Once again, more new research reports have been issued on topics I have already discussed than one person could possible keep up with. And yet, somehow, I have.
There is more distressing news on the two items I have written about most recently, sodium and folic acid, as well as, of course, more Vitamin D news. And more on Alcohol, Apples, Aspirin, Caffeine, Diet, Exercise, Fish (Omega-3), Green (and Black) Tea.
Light to moderate drinking and socialization are jointly good for cardiovascular health
• While heavy drinking is associated with a greater risk of stroke, light-to-moderate drinking has been linked to a lesser risk of ischemic stroke and coronary heart disease.
•
• New findings show that social support may enhance the beneficial effects of light-to-moderate alcohol consumption on risk of cardiovascular disease.
•
While heavy drinking is associated with a greater risk of stroke, light-to-moderate drinking has been linked to a lesser risk of ischemic stroke and coronary heart disease. Other studies have shown that more social support is linked to less risk of mortality and cardiovascular disease. A Japanese examination of the effects of social support on the relationship between drinking and cardiovascular disease has found that the health benefits of light-to-moderate drinking are more pronounced in men with greater social support.
Results will be published in the June issue of Alcoholism: Clinical & Experimental Research and are currently available at Early View.
"In Japan, drinking is divided into two main patterns," said Hiroyasu Iso, a professor of public health at Osaka University and corresponding author for the study. "One pattern is drinking alone and/or with family at home during the evening. Another pattern – especially for middle-aged business men – is social drinking with co-workers, friends, and neighbors. Social drinking is common."
"Alcohol can play a key role," concurred Takeshi Tanigawa, a professor in the department of public health at Ehime University Graduate School of Medicine, "for socializing as well as some business discussions. In urban areas, alcohol consumption is often used as a business tool. In rural areas, people often have a drink with classmates and people in the same community. Alcohol consumption can be used to maintain human relationships between father and son, senior and junior, community to community. Collectively, these socializing customs may help to create a stress-free space for those persons surrounded by dozens of stresses, especially in the workplace."
"Prior to our research," said Iso, "no study had examined whether psychosocial factors modify the association between alcohol consumption and risks of stroke and coronary heart disease."
Iso and his colleagues examined 19,356 men 40 to 69 years of age who were enrolled in the Japan Public Health Center-based Prospective Study. Their alcohol consumption was classified into seven categories: never, past, occasional, 1-149, 150-299, 300-449, or ≥450 grams/week. Measures used were alcohol consumption, risk of cardiovascular disease, and social support.
"We found the reduced risks of total stroke, ischemic stroke, and total cardiovascular disease associated with light-to-moderate drinking were more pronounced in men with high social support, probably due to avoidance of unhealthy behaviors and enhancement of stress buffering," said Iso. "In our study, compared with light-to-moderate drinkers with high social support, those with low social support had more unhealthy lifestyles such as physical inactivity, no job and fewer opportunities for medical checkups. Also, a potential pathway by which poor social support may lead to cardiovascular disease is mental stress. Mental stress activates neuro-endocrine components, including the hypothalamic-pituitary-adrenal-axis and autonomic nervous system, which lead to an increased risk of cardiovascular disease."
"In short," said Tanigawa, "moderate to light alcohol consumption with high social support is good for your health. Drinking with a good friend appropriately makes you feel happy and healthy. So drink with good friends for health," he advised. Tanigawa also recommended karaoke bars as one way for business persons to cope with stress. "Singers use deep breathing, which is good for the parasympathetic nervous system. After singing, they usually receive applause. It is a good kind of social support, and helps in the face of adverse occasions or stressful events."
Iso agreed that moderate alcohol consumption and socialization is good for one's health. "But remember that this beneficial effect of social support is confined to light-to-moderate drinking," he said. "Heavy drinking is risky irrespective of social support level. We believe that this also holds for other ethnic populations."
Apples Inhibiting Breast Cancer
Six studies published in the past year by a prominent Cornell researcher add to growing evidence that an apple a day -- as well as daily helpings of other fruits and vegetables -- can help keep the breast-cancer doctor away.
In one of his very recent papers, published in the Journal of Agricultural and Food Chemistry (57:1), Rui Hai Liu, Cornell associate professor of food science and a member of Cornell's Institute for Comparative and Environmental Toxicology, reports that fresh apple extracts significantly inhibited the size of mammary tumors in rats -- and the more extracts they were given, the greater the inhibition.
"We not only observed that the treated animals had fewer tumors, but the tumors were smaller, less malignant and grew more slowly compared with the tumors in the untreated rats," said Liu, pointing out that the study confirmed the findings of his preliminary study in rats published in 2007.
In his latest study, for example, he found that a type of adenocarcinoma -- a highly malignant tumor and the main cause of death of breast-cancer patients, as well as of animals with mammary cancer -- was evident in 81 percent of tumors in the control animals. However, it developed in only 57 percent, 50 percent and 23 percent of the rats fed low, middle and high doses of apple extracts (the equivalent of one, three and six apples a day in humans), respectively, during the 24-week study.
"That reflects potent anti-proliferative [rapid decrease] activity," said Liu.
The studies highlight the important role of phytochemicals, known as phenolics or flavonoids, found in apples and other fruits and vegetables.
Of the top 25 fruits consumed in the United States, Liu reported in the same journal (56:18) that apples provide 33 percent of the phenolics that Americans consume annually.
In a study of apple peel published in the same journal (56:21), Liu reported on a variety of new phenolic compounds that he discovered that also have "potent antioxidant and anti-proliferative activities" on tumors. And in yet another study in the same journal (56:24), he reported on his discovery of the specific modulation effects that apple extracts have on cell cycle machinery. Recently, Liu's group also reported the finding that apple phytochemicals inhibit an important inflammation pathway (NFkB) in human breast cancer cells.
Breast cancer is the most frequently diagnosed invasive cancer and the second leading cause of cancer deaths in women in the United States, said Liu. "These studies add to the growing evidence that increased consumption of fruits and vegetables, including apples, would provide consumers with more phenolics, which are proving to have important health benefits. I would encourage consumers to eat more and a wide variety of fruits and vegetables daily."
Risks of Using Aspirin to Prevent Heart Attack Or Stroke Differ by Gender and Age
Patients and clinicians should consider risk factors-- including age, gender, diabetes, blood pressure, cholesterol levels, smoking and risk of gastrointestinal bleeding-- before deciding whether to use aspirin to prevent heart attacks or strokes, according to new recommendations from the U.S. Preventive Services Task Force. These recommendations do not apply to people who have already had a heart attack or stroke.
