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September 2012
Contradicting other research on calorie restriction and longevity, a new National Institutes on Aging study reports that rhesus monkeys fed 30% fewer calories were healthier but didn’t live any longer than a control group. The monkeys — long-lived primates similar to humans — had been followed since 1987. Those on a restricted diet did have a lower incidence of cardiovascular disease, cancer and diabetes. But that didn’t translate into longer lifespans. Researchers in a similar study at the Wisconsin National Primate Center, who have reported longevity benefits linked to calorie restriction, pointed out potentially key differences between the studies: The control group in the NIA study was given vitamin and mineral supplements and fed a limited, though higher-calorie diet. In the Wisconsin experiment, monkeys in the control group were allowed free access to food, which those researchers argued more closely resembles actual human lifestyles. — Nature…
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August 2012
Maybe the theory that fish-oil pills can help protect your brain is, well, a little fishy. A new review of the evidence for a protective benefit from the omega-3 fatty acids in fish found no significant difference between fish-oil supplements and placebo. The analysis, for the prestigious Cochrane Review, looked at 3 high-quality clinical trials totaling 3,536 participants. Some previous observational studies have suggested that omega-3s might protect against cognitive decline, and that possibility makes sense, since fatty acids play an important role in brain health. But the review of clinical trials saw only tiny, statistically insignificant differences in performance on tests of memory, executive function and mental processing speed. One trial also used a test called the mini-mental status evaluation (MMSE), in which participants given omega-3s scored only 0.07 points apart from those on placebo. The trials used dosages of the omega-3s found in fish oil ranging from 400-700 mg and lasted from 6 to 40 months. — Cochrane Review…
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August 2012
Foods rich in antioxidant vitamins C and E and selenium may help reduce the risk of pancreatic cancer — a poorly understand cancer that’s often diagnosed too late for effective treatment, making prevention especially important. British researchers report that people consuming more dietary vitamins C and E and selenium (but not zinc) were at 67% lower risk for pancreatic cancer than those in the lowest one-quarter of intake. The fact that higher risk was seen only in the lowest intake group suggests a “threshold effect,” scientists commented, beyond which extra antioxidants offered no further protection. If a causal connection is confirmed, however, 1 in 12 such cancers could be prevented by getting more than the lowest level of dietary antioxidants. Researchers compared 49 participants in the large EPIC-Norfolk study who developed pancreatic cancer with 3,970 healthy controls. In contrast to previous negative findings with antioxidant supplements, scientists added, “food sources of these nutrients may have different effects.” — Gut…
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August 2012
If you’re among those watching your grocery bills with a newly sharp eye these days, you might want to think twice about those pricey (and calorie-filled) sports drinks in your cart. A new review of health claims for 104 sports drinks, supplements aimed at athletes, and other products purporting to boost performance or recovery reports slim scientific support for those promises. More than half of the 431 claims made on manufacturers’ websites had no specific scientific research supporting the claims. Among those that did cite supporting studies, 84% of the studies were deemed to have a high risk of bias and 42% were not randomized. Overall, only 3 studies referenced were found to be “high quality and at low risk of bias.” — BMJ…
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June 2012
Supplements of calcium and vitamin D at low doses don’t prevent fractures in otherwise healthy postmenopausal women, according to draft recommendations from an expert task force, and a slight associated increased risk of kidney stones tilts the equation against using the supplements. The recommendations were issued by the US Preventive Services Task Force (USPSTF), appointed by the Department of Health and Human Services. In making the recommendations, the experts relied heavily on findings from the Women’s Health Initