-steroidal anti-inflammatory drugs, which are commonly available and cost-effective medications, may exert cancer-preventing effects by lowering mutation rates," said Carlo Maley, PhD, a member of the UCSF Helen Diller Family Comprehensive Cancer Center, and an expert on how cancers evolve in the body over time.
In the study, published June 13 in the online journal PLOS Genetics, Maley, working with gastroenterologist and geneticist Brian Reid, MD, PhD, of the Fred Hutchinson Cancer Research Center, analyzed biopsy samples from 13 patients with a pre-cancerous condition called Barrett's esophagus who were tracked for six to 19 years. In an "observational crossover" study design, some patients started out taking daily aspirin for several years, and then stopped, while others started taking aspirin for the first time during observation. The goal was to track the rate of mutations in tissues sampled at different times.
The researchers found that biopsies taken while patients were on an aspirin had on average accumulated new mutations about 10 times more slowly than biopsies obtained during years when patients were not taking aspirin.
"This is the first study to measure genome-wide mutation rates of a pre-malignant tissue within patients for more than a decade, and the first to evaluate how aspirin affects those rates," Maley said.
Gender and ethnic distribution of study patients reflected the known demographics of esophageal cancer, which predominantly affects, white, middle-aged and elderly men, he said. Barrett's esophagus only occasionally progresses to esophageal cancer.
Cancers are known to accumulate mutations over time much more rapidly than normal tissue, and different mutations arise in different groups of cells within the same tumor. The acquisition of key mutations ultimately allows tumor cells to grow out of control, and diversity within a tumor may foster drug resistance, a phenomenon that is a major focus of Maley's research.
Maley plans to test a hypothesis that may explain the results — that aspirin's lowering of mutation rates is due to the drug's effect of reducing inflammation. Inflammation, a response of the immune system, in recent years has been recognized as a hallmark of cancer. Maley said that less inflammation may result in less production within pre-cancerous tissue of oxidants known to damage DNA, and may dampen growth-stimulating signaling.
For the duration of the study, the rate of accumulation of mutations measured in the biopsied tissue between time points was slow, even when patients were not taking aspirin, with the exception of one patient. While mutations accumulated at a steady rate, the vast majority of mutations arose before the abnormal tissue was first detected in the clinic, the researchers concluded.
These findings are consistent with the fact that although Barrett's esophagus is a significant risk factor for esophageal cancer, the vast majority of cases do not progress to cancer, Maley said.
In the one patient who later went on to develop cancer, a population of cellular "clones" with a great number of mutations emerged shortly before he started taking aspirin.
More studies are needed to further explore the link between non-steroidal anti-inflammatory drugs, mutation rates and the development of invasive cancer, Maley said. He plans to continue studying Barrett's esophagus and esophageal cancer, and to expand his research to investigate lung cancer.
Rather than aiming to kill the most tumor cells, it may be better to try to halt or slow growth and mutation. Current drug treatments for cancer may in many cases hasten the emergence of cancer that is more difficult to eradicate, according to Maley. The capability to mutate frequently allows tumors to become resistant to drug treatment, he said. A better-adapted mutant can begin to spin off a population of genetic clones that survives and grows, while poorly adapted tumor cells die off.
Taking calcium and vitamin D before exercise may influence how bones adapt to exercise, according to a new study. The results will be presented on Tuesday at The Endocrine Society's 95th Annual Meeting in San Francisco.
"The timing of calcium supplementation, and not just the amount of supplementation, may be an important factor in how the skeleton adapts to exercise training," said study lead author Vanessa D. Sherk, PhD, postdoctoral research fellow at the University of Colorado Anschutz Medical Campus. "Further research, however, is needed to determine whether the timing of calcium supplementation affects the skeletal adaptations to exercise training."
Previous research has shown that a year of intense training is associated with substantial decreases in bone mineral density among competitive road cyclists. Experts believe that this kind of exercise-induced bone loss could be related to the loss of calcium during exercise. As blood calcium levels drop, the parathyroid gland produces excess parathyroid hormone, which can mobilize calcium from the skeleton.
In this study, investigators found that an exercise-induced decrease in blood calcium occurred whether calcium supplements were taken before or after exercising. Pre-exercise supplementation, however, resulted in less of a decrease. Although not statistically significant, parathyroid hormone levels increased slightly less among cyclists who took calcium before exercising.
"These findings are relevant to individuals who engage in vigorous exercise and may lose a substantial amount of calcium through sweating," Sherk said. "Taking calcium before exercise may help keep blood levels more stable during exercise, compared to taking the supplement afterwards, but we do not yet know the long-term effects of this on bone density."
The timing of calcium supplementation did not cause a difference in blood levels of a compound that is a biological indicator of bone loss. Both the before- and after-exercise groups exhibited 50-percent increases in the level of this compound, called CTX, for collagen type-1 C-telopeptide.
Study participants included 52 men aged 18 to 45 years. Investigators randomly assigned participants to take 1,000 milligrams of calcium and 1,000 international units of vitamin D either 30 minutes before or one hour after exercise. The exercise comprised a simulated 35-kilometer time trial, and participants wore skin patches to absorb sweat.
Investigators measured blood levels of calcium and parathyroid hormone before and immediately after exercise. They also measured CTX before and 30 minutes after exercise. They used pre- and post-body weight, adjusted for fluid intake, combined with the calcium measured in the sweat from the skin patches, to estimate the amount of calcium lost through the skin during exercise.
Monday, June 17, 2013
The world's largest study to examine the link between vitamin D levels and hypertension has found that low levels of Vitamin D can be a major cause of hypertension.
Researchers presented their findings at the annual conference of the European Society of Human Genetics (ESHG).
Data were gathered from 35 studies, which included more than 155,000 participants from different parts of Europe and North America.
Dr. Vimal Karani S, from the Institute of Child Health, University College London, London, UK, led the study.
Participants with high levels of 25-hydroxyvitamin D (25(OH)D) had reduced blood pressure and were at a lower risk of developing hypertension.
Dr. Vimal Karani S, said:
"We knew from earlier observational studies that low 25(OH)D concentrations were likely to be associated with increases in blood pressure and hypertension, but correlation is not causality.
Additionally, randomized controlled trials of vitamin D supplementation in humans have produced inconsistent effects on cardiovascular outcomes. The whole picture was somewhat confused, and we decided to try to figure it out once and for all."
To measure the individuals' vitamin D status and test for an association with blood pressure, the researchers used genetic variations called single nucleotide polymorphisms, or SNPs as proxy markers.
For every 10% increase in 25(OH)D concentrations the researchers noted the risk of developing hypertension decreased by 8.1%.
Dr. Karani S., said that the approach they followed, called Mendelian randomization, allowed them to make accurate conclusions, "by using this approach we can determine the cause and effect and be pretty sure that we've come to the right conclusion on the subject."
The researchers said that Vitamin D deficiency is a very common problem in the Western world, particularly because obesity can cause Vitamin D deficiency and obesity levels are highest in Western countries, according to a study published in a recent issue of PLoS Medicine
People with high levels of vitamin D in their blood enjoy several benefits, apart from improved bone health. Researchers from Boston University School of Medicine reported in PLOS ONE that people with high levels of vitamin D have significantly better immunity and a reduced risk of several diseases.
Vitamin D insufficiency (between 21-29 ng/mL) and vitamin D deficiency (<20 ng/mL) lead to a heightened risk of:
Dr. Karani said that the study provides further data to support the importance of vitamin D. It suggests that vitamin D supplements or food fortification can significantly reduce the risk of cardiovascular disease.
"We now intend to continue this work by examining the causal relationship between vitamin D status and other cardiovascular disease-related outcomes such as lipid-related phenotypes, for example,cholesterol, inflammatory markers such as C-reactive protein, and type 2 diabetes and markers of glucose metabolism.
We believe that we still have a lot to find out about the effect of Vitamin D deficiency on health, and we now know that we have the tools to do so."
Monday, June 10, 2013
UC San Francisco-led study finds consuming olive oil and nuts may improve survival
Men with prostate cancer may significantly improve their survival chances with a simple change in their diet, a new study led by UC San Francisco has found.
By substituting healthy vegetable fats – such as olive and canola oils, nuts, seeds and avocados – for animal fats and carbohydrates, men with the disease had a markedly lower risk of developing lethal prostate cancer and dying from other causes, according to the study.
The research, involving nearly 4,600 men with non-metastatic prostate cancer, could help with the development of dietary guidelines for men with the disease. While prostate cancer affects millions of men around the world, little is known about the relationship between patients' diets following their diagnosis and progression of the disease.
The study will be published online on Monday, June 10, 2013, in JAMA Internal Medicine.
"Consumption of healthy oils and nuts increases plasma antioxidants and reduces insulin and inflammation, which may deter prostate cancer progression," said lead author Erin L. Richman, ScD, a post-doctoral scholar in the UCSF Department of Epidemiology and Biostatistics.
"The beneficial effects of unsaturated fats and harmful effects of saturated and trans fats on cardiovascular health are well known," Richman said. "Now our research has shown additional potential benefits of consuming unsaturated fats among men with prostate cancer."
Nearly 2.5 million men in the United States currently live with prostate cancer and another quarter-million men are expected to be diagnosed this year. One in six men in the U.S. will be diagnosed with the disease during their lifetime.
In recent years, evidence has indicated that diet might be an important way for men with prostate cancer to take an active role in determining their disease outcome and overall health. Research on advanced prostate cancer has suggested that fat intake may be relevant to disease progression, but this is the first study to examine fat consumption post-diagnosis in relation to risk of lethal prostate cancer and overall survival.
The new paper analyzed intake of saturated, monounsaturated, polyunsaturated and trans fats as well as fats from animal and vegetable sources.
The data were derived from the Health Professionals Follow-up Study, which began in 1986 and is sponsored by the Harvard School of Public Health and is funded by the National Cancer Institute.
The fat intake study involved 4,577 men who had been diagnosed with non-metastatic prostate cancer between 1986 and 2010. During the study timeframe, 1,064 men died, primarily from cardiovascular disease (31 percent), prostate cancer (21 percent) and other cancers (nearly 21 percent).
The authors uncovered a striking benefit: Men who replaced 10 percent of their total daily calories from carbohydrates with healthy vegetable fats had a 29 percent lower risk of developing lethal prostate cancer and a 26 percent lower risk of dying from all causes.
Adding a single serving of oil-based dressing a day (one tablespoon) was associated with a 29 percent lower risk of lethal prostate cancer and a 13 percent lower risk of death, the authors found. And adding one serving of nuts a day (one ounce) was associated with an 18 percent lower risk of lethal prostate cancer and an 11 percent lower risk of death.
The study adjusted for factors such as age, types of medical treatment, body mass index, smoking, exercise and other dietary factors, elevated blood pressure, cholesterol at the time of prostate cancer diagnosis and other health conditions. The researchers say further research is needed on the potential benefits of healthy fats among prostate cancer patients.
"Overall, our findings support counseling men with prostate cancer to follow a heart-healthy diet in which carbohydrate calories are replaced with unsaturated oils and nuts to reduce the risk of all-cause mortality," said Erin Richman, the first author.
A typical American consumes approximately 3 or more tablespoons of vegetable oil each day. Vegetable oils, like those from soy, corn and canola, are a significant source of calories and are rich in linoleic acid (LA), which is an essential nutrient. Since the 1970s, researchers have known that LA helps reduce blood cholesterol levels, and for decades, scientists have known that consuming LA can help lower the risk of heart disease. However, some experts have been claiming recently that Americans might be getting too much of a good thing. A new study from the University of Missouri contradicts that claim.