The recommendations are published in the March 17 issue of the Annals of Internal Medicine. The Task Force reviewed new evidence from the National Institutes of Health’s Women’s Health Study published since the last Task Force review of this topic in 2002, including a recent meta-analysis of the risks and benefits of aspirin and found aspirin may have different benefits and harms in men and women. The Task Force found good evidence that aspirin decreases first heart attacks in men and first strokes in women.
The more risk factors people have, the more likely they are to benefit from aspirin. The Task Force recommends that men between the ages of 45 and 79 should use aspirin to reduce their risk for heart attacks when the benefits outweigh the harms for potential gastrointestinal bleeding. Women between the ages of 55 and 79 should use aspirin to reduce their risk for ischemic stroke when the benefits outweigh the harms for potential gastrointestinal bleeding. Ischemic strokes occur as a result of an obstruction within a blood vessel supplying blood to the brain and are potentially prevented by aspirin use. The risk of gastrointestinal bleeding with and without aspirin use increases with age and is twice as high in men as in women. Other risk factors for gastrointestinal bleeding include upper gastrointestinal tract pain, gastrointestinal ulcers, and using non-steroidal anti-inflammatory drugs.
The Task Force recommended against using aspirin to prevent either strokes or heart disease in men under 45 or women under age 55 because heart attacks are less likely to occur in men younger than 45 and ischemic strokes are less likely to occur in women younger than 55, and because limited evidence exists in these age groups.
People age 80 and older could benefit more than younger people from aspirin because of their higher risk of cardiovascular disease, but the harms are also greater because the risk of gastrointestinal bleeding increases with age. The Task Force could not find clear evidence that the benefits of using aspirin outweigh the risks in people 80 years or older.
“The decision about whether the benefits of taking aspirin outweigh the harms is an individual one. Patients should work with their clinicians to look at their risk factors and decide if taking aspirin to lower their risk for heart attacks or strokes outweighs the potential risk of gastrointestinal bleeding,” said Task Force Chair Ned Calonge, M.D., who is also chief medical officer and state epidemiologist for the Colorado Department of Public Health and Information.
Cardiovascular disease is the leading cause of death in the United States. It is the underlying or contributing cause in approximately 58 percent of all deaths. In 2003, 1 in every 3 adults had some type of cardiovascular disease. In adults over the age of 40, the risk of developing cardiovascular disease is 2 in 3 for men and more than 1 in 2 for women.
The Task Force could not find evidence about what the optimum dose of aspirin is to prevent heart attacks or strokes. Evidence shows benefits at a range of doses, and the risk of gastrointestinal bleeding may increase with the dose. A dose as low as 75 mg seems as effective as higher doses. Taking aspirin increases a person’s chances of gastrointestinal bleeding, the sudden loss of blood or perforation of the digestive tract that can lead to hospitalization or death. Taking aspirin also increases the chance of a hemorrhagic stroke, or bleeding in the brain, which is different than the ischemic stroke that aspirin can prevent.
In 2002, the Task Force strongly recommended that clinicians discuss aspirin use with adults at increased risk for coronary heart disease and that discussions with patients should address both the potential benefits and potential harms of aspirin therapy. The new recommendation provides more specific guidance about benefits and harms to specific age groups and gender-specific benefits and provides clinicians with information on how to estimate an individual’s risks for heart disease or stroke.
The U.S. Preventive Services Task Force is an independent panel of experts in prevention and primary care. The Task Force conducts rigorous, impartial assessments of the scientific evidence for the effectiveness of a broad range of clinical preventive services, including screening, counseling and preventive medications. Its recommendations are considered the gold standard for clinical preventive services.
Summary of Recommendations
• The USPSTF recommends the use of aspirin for men age 45 to 79 years when the potential benefit due to a reduction in myocardial infarctions outweighs the potential harm due to an increase in gastrointestinal hemorrhage.
•
• The USPSTF recommends the use of aspirin for women age 55 to 79 years when the potential benefit of a reduction in ischemic strokes outweighs the potential harm of an increase in gastrointestinal hemorrhage.
•
• The USPSTF concludes that the current evidence is insufficient to assess the balance of benefits and harms of aspirin for cardiovascular disease prevention in men and women 80 years or older._
•
• The USPSTF recommends against the use of aspirin for stroke prevention in women younger than 55 years and for myocardial infarction prevention in men younger than 45 years. _
•
Supporting Documents
Aspirin for the Prevention of Cardiovascular Disease, March 2009_ Recommendations and Rationale (PDF File, 335 KB; PDF Help)_ Supporting Article (PDF File, 160 KB; PDF Help) _ Evidence Synthesis (PDF File, 145 KB; PDF Help) _ Clinical Summary (PDF File, 114 KB; PDF Help
Caffeine reduces pain during exercise
Stopping to smell the coffee – and enjoy a cup of it – before your morning workout might do more than just get your juices flowing. It might keep you going for reasons you haven't even considered.
As a former competitive cyclist, University of Illinois kinesiology and community health professor Robert Motl routinely met his teammates at a coffee shop to fuel up on caffeine prior to hitting the pavement on long-distance training rides.
"The notion was that caffeine was helping us train harder … to push ourselves a little harder," he said.
The cyclists didn't know why it helped, they just knew it was effective.
"I think intuitively a lot of people are taking caffeine before a workout and they don't realize the actual benefit they're experiencing. That is, they're experiencing less pain during the workout," Motl said.
He said it's becoming increasingly common for athletes – before competing – to consume a variety of substances that include caffeine, motivated by "the notion that it will help you metabolize fat more readily."
"That research isn't actually very compelling," Motl said. "What's going on in my mind is … people are doing it for that reason, but they actually take that substance that has caffeine and they can push themselves harder. It doesn't hurt as much."
The U. of I. professor has been investigating the relationship between caffeine and physical activity since taking a slight detour during his doctoral-student days, when his work initially was focused on exploring possible links between caffeine intake, spinal reflexes and physical activity.
Seven years later, with several studies considering the relationship between physical activity and caffeine behind him, Motl has a much better understanding of why that cuppa Joe he used to consume before distance training and competing enhanced his cycling ability.
Early in his research, he became aware that "caffeine works on the adenosine neuromodulatory system in the brain and spinal cord, and this system is heavily involved in nociception and pain processing." Since Motl knew caffeine blocks adenosine from working, he speculated that it could reduce pain.
A number of studies by the U. of I. professor support that conclusion, including investigations considering such variables as exercise intensity, dose of caffeine, anxiety sensitivity and gender.
Motl's latest published study on the effects of caffeine on pain during exercise appears in the April edition of the International Journal of Sport Nutrition and Exercise Metabolism.
"This study looks at the effects of caffeine on muscle pain during high-intensity exercise as a function of habitual caffeine use," he said. "No one has examined that before.
"What we saw is something we didn't expect: caffeine-naïve individuals and habitual users have the same amount of reduction in pain during exercise after caffeine (consumption)."
The study's 25 participants were fit, college-aged males divided into two distinct groups: subjects whose everyday caffeine consumption was extremely low to non-existent, and those with an average caffeine intake of about 400 milligrams a day, the equivalent of three to four cups of coffee.
After completing an initial exercise test in the lab on an ergometer, or stationary cycle, for determination of maximal oxygen consumption or aerobic power, subjects returned for two monitored high-intensity, 30-minute exercise sessions.
An hour prior to each session, cyclists – who had been instructed not to consume caffeine during the prior 24-hour period – were given a pill. On one occasion, it contained a dose of caffeine measuring 5 milligrams per kilogram of body weight (equivalent to two to three cups of coffee); the other time, they received a placebo.
During both exercise periods, subjects' perceptions of quadriceps muscle pain was recorded at regular intervals, along with data on oxygen consumption, heart rate and work rate.
"What's interesting," Motl said, "is that when we found that caffeine tolerance doesn't matter, we were perplexed at first. Then we looked at reviews of the literature relative to caffeine and tolerance effects across a variety of other stimuli. Sometimes you see them, sometimes you don't. That is, sometimes regular caffeine use is associated with a smaller response, whereas, other times, it's not."
No one's been able to figure out the reason for the inconsistency, Motl said.
"Clearly, if you regularly consume caffeine, you have to have more to have that bigger, mental-energy effect. But the tolerance effect is not ubiquitous across all stimuli. Even brain metabolism doesn't show this tolerance-type effect. That is, with individuals who are habitual users versus non-habitual users, if you give them caffeine and do brain imaging, the activation is identical. It's really interesting why some processes show tolerance and others don't."
Regarding the outcome of the current research, he said, "it may just be that pain during exercise doesn't show tolerance effects to caffeine."
Motl said one of the next logical steps for his research team would be to conduct studies with rodents in order to better understand the biological mechanism for caffeine in reducing pain.
"If we can get at the biological mechanism, we can begin to understand why there may or may not be this kind of tolerance."
Motl said another research direction might be to determine caffeine's effect on sport performance.
"We've shown that caffeine reduces pain reliably, consistently during cycling, across different intensities, across different people, different characteristics. But does that reduction in pain translate into an improvement in sport performance?"
Meanwhile, the current research could prove encouraging for a range of people, including the average person who wants to become more physically active to realize the health benefits.
"One of the things that may be a practical application, is if you go to the gym and you exercise and it hurts, you may be prone to stop doing that because pain is an aversive stimulus that tells you to withdraw. So if we could give people a little caffeine and reduce the amount of pain they're experiencing, maybe that would help them stick with that exercise.
"Maybe then they'll push a little harder as well … maybe get even better adaptations to the exercise."
Eating red and processed meat associated with increased risk of death
Individuals who eat more red meat and processed meat appear to have a modestly increased risk of death from all causes and also from cancer or heart disease over a 10-year period, according to a report in the March 23 issue of Archives of Internal Medicine, one of the JAMA/Archives journals. In contrast, a higher intake of white meat appeared to be associated with a slightly decreased risk for overall death and cancer death.
"Meat intake varies substantially around the world, but the impact of consuming higher levels of meat in relation to chronic disease mortality [death] is ambiguous," the authors write as background information in the article.
Rashmi Sinha, Ph.D., and colleagues at the National Cancer Institute, Rockville, Md., assessed the association between meat intake and risk of death among more than 500,000 individuals who were part of the National Institutes of Health-AARP Diet and Health Study. Participants, who were between 50 and 71 years old when the study began in 1995, provided demographic information and completed a food frequency questionnaire to estimate their intake of white, red and processed meats. They were then followed for 10 years through Social Security Administration Death Master File and National Death Index databases.
During the follow-up period, 47,976 men and 23,276 women died. The one-fifth of men and women who ate the most red meat (a median or midpoint of 62.5 grams per 1,000 calories per day) had a higher risk for overall death, death from heart disease and death from cancer than the one-fifth of men and women who ate the least red meat (a median of 9.8 grams per 1,000 calories per day), as did the one-fifth of men and women who ate the most vs. the least amount of processed meat (a median of 22.6 grams vs. 1.6 grams per 1,000 calories per day).
When comparing the one-fifth of participants who ate the most white meat to the one-fifth who ate the least white meat, those with high white meat intake had a slightly lower risk for total death, death from cancer and death from causes other than heart disease or cancer.
"For overall mortality, 11 percent of deaths in men and 16 percent of deaths in women could be prevented if people decreased their red meat consumption to the level of intake in the first quintile [one-fifth]. The impact on cardiovascular disease mortality was an 11 percent decrease in men and a 21 percent decrease in women if the red meat consumption was decreased to the amount consumed by individuals in the first quintile," the authors write. "For women eating processed meat at the first quintile level, the decrease in cardiovascular disease mortality was approximately 20 percent."
There are several mechanisms by which meat may be associated with death, the authors note. Cancer-causing compounds are formed during high-temperature cooking of meat. Meat also is a major source of saturated fat, which has been associated with breast and colorectal cancer. In addition, lower meat intake has been linked to a reduction in risk factors for heart disease, including lower blood pressure and cholesterol levels.
"These results complement the recommendations by the American Institute for Cancer Research and the World Cancer Research Fund to reduce red and processed meat intake to decrease cancer incidence," the authors conclude. "Future research should investigate the relation between subtypes of meat and specific causes of mortality."
(Arch Intern Med. 2009;169[6]:562-571. Available pre-embargo to the media at www.jamamedia.org.)
Editor's Note: This research was supported in part by the Intramural Research Program of the NIH, National Cancer Institute. Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc.