In the study, "Effect of Dietary Linoleic Acid on Markers of Inflammation in Healthy Persons: A Systematic Review of Randomized Controlled Trials," researchers at the University of Missouri and the University of Illinois found that no link exists between vegetable oil consumption and circulating indicators of inflammation that are often associated with diseases such as heart disease, cancer, asthma and arthritis. While earlier animal studies have shown that a diet rich in LA can promote inflammation, MU animal sciences researcher Kevin Fritsche says that humans respond to LA differently.
"In the field of nutrition and health, animals aren't people," said Fritsche, an MU professor of animal science and nutrition in the Division of Animal Sciences. "We're not saying that you should just go out and consume vegetable oil freely. However, our evidence does suggest that you can achieve a heart-healthy diet by using soybean, canola, corn and sunflower oils instead of animal-based fats when cooking."
Linoleic acid is an omega-6 fatty acid that is a major component of most vegetable oils. This fatty acid is an essential nutrient and comprising 50 percent or more of most vegetable oils.
Fritsche, along with Guy Johnson, an adjunct professor of food and human nutrition at the University of Illinois, conducted one of the most thorough studies on LA questioning whether this fatty acid promotes inflammation in humans. When the evidence from numerous clinical trials was gathered and examined, Fritsche said it was clear that LA consumption did not promote inflammation in healthy people.
"Some previous studies have shown that inflammation, which is an immune response in the body, can occur when certain fats are consumed," Fritsche said. "We've come to realize that this inflammation, which can occur anywhere in the body, can cause or promote chronic diseases. We know that animal fats can encourage inflammation, but in this study, we've been able to rule out vegetable oil as a cause."
Fritsche and Johnson reviewed 15 clinical trials that studied nearly 500 adults as they consumed various forms of fats, including vegetable oils. The researchers could find no evidence that a diet high in linoleic acid had any links to inflammation in the body. Due to this discovery, the researchers say that it is important to continue following the current recommendations from the Institute of Medicine and the American Heart Association to use vegetable oil when cooking and consume between two and four tablespoons of vegetable oil daily to reach the necessary amount of linoleic acid needed for a heart-healthy diet.
"Consumers are regularly bombarded with warnings about what foods they should avoid," Fritsche said. "While limiting the overall fat intake is also part of the current nutrition recommendations, we hope people will feel comfortable cooking with vegetable oils."
Wednesday, June 5, 2013
Fish oil supplements may protect the heart in stressful situations, according to a recent study. Jason Carter, a researcher at Michigan Technological University, conducted the study with 67 healthy volunteer test participants in their 20s. Over a 2-month period, they were either given nine grams of fish oil pills or nine grams of olive oil as a placebo.
The test subjects were screened for heart rate, blood pressure and other related metrics. At the end of the test period, both groups took a mental arithmetic test that involved adding and subtracting numbers in their head. Their stress response was measured at that time.
“Those in the fish oil group showed blunted heart rate reactivity while they were stressed compared to those who took olive oil," said Carter. "Similarly, the total [muscle sympathetic nerve activity] reactivity to mental stress was also blunted in the fish oil group.” There was not much difference between the two groups at rest, however.
Results of the study were published in the May edition of the American Journal of Physiology – Regulatory, Integrative, and Comparative Physiology, published by the American Physiological Society. It is available online at http://bit.ly/10j0CSS
While aspirin has been shown to be effective in preventing heart attacks in men, it also increases the risk of gastrointestinal bleeding and possibly stroke, even at low doses. As such, national guidelines suggest that aspirin be used for prevention only in men at higher risk for cardiovascular events, so that the benefits of aspirin are greater than its adverse effects.
Recent data suggest that aspirin may also be effective for reducing cancer deaths. Would the possible combined health benefits of reducing heart attacks and cancer outweigh the risks of gastrointestinal bleeding and stroke for middle-aged men?