Editorial: Reducing Meat Consumption Has Benefits Beyond Better Health
"The publication by Sinha et al is timely," writes Barry M. Popkin, Ph.D., of the University of North Carolina, Chapel Hill, in an accompanying editorial. "There is a global tsunami brewing, namely, we are seeing the confluence of growing constraints on water, energy and food supplies combined with the rapid shift toward greater consumption of all animal source foods."
"Not only are components of the animal-source foods linked to cancer, as shown by Sinha et al, but many other researchers have linked saturated fat and these same foods to higher rates of cardiovascular disease," Dr. Popkin writes. "What do we do?"
Because there are health benefits to eating some red and white (although not processed) meats, the consensus is not for a complete shift to vegan or vegetarian diets, Dr. Popkin concludes. "Rather, the need is for a major reduction in total meat intake, an even larger reduction in processed meat and other highly processed and salted animal source food products and a reduction in total saturated fat."
Beverage Consumption a Bigger Factor in Weight
When it comes to weight loss, what you drink may be more important than what you eat, according to researchers at the Johns Hopkins Bloomberg School of Public Health. Researchers examined the relationship between beverage consumption among adults and weight change and found that weight loss was positively associated with a reduction in liquid calorie consumption and liquid calorie intake had a stronger impact on weight than solid calorie intake. The results are published in the April 1, 2009, issue of the American Journal of Clinical Nutrition.
“Both liquid and solid calories were associated with weight change, however, only a reduction in liquid calorie intake was shown to significantly affect weight loss during the 6-month follow up,” said Benjamin Caballero MD, PhD, senior author of the study and a professor with the Bloomberg School’s Department of International Health. “A reduction in liquid calorie intake was associated with a weight loss of 0.25 kg at 6 months and 0.24 kg at 18 months. Among sugar-sweetened beverages, a reduction of 1 serving was associated with a weight loss of 0.5 kg at 6 months and 0.7 kg at 18 months. Of the seven types of beverages examined, sugar-sweetened beverages were the only beverages significantly associated with weight change.”
Researchers conducted a prospective study of 810 adults aged 25-79 years old participating in the PREMIER trial, an 18-month randomized, controlled, behavioral intervention. Caballero along with colleagues from the Johns Hopkins School of Medicine; the National Heart, Lung, and Blood institute; Duke University; the Pennington Biomedical Research Center; the Kaiser Permanente Center for Health Research; the University of Alabama; and Pennsylvania State University measured participant’s weight and height using a calibrated scale and a wall-mounted stadiometer at both 6 and 18 months. Dietary intake was measured by conducting unannounced 24-hour dietary recall interviews by telephone. Researchers divided beverages into several categories based on calorie content and nutritional composition: sugar-sweetened beverages (regular soft drinks, fruit drinks, fruit punch, or high-calorie beverages sweetened with sugar), diet drinks (diet soda and other “diet” drinks sweetened with artificial sweeteners), milk (whole milk, 2 percent reduced-fat milk, 1 percent low-fat milk, and skim milk), 100 percent juice (100 percent fruit and vegetable juice), coffee and tea with sugar, coffee and tea without sugar and alcoholic beverages. They found that at 37 percent sugar-sweetened beverages were the leading source of liquid calories.
Consumption of liquid calories from beverages has increased in parallel with the obesity epidemic. Earlier studies by Bloomberg School researchers project that 75 percent of U.S. adults could be overweight or obese by 2015 and have linked the consumption of sugar-sweetened beverages to the obesity epidemic, which affects two-thirds of adults and increases the risk for adverse health conditions such as type 2 diabetes. Researchers recommend limited liquid calorie intake among adults and to reduce sugar-sweetened beverage consumption as a means to accomplish weight loss or avoid excess weight gain.
“Among beverages, sugar-sweetened beverages was the only beverage type significantly associated with weight change at both the 6- and 18-month follow up periods,” said Liwei Chen, MD, PhD, MHS, lead author of the study and a Bloomberg School graduate. “Changes in the consumption of diet drinks and alcoholic beverages were inversely associated with weight loss, but were not statistically significant. Our study supports policy recommendations and public health efforts to reduce intakes of liquid calories, particularly from sugar-sweetened beverages, in the general population.”
Physically Fit Women Less Likely to Die from Breast Cancer
Physically fit women are less likely to die from breast cancer, according to a study by researchers at the University of South Carolina Arnold School of Public Health.
The findings are published in the April issue of Medicine & Science in Sports & Exercise®, the official scientific journal of the American College of Sports Medicine.
The study of more than 14,000 women found that those with moderate or high aerobic fitness levels were much less likely to die from breast cancer, said Dr. Steve Blair, an Arnold School researcher and a past president of the American College of Sports Medicine.
“Women in the study’s lowest fitness category were nearly three times more likely to die from breast cancer than women in the most fit group,” he said.
“We believe this is the first study to evaluate the association of objectively measured fitness and risk of dying from breast cancer,” he said. “The results suggest a stronger protective effect than has been seen in most studies on self-reported physical activity and breast cancer, probably because the objective laboratory test of fitness is more accurate that self-reports of activity.”
Blair and his research team studied women from 20 to 83 years of age who had no previous history of breast cancer. The study participants received an initial medical examination that included a maximal exercise test on a treadmill, between 1973 and 2001, and were monitored for breast cancer mortality through 2003.
“The good news is that women who do at least 150 minutes of moderate-intensity activity, like walking, per week will escape the low fitness category,” he said. “Even better for some women, this activity can be accumulated in 10-minute bouts.”
This level of exercise meets the federal “Physical Activity Guidelines for Americans” recommendations, and can be easily achieved in 30 minutes of exercise five days/week.
To develop the highest fitness category in this study, Blair said, women should aim for the “high activity” level recommended by federal guidelines, which includes 300 minutes of moderate-intensity activity, such as walking, over the course of the week. This can be achieved through 150 minutes/week of more vigorous activity, such as jogging or taking an aerobics class.
“With more than 40,000 women dying each year from this disease, finding a strong association between fitness, which can be improved by the relatively inexpensive lifestyle intervention of regular physical activity, such as walking, is exciting,” Blair said.
In addition, the study found that women with high aerobic fitness had lower body mass index, better cholesterol levels, lower blood pressure, and fewer chronic conditions such as diabetes and cardiovascular disease.
“This study is more evidence that physical activity is critical to health across our lifespan,” Blair said.
The study’s findings correlate with the message of ACSM’s Exercise is Medicine™ program, which calls for physical activity to be a standard part of health care and preventive treatment.
Study Examines Power of Exercise to Prevent Breast Cancer
Women With Family History May Cut Their Risk Through Regular Workouts
A new federally funded University of Pennsylvania School of Medicine study aims to learn whether women at high risk of breast cancer can use exercise to meaningfully reduce their risk of getting the disease. Building on evidence that reducing estrogen in the body reduces cancer risk, and that elite female athletes experience a drop in estrogen levels that often cause them to stop ovulating and menstruating, the WISER Sister trial will investigate two different levels of regular treadmill exercise as a possible intervention for breast cancer risk reduction.
The stakes for women who carry BRCA genetic mutations are high – as many as 80 percent of them will develop breast or ovarian cancer during their lives – but options for risk reduction are drastic and few, and the choices may be unacceptable to some women. Previous Penn research shows that prophylactic mastectomy slashes carriers’ breast cancer risk by 90 percent, while prophylactic oophorectomy, or ovary removal, halves their breast cancer risk and reduces their chances of getting of ovarian cancer by about 85 to 90 percent. Though the surgeries are highly effective, they usher in quality of life concerns – particularly with regard to body image and sexuality – and the early menopause that results from ovary removal brings a woman’s childbearing years to an end. And the procedures aren’t recommended for women who have a family history of breast cancer but don’t carry the mutated genes.
“The decision to have these surgeries is so difficult that many women delay them, sometimes with terrible consequences. We would like to find out if exercise could buy high-risk women time they need to more safely think through their options,” says Kathryn Schmitz, PhD, MPH, an assistant professor in the Center for Clinical Epidemiology and Biostatistics who is leading the new study, in partnership with Susan Domchek, MD, director of the Abramson Cancer Center’s Cancer Risk Evaluation Program. “Exercise also has a number of health and stress reduction benefits that make it even more attractive for this population.”
Over the next three years, Schmitz's team will enroll 160 women ages 18 to 40, who must have an elevated risk of getting breast cancer based on her family history of the disease. BRCA carriers will be included among eligible women. However, participants will not be required to undergo genetic testing.
Previous research on estrogen exposure strongly suggests that reducing estrogens will result in reduced breast cancer risk in this population. The investigators plan to use their findings to offer effective exercise guidelines for high-risk women. Unlike surgery, exercise is a low-cost intervention with few side effects, so Schmitz is hopeful that the study results will offer risk-reduction tools to a larger swath of high-risk women, including minorities and other groups that may be underserved or lack access to genetic testing or proper early screening.
“We are interested in rigorously investigating all potential options to decrease cancer risk,” says Domchek, an associate professor of Medicine in the division of Hematology/Oncology. “Exercise is a wonderful intervention due to its numerous health benefits. However, it is important for us to quantify the amount of exercise needed and the potential benefits such exercise might provide.”
Although it is unknown how much the exercise interventions tested in the trial will reduce estrogen exposure, Schmitz says even evidence of marginal risk reduction -- that exercise may help delay breast cancer onset, decrease breast density to improve the accuracy of early screening tests, or result in smaller tumors -- could be of help to women planning risk reduction strategies during their 20s and 30s.
Trial participants will be placed into three randomized groups who will be followed for seven months. Each participant will receive a treadmill to use at home, which she will get to keep after the study is over. A “low dose” group will complete 150 minutes of exercise each week, the same amount recommended for general health and fitness, while a “high dose” group will do 300 minutes of exercise each week, similar to the workouts recommended for weight control. A third group, serving as the control, will continue doing their usual activities for the duration of the study and will receive the treadmill at the end of study completion.
Each woman will give daily urine samples at points during the trial, which will allow investigators to measure their levels of estrogen, progesterone and other sex hormones. The women’s body composition will also be measured, and they will receive breast MRIs at no cost to them before and after the study to examine changes in the density of their breast tissue.
“It is frightening to face high risk for breast cancer at a young age. Most of us think of cancer as something that happens later in life. Young women may not even want to approach the issue of getting genetic testing yet, but may want to do something. The WISER Sister study offers those women an option,” Schmitz says. “The benefits of the study will have a ripple effect to other good health habits, too, by helping women adopt a regular exercise regimen.”
Study Shows That Exercise Reduces Migraine Suffering
While physical exercise has been shown to trigger migraine headaches among sufferers, a new study describes an exercise program that is well tolerated by patients. The findings show that the program decreased the frequency of headaches and improved quality of life. The study is published in Headache: The Journal of Head and Face Pain.
The study used a sample of migraine sufferers who were examined before, during and after an aerobic exercise intervention. The program was based on indoor cycling (for continuous aerobic exercise) and was designed to improve maximal oxygen uptake without worsening the patients’ migraines.
After the treatment period, patients’ maximum oxygen uptake increased significantly. There was no worsening of migraine status at any time during the study period and, during the last month of treatment, there was a significant decrease in the number of migraine attacks, the number of days with migraine per month, headache intensity and amount of headache medication used.
Individuals with headache and migraine typically are less physically active than those without headache. Patients with migraine often avoid exercise, resulting in less aerobic endurance and flexibility. Therefore, well designed studies of exercise in patients with migraine are imperative.
“While the optimal amount of exercise for patients with migraine remains unknown, our evaluated program can now be tested further and compared to pharmacological and non-pharmacological treatments to see if exercise can prevent migraine,” says Dr. Emma Varkey, co-author of the study.
Omega-3 fatty acids reduce risk of advanced prostate cancer
Omega-3 fatty acids appear protective against advanced prostate cancer, and this effect may be modified by a genetic variant in the COX-2 gene, according to a report in Clinical Cancer Research, a journal of the American Association for Cancer Research.
"Previous research has shown protection against prostate cancer, but this is one of the first studies to show protection against advanced prostate cancer and interaction with COX-2," said John S. Witte, Ph.D., professor of epidemiology and biostatistics at the University of California San Francisco.
For the current study, researchers performed a case-control analysis of 466 men diagnosed with aggressive prostate cancer and 478 healthy men. Diet was assessed by a food frequency questionnaire and researchers genotyped nine COX-2 single nucleotide polymorphisms.