A research team, including UNC scientists, reports that including the positive effect of aspirin on cancer mortality influences the threshold for prescribing aspirin for primary prevention in men. The benefit of aspirin for cancer mortality prevention would help offset the risks and thus lower the age and increase the number of men for whom aspirin is recommended.
Their results were published in the June issue of the Journal of General Internal Medicine.
Michael Pignone, MD, MPH, and study lead author, says, “We found that including a risk reduction for cancer deaths had a substantial impact on the overall benefits of aspirin, especially for early middle-aged men from 45 to 55 years of age. Based on this effect, several million men who were not previously good candidates for aspirin prevention would now become eligible.
The U.S. Preventive Services Task Force, of which Dr. Pignone is a recently appointed member, recommends aspirin for primary prevention in men “when the potential benefit of a reduction in myocardial infarctions outweighs the potential harm of an increase in gastrointestinal hemorrhage.” This recommendation was issued in 2009, before the potential benefits for cancer reduction were recognized.
People who eat farm-raised salmon can increase their intake of beneficial omega-3 fatty acids to levels that may help reduce their risk of heart disease, according to studies by U.S. Department of Agriculture (USDA) scientists.
The studies by Agricultural Research Service (ARS) nutritionist Susan Raatz and physiologist Matthew Picklo address concerns about whether farm-raised salmon have less available omega-3s than salmon caught in the wild. The scientists work at the ARS Grand Forks Human Nutrition Research Center in Grand Forks, N.D. ARS is USDA's principal intramural scientific research agency.
Two omega-3 fatty acids—EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid)—are abundant in oily fish such as salmon, tuna, mackerel, and herring. Consuming 250 milligrams daily of EPA and DHA—the amount in a 3-ounce farmed salmon fillet—has been associated with reduced heart disease risk.
The scientists evaluated a group of 19 healthy human volunteers who were provided three different portion sizes of farm-raised Atlantic salmon. Each volunteer was assigned to consume two weekly servings of one of the three portion sizes of salmon for a four-week period. After a "blood-clearing" break of four to six weeks, a different portion size was served, followed by another break. Then the third portion size was served, so that each volunteer had tested all three portion sizes.
The raw weights of the salmon portions fed to the volunteers were 90 grams (about 3.2 ounces), 180 grams (about 6.3 ounces), and 270 grams (about 9.5 ounces). The Dietary Guidelines for Americans recommend consuming 8 ounces of seafood weekly.
Blood was collected from each of the 19 subjects to mark fatty acid levels and other heart disease risk indicators at the beginning and end of each treatment. The results showed that EPA blood levels doubled after the volunteers consumed the 6.3-ounce portions and increased nearly threefold after they consumed the 9.5-ounce portions. Also, based on the blood indicators, DHA levels were elevated by about 50 percent, regardless of portion size.
This research was published in the Journal of the Academy of Nutrition and Dietetics.
Tuesday, June 4, 2013
Endometrial cancer patients who took statins and aspirin reduced their chance of death by a highly significant 84 percent, according to a new study by researchers at Montefiore Einstein Center for Cancer Care. Additionally, women who used only statins saw their risk of dying decline by 45 percent. The study was presented today at the annual meeting of the American Society of Clinical Oncology in Chicago.
Endometrial cancer is the most common cancer of the female reproductive organs and includes several types of malignancies that appear in the lining of the uterus. The American Cancer Society estimates nearly 50,000 new cases of endometrial cancer will be diagnosed in the United States this year, and more than 8,100 women will die from it. More than half of women diagnosed with endometrial cancer are in the 50-69 age group.
“These data are important as we explore the use of statins in patients with conditions beyond cardiovascular disease,” said lead author Nicole Nevadunsky, M.D., gynecologic oncologist, MECCC and Assistant Professor, Department of Obstetrics & Gynecology and Women's Health, Albert Einstein College of Medicine of Yeshiva University. “We were pleased by these results and are continuing our efforts to understand the unexpected positive effects of these medications in endometrial cancer.”