Researchers divided omega-3 fatty acid intake into four groups based on quartiles of intake. Men who consumed the highest amount of long chain omega-3 fatty acids had a 63 percent reduced risk of aggressive prostate cancer compared to men with the lowest amount of long chain omega-3 fatty acids.
The researchers then assessed the effect of omega-3 fatty acid among men with the variant rs4647310 in COX-2, a known inflammatory gene. Men with low long chain omega-3 fatty acid intake and this variant had a more than five-fold increased risk of advanced prostate cancer. But men with high intake of omega-3 fatty acids had a substantially reduced risk, even if they carried the COX-2 variant.
"The COX-2 increased risk of disease was essentially reversed by increasing omega-3 fatty acid intake by a half a gram per day," said Witte. "If you want to think of the overall inverse association in terms of fish, where omega-3 fatty acids are commonly derived, the strongest effect was seen from eating dark fish such as salmon one or more times per week."
Health Benefits, Consequences of Folic Acid Dependent on Circumstances
For the past several decades, evidence has shown that greater dietary intake of the B-vitamin, folate, offers protection against the development of certain common cancers and reduces neural tube defects in newborns, opening new avenues for public health interventions that have a great impact on health. However, folate’s central role as an essential factor in DNA synthesis also means that abundant availability of the vitamin can enhance the development of pre-cancerous and cancerous tumors. Further, the intake of folic acid that results from consuming foods that are voluntarily fortified (e.g.: ready-to-eat cereals) in combination with the additional intake received from mandatory fortification of flour means that supplementary intake of folic acid is unnecessary for many segments of the population, and may even present a risk. Nevertheless, the issue is a complicated one since women of child-bearing age seem to benefit from supplemental folic acid in regard to its protection against birth defects. In the April issue of the journal Nutrition Reviews, two new articles by Omar Dary, Ph.D., and Joel B. Mason, M.D., assess the conditions under which folic acid can be beneficial and harmful and contribute to guidelines for the healthful intake of folic acid as a complement to dietary folate.
The consequences of inadequate folate intake remain prevalent in many countries, even in industrial countries where specific interventions of folic acid have not been implemented. Moreover, there continues to be some concern—which, to date, lacks compelling scientific evidence—that the synthetic form of the vitamin, folic acid, might have adverse effects that do not exist with natural sources of folate.
Under most circumstances, adequate intake of folate appears to assume the role of a protective agent against cancer, most notably colorectal cancer. However, in select circumstances in which an individual who harbors a pre-cancerous or cancerous tumor consumes too much folic acid, the additional amounts of folate may instead facilitate the promotion of cancer. In countries in which the fortification of flour with folic acid is working well, additional supplementation in the form of vitamin pills can lead to excessive intakes of the vitamin, which can then have undesirable adverse effects.
Thus, folate appears to assume different guises depending on the circumstances. The level of intake of this micronutrient that is safe for one person may be potentially harmful to another.
“These effects of folate on the risk of developing cancer have created a global dilemma in the efforts to institute nationwide folic acid fortification programs around the world,” Mason notes.
Most individuals in the U.S. population are now folate-replete, so one consideration would be to reduce the doses of the vitamin that are present in most over-the-counter supplements. Many people receive sufficient amounts of folate through their diet.
Now that the supply of folic acid in the diet is much larger than it was prior to mandatory fortification, food policies may need to be adjusted to the current knowledge and the new circumstances.
“The design of cogent public health policies that effectively optimize health for many while presenting no or minimal risk to others, must often occur in the absence of complete information,” Mason concludes. “However, we are nevertheless obliged to deliberate with as much of an in-depth understanding as the existing science allows.”
Folic Acid Fortification May Be Linked to Increased Colon Cancer Risk
The rate of colorectal cancer in Chile may have increased since that country began fortifying wheat flour with folic acid, reports a study in the European Journal of Gastroenterology & Hepatology. The journal is published by Lippincott Williams & Wilkins, a part of Wolters Kluwer Health, a leading provider of information and business intelligence for students, professionals, and institutions in medicine, nursing, allied health, pharmacy and the pharmaceutical industry.
"Our data provide new evidence that a folate fortification program could be associated with an additional risk of colon cancer," according to the new report by Dr. Sandra Hirsch and colleagues of University of Chile, Santiago.
Possible Increase in Colon Cancer after Start of Folic Acid Fortification
The researchers analyzed changes in colon cancer rates since the Chilean government introduced a mandatory program of folic acid fortification of wheat flour in 2000. Several countries have implemented similar policies in recent years, with the goal of preventing spina bifida and other neural tube defects. In Chile, the rate of neural tube defects decreased by 40 percent in the first year after the start of folic acid fortification. __The researchers compared hospital discharge data on colon cancer rates in Chile in four-year periods before and after folic acid fortification: 1992-96 versus 2001-04. Although no causative relationship can be proven, the data suggested a significant "temporal relationship" between folic acid supplementation and colorectal cancer. Reported cases of colon cancer increased by 162 percent in people aged 45 to 64 and by 190 percent in people aged 65 to 79.
After adjustment for other factors, discharge diagnoses of colon cancer in these age groups were two to three times more frequent after the start of folic acid fortification. Most other diseases showed no consistent pattern of changes. There was a small increase in breast cancer, which may have been related to early detection and universal treatment programs for breast cancer.
Evidence Is Weaker than Similar Changes Reported in U.S. and Canada
Chile is the third country to report an apparent increase in colorectal cancer after introducing a national folic acid fortification program. A 2007 paper suggested increases in colorectal cancer after folic acid fortification was introduced in the United States and Canada in the mid-1990s. Chile uses a higher "dose" of folic acid than the two North American countries. Folic acid fortification has not yet been introduced in Europe.
There are other possible explanations for the rise in colon cancer in Chile, including increases in obesity and other risk factors.
Another important limitation of the study was the use of hospital discharge data to identify cases of colon cancer. "Discharge rates are influenced by health care politics, increasing access to healthcare for new strata of the population with increased cancer risk, and so forth," comments Dr. Reinhold Stockbrugger, one of the editors of The European Journal of Gastroenterology & Hepatology. "This study provides only a weak, indirect indication of a causal relationship between folate enrichment and colorectal cancer, though similar to that reported in the U.S. and Canada."
Health Benefits of Green Tea May Decrease After Long Storage
Green tea leaves produce antioxidant organic compounds called catechins that reportedly have beneficial health effects, such as fighting bacteria, viruses and cancer. But consumers need to be aware of possible adverse consequences of long-term storage of commercial tea brands, according to researchers Mendel Friedman and Carol Levin.
Because tea generally does not spoil, it can be stored for extended periods. However, catechins in commercial tea leaves may not remain stable during long-term storage in the solid state.
For the study, tea bags were stored in their original containers in the dark at room temperature for time periods ranging from one week to six months. “Degradation of catechins in commercial tea leaves during a storage time of six months in warehouses, stores or even the home could adversely impact tea’s potential health benefits,” say the researchers. Even in the absence of moisture, the quality of teas may degrade with time. The researchers added that different tea varieties are harvested in different ways and at different times of the year, which might affect their catechin content.
Drinking very hot tea can increase the risk of throat cancer
Tea drinking habits and oesophageal cancer in a high risk area in Northern Iran: Population based case-control study
People are advised to wait a few minutes before drinking a cup of freshly-boiled tea today as a new study, published on bmj.com, finds that drinking very hot tea (70°C or more) can increase the risk of cancer of the oesophagus, the muscular tube that carries food from the throat to the stomach.
The study was carried out in northern Iran, where large amounts of hot tea are drunk every day.
But an accompanying editorial says these findings are not cause for alarm and the general advice is to allow foods and beverages to cool a little before swallowing.
Cancers of the oesophagus kill more than 500,000 people worldwide each year and oesophageal squamous cell carcinoma (OSCC) is the commonest type. In Europe and America, it is mainly caused by tobacco and alcohol use and is more common in men than in women, but drinking hot beverages is also thought to be a risk factor.
Golestan Province in northern Iran has one of the highest rates of OSCC in the world, but rates of smoking and alcohol consumption are low and women are as likely to have a diagnosis as men. Tea drinking, however, is widespread, so researchers set out to investigate a possible link between tea drinking habits and risk of OSCC.
They studied tea drinking habits among 300 people diagnosed with OSCC and a matched group of 571 healthy controls from the same area. Nearly all participants drank black tea regularly, with an average volume consumed of over one litre a day.
Compared with drinking warm or lukewarm tea (65°C or less), drinking hot tea (65-69°C) was associated with twice the risk of oesophageal cancer, and drinking very hot tea (70°C or more) was associated with eight-fold increased risk.
Likewise, compared with drinking tea four or more minutes after being poured, drinking tea less than two minutes after pouring was associated with a five-fold higher risk.
There was no association between the amount of tea consumed and risk of cancer.
To minimise errors between reported and actual tea temperatures, the researchers then measured the actual temperature that tea was consumed by nearly 50,000 residents of the same area. This ranged from less than 60°C to more than 70°C and there was a moderate agreement between reported tea drinking temperature and actual temperature measurements.
Our results show a strong increase in the risk of oesophageal squamous cell carcinoma associated with drinking hot or very hot tea, say the authors.
Previous studies from the United Kingdom have reported an average temperature preference of 56-60°C among healthy populations.
They suggest that informing the population about the hazards of drinking hot tea may be helpful in reducing the incidence of oesophageal cancer in Golestan and in other high risk populations where similar habits are prevalent.
These results provide persuasive evidence that drinking tea at temperatures greater than 70°C markedly increases the risk of oesophageal squamous cell carcinoma, says David Whiteman from the Queensland Institute of Medical Research in Australia in an accompanying editorial.
This report also lends support to the notion that thermal injury may be a cause of epithelial cancers, though he points out that the way in which heat promotes tumour development is not clear and warrants further investigation.
However, he stresses that these findings are not cause for alarm, and they should not reduce public enthusiasm for the time honoured ritual of drinking tea. Instead he suggests waiting at least four minutes before drinking a cup of freshly boiled tea, or more generally allowing foods and beverages to cool from "scalding" to "tolerable" before swallowing.
CDC Sodium Study
In 2005, the U.S. Department of Health and Human Services and U.S. Department of Agriculture recommended that adults in the United States should consume no more than 2,300 mg/day of sodium (equal to approximately 1 tsp of salt), but those in specific groups (i.e., all persons with hypertension, all middle-aged and older adults, and all blacks) should consume no more than 1,500 mg/day of sodium (6). To estimate the proportion of the adult population for whom the lower sodium recommendation is applicable, CDC analyzed data from the National Health and Nutrition Examination Survey (NHANES) for the period 1999--2006. The results indicated that, in 2005--2006, the lower sodium recommendation was applicable to 69.2% of U.S. adults. Consumers and health-care providers should be aware of the lower sodium recommendation, and health-care providers should inform their patients of the evidence linking greater sodium intake to higher blood pressure.
Vitamin D supplements associated with reduced fracture risk in older adults
Oral vitamin D supplements at a dose of at least 400 international units per day are associated with a reduced risk of bone fractures in older adults, according to results of a meta-analysis published in the March 23 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.
"The anti-fracture benefits of vitamin D have been questioned by several recent trials, leading to uncertainty among patients and physicians regarding recommendations for vitamin D supplementation," the authors write as background information in the article. "Factors that may obscure a benefit of vitamin D are low adherence to treatment, low dose of vitamin D or the use of less potent ergocalciferol (vitamin D2)."
Heike A. Bischoff-Ferrari, Dr.P.H., of the University of Zurich, University Hospital, Zurich, Switzerland, and colleagues performed a meta-analysis on 12 previously published clinical trials of oral vitamin D supplements among adults age 65 or older. These double-blind randomized controlled trials involved 42,279 participants (average age 78) and looked at non-vertebral (non-spinal) fractures, including eight trials of 40,886 participants specifically studying hip fractures.
When the results of the trials were pooled, vitamin D supplements decreased the risk of non-vertebral fractures by 14 percent and of hip fractures by 9 percent. The authors then pooled the results of only the nine trials in which participants received doses of more than 400 international units per day. At this dosage, vitamin D supplements reduced non-vertebral fractures by 20 percent and hip fractures by 18 percent. Doses of 400 international units per day or lower did not reduce the risk of either fracture type. A greater reduction in risk was also seen among trial participants whose blood levels of 25-hydroxyvitamin D (a commonly used measure of blood vitamin D levels) achieved a greater increase.
Among individuals taking high doses of vitamin D, additional calcium did not appear to have any further protective effect against fractures. "Physiologically, the calcium-sparing effect of vitamin D may explain why we did not see an additional benefit of calcium supplementation at a higher dose of vitamin D," the authors write.
"The greater fracture reduction with a higher received dose or higher achieved 25-hydroxyvitamin D levels for both any non-vertebral fractures and hip fractures suggests that higher doses of vitamin D should be explored in future research to optimize anti-fracture efficacy," they conclude. "Also, it is possible that greater benefits may be achieved with earlier initiation of vitamin D supplementation and longer duration of use. Our results do not support use of low-dose vitamin D with or without calcium in the prevention of fractures among older individuals."
Vitamin D Fights Chronic Pain
Mayo Clinic research shows a correlation between inadequate vitamin D levels and the amount of narcotic medication taken by patients who have chronic pain. This correlation is an important finding as researchers discover new ways to treat chronic pain. According to the Centers for Disease Control and Prevention, chronic pain is the leading cause of disability in the United States. These patients often end up taking narcotic-type pain medication such as morphine, fentanyl or oxycodone.
This study found that patients who required narcotic pain medication, and who also had inadequate levels of vitamin D, were taking much higher doses of pain medication - nearly twice as much - as those who had adequate levels. Similarly, these patients self-reported worse physical functioning and worse overall health perception. In addition, a correlation was noted between increasing body mass index (a measure of obesity) and decreasing levels of vitamin D. Study results were published in a recent edition of Pain Medicine.
"This is an important finding as we continue to investigate the causes of chronic pain," says Michael Turner, M.D., a physical medicine and rehabilitation physician at Mayo Clinic and lead author of the study. "Vitamin D is known to promote both bone and muscle strength. Conversely, deficiency is an under-recognized source of diffuse pain and impaired neuromuscular functioning. By recognizing it, physicians can significantly improve their patients' pain, function and quality of life."
Researchers retrospectively studied 267 chronic pain patients admitted to the Mayo Comprehensive Pain Rehabilitation Center in Rochester from February to December 2006. Vitamin D levels at the time of admission were compared to other parameters such as the amount and duration of narcotic pain medication usage; self-reported levels of pain, emotional distress, physical functioning and health perception; and demographic information such as gender, age, diagnosis and body mass index.
Further research should document the effects of correcting deficient levels among these patients, researchers recommend.
This study has important implications for both chronic pain patients and physicians. "Though preliminary, these results suggest that patients who suffer from chronic, diffuse pain and are on narcotics should consider getting their vitamin D levels checked. Inadequate levels may play a role in creating or sustaining their pain," says Dr. Turner.
"Physicians who care for patients with chronic, diffuse pain that seems musculoskeletal - and involves many areas of tenderness to palpation - should strongly consider checking a vitamin D level," he says. "For example, many patients who have been labeled with fibromyalgia are, in fact, suffering from symptomatic vitamin D inadequacy. Vigilance is especially required when risk factors are present such as obesity, darker pigmented skin or limited exposure to sunlight."
Assessment and treatment are relatively simple and inexpensive. Levels can be assessed by a simple blood test (25-hydroxyvitamin D [25(OH)D]). Under the guidance of a physician, an appropriate repletion regimen can then be devised. Because it is a natural substance and not a drug, vitamin D is readily available and inexpensive.
In addition to the benefits of strong muscles and bones, emerging research demonstrates that vitamin D plays important roles in the immune system, helps fight inflammation and helps fights certain types of cancer.
Increasing number of Americans have insufficient levels of vitamin D
Average blood levels of vitamin D appear to have decreased in the United States between 1994 and 2004, according to a report in the March 23 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.
Clinicians previously believed the major health problems associated with vitamin D deficiency were rickets in children and reduced bone mineral content in adults, conditions reduced by fortifying foods with vitamin D, according to background information in the article. More recently, insufficient vitamin D levels have been associated with cancer, heart disease, infection and suboptimal health overall. Evidence suggests that levels of 30 nanograms per milliliter to 40 nanograms per milliliter may be needed for optimum health
"Vitamin D supplementation appears to mitigate the incidence and adverse outcomes of these diseases and may reduce all-cause mortality," the authors write. However, currently recommended levels of supplementation—200 international units per day from birth to age 50, 400 international units per day from age 51 to 70 and 600 international units per day for adults age 71 and older—focus primarily on improving bone health. In addition, decreases in outdoor physical activities and successful campaigns to reduce sun exposure may have contributed to vitamin D insufficiency, since sunlight exposure is a main determinant of vitamin D status in humans.
Adit A. Ginde, M.D., M.P.H., of the University of Colorado Denver School of Medicine, Aurora, and colleagues compared levels of serum 25-hydroxyvitamin D (25[OH]D, a measure of the amount of vitamin D in the blood) from the Third National Health and Nutrition Examination Survey (NHANES III), collected between 1988 and 1994, to those collected during NHANES 2001-2004. Complete data were available for 18,883 participants in the first survey and 13,369 participants in the second survey.
"Overall, the mean [average] serum 25(OH)D level in the U.S. population was 30 nanograms per milliliter during the 1988-1994 collection and decreased to 24 nanograms per milliliter during the 2001-2004 collection," the authors write. The prevalence of levels lower than 10 nanograms per milliliter increased from 2 percent to 6 percent between the two time periods, and fewer individuals had levels 30 nanograms per milliliter or higher (45 percent vs. 23 percent).
Racial and ethnic differences persisted throughout the surveys; among non-Hispanic blacks, the prevalence of 25(OH)D levels of less than 10 nanograms per milliliter increased from 9 percent to 29 percent and levels of more than 30 nanograms per milliliter or higher decreased from 12 percent to 3 percent.
"These findings have important implications for health disparities and public health," the authors write. "We found that the mean serum 25(OH)D level in the U.S. population dropped by 6 nanograms per milliliter from the 1988-1994 to the 2001-2004 data collections. This drop was associated with an overall increase in vitamin D insufficiency to nearly three of every four adolescent and adult Americans."
"Current recommendations for dosage of vitamin D supplements are inadequate to address this growing epidemic of vitamin D insufficiency," they conclude. "Increased intake of vitamin D (1,000 international units per day or more)—particularly during the winter months and at higher latitudes—and judicious sun exposure would improve vitamin D status and likely improve the overall health of the U.S. population. Large randomized controlled trials of these higher doses of vitamin D supplementation are needed to evaluate their effect on general health and mortality."
No comments:
Post a Comment