This retrospective study analyzed medical records of 554 patients diagnosed with endometrial cancer between January 2005 and December 2009. Among them, 165 patients were on statin therapy and 68 women were taking both statins and aspirin. All patients were treated at Montefiore Medical Center.
“It is not uncommon for women in their 50s and 60s to take statins and aspirin to treat cardiovascular conditions like high cholesterol or hypertension. Given the clear association we saw between statin and aspirin use and improved cancer survival, further evaluation is warranted to help us better understand how these medications may improve survival in endometrial and other cancers,” Dr. Nevadunsky said.
Monday, June 3, 2013
Study shows clear benefits of a healthy diet, exercise, maintaining normal weight and not smoking
A large, multi-center study led by Johns Hopkins researchers has found a significant link between lifestyle factors and heart health, adding even more evidence in support of regular exercise, eating a Mediterranean-style diet, keeping a normal weight and, most importantly, not smoking.
The researchers found that adopting those four lifestyle behaviors protected against coronary heart disease as well as the early buildup of calcium deposits in heart arteries, and reduced the chance of death from all causes by 80 percent over an eight-year period. Results of the study, "Low-Risk Lifestyle, Coronary Calcium, Cardiovascular Events, and Mortality: Results from the Multi-Ethnic Study of Atherosclerosis," are described in an online article posted June 3, 2013 by the American Journal of Epidemiology.
"To our knowledge, this is the first study to find a protective association between low-risk lifestyle factors and early signs of vascular disease, coronary heart disease and death, in a single longitudinal evaluation," says Haitham Ahmed, M.D., M.P.H., the lead author who is an internal medicine resident with the Ciccarone Center for the Prevention of Heart Disease at Johns Hopkins.
"We evaluated data on more than 6,200 men and women, age 44-84, from white, African-American, Hispanic and Chinese backgrounds. All were followed for an average of 7.6 years. Those who adopted all four healthy behaviors had an 80 percent lower death rate over that time period compared to participants with none of the healthy behaviors," says Ahmed.
Study participants all took part in the ongoing Multi-Ethnic Study of Atherosclerosis (MESA), a prospective examination of the risk factors, prevalence and prevention of cardiovascular disease. MESA participants were recruited from six academic medical centers and did not have a diagnosis of cardiovascular disease when they were enrolled.
All participants had coronary calcium screening using computed tomography (a CT scan) when they were first enrolled in the study to see if there were early signs of calcium deposits in their heart arteries that are known to contribute to heart attack risk. As the study progressed, the researchers also assessed whether the participants had a heart attack, sudden cardiac arrest, chest pain, angioplasty or died due to coronary heart disease or other causes.
The researchers developed a lifestyle score for each of the participants, ranging from 0 (least healthy) to 4 (healthiest), based on their diet, body mass index (BMI), amount of regular moderate-intensity physical activity and smoking status. Only 2 percent, or 129 participants, satisfied all four healthy lifestyle criteria.
"Of all the lifestyle factors, we found that smoking avoidance played the largest role in reducing the risk of coronary heart disease and mortality," says Roger Blumenthal, M.D., a cardiologist and professor of medicine at the Johns Hopkins University School of Medicine, director of the Ciccarone Center and senior author of the study. "In fact, smokers who adopted two or more of the healthy behaviors still had lower survival rates after 7.6 years than did nonsmokers who were sedentary and obese."
Blumenthal, who is also the president of the American Heart Association's Maryland affiliate, says the findings "bolster recent recommendations by the American Heart Association, which call for maintaining a diet rich in vegetables, fruits, nuts, whole grains and fish, keeping a BMI of less than 25, being physically active and not smoking."
The researchers emphasize that their study shows the importance of healthy lifestyle habits not just for reducing the risk of heart disease, but also for preventing mortality from all causes.
"While there are risk factors that people can't control, such as their family history and age," says Ahmed, "these lifestyle measures are things that people can change and consequently make a big difference in their health. That's why we think this is so important."
Using cholesterol-lowering statins may be associated with musculoskeletal conditions, arthropathies (joint diseases) and injuries, according to a report published Online First by JAMA Internal Medicine, a JAMA Network publication.
While statins effectively lower cardiovascular illnesses and death, the full spectrum of statin musculoskeletal adverse events (AEs) is unknown. Statin-associated musculoskeletal AEs include a wide variety of clinical presentations, including muscle weakness, muscle cramps and tendinous (tendon) diseases, the authors write in the study background.
Ishak Mansi, M.D., of the VA North Texas Health Care System, Dallas, and colleagues utilized data from a military health care system to determine whether statins were associated with musculoskeletal conditions based on statin use during the 2005 fiscal year. Patients were divided into two groups: statin users for at least 90 days and nonusers. A total of 46,249 patients met the study criteria and of those, researchers propensity score-matched (a statistical approach that mathematically matches the characteristics of patients in two or more groups) 6,967 statin users with 6,967 nonusers.
"Musculoskeletal conditions, arthropathies, injuries and pain are more common among statin users than among similar nonusers. The full spectrum of statins' musculoskeletal adverse events may not be fully explored, and further studies are warranted, especially in physically active individuals," the authors notes.
Statin users had a higher odds ratio (OR) for musculoskeletal disease diagnosis group 1 (all musculoskeletal diseases: OR, 1.19), for musculoskeletal disease diagnosis group 1b (dislocation/strain/sprain: OR, 1.13) and for musculoskeletal diagnosis group 2 (musculoskeletal pain: OR, 1.09), but not for musculoskeletal disease diagnosis group 1a (osteoarthritis/arthropathy: OR,1.07), according to study results for the propensity score-matched pairs.
'To our knowledge, this is the first study, using propensity score matching, to show that statin use is associated with an increased likelihood of diagnoses of musculoskeletal conditions, arthropathies and injuries. In our primary analysis, we did not find a statistically significant association between statin use and arthropathy; however, this association was statistically significant in all other analyses," the authors conclude. "These findings are concerning because starting statin therapy at a young age for primary prevention of cardiovascular diseases has been widely advocated."
Vegetarian diets are associated with reduced death rates in a study of more than 70,000 Seventh-day Adventists with more favorable results for men than women, according to a report published Online First by JAMA Internal Medicine, a JAMA Network publication.
The possible relationship between diet and mortality is an important area of study. Vegetarian diets have been associated with reductions in risk for several chronic diseases, including hypertension, metabolic syndrome, diabetes mellitus and ischemic heart disease (IHD), according to the study background.
Michael J. Orlich, M.D., of Loma Linda University in California, and colleagues examined all-cause and cause-specific mortality in a group of 73,308 men and women Seventh-day Adventists. Researchers assessed dietary patients using a questionnaire that categorized study participants into five groups: nonvegetarian, semi-vegetarian, pesco-vegetarian (includes seafood), lacto-ovo-vegetarian (includes dairy and egg products) and vegan (excludes all animal products).
The study notes that vegetarian groups tended to be older, more highly educated and more likely to be married, to drink less alcohol, to smoke less, to exercise more and to be thinner.
"Some evidence suggests vegetarian dietary patterns may be associated with reduced mortality, but the relationship is not well established," the study notes.
There were 2,570 deaths among the study participants during a mean (average) follow-up time of almost six years. The overall mortality rate was six deaths per 1,000 person years. The adjusted hazard ratio (HR) for all-cause mortality in all vegetarians combined vs. nonvegetarians was 0.88, or 12 percent lower, according to the study results. The association also appears to be better for men with significant reduction in cardiovascular disease mortality and IHD death in vegetarians vs. nonvegetarians. In women, there were no significant reductions in these categories of mortality, the results indicate.
"These results demonstrate an overall association of vegetarian dietary patterns with lower mortality compared with the nonvegetarian dietary pattern. They also demonstrate some associations with lower mortality of the pesco-vegetarian, vegan and lacto-ovo-vegetarian diets specifically compared with the nonvegetarian diet," the authors conclude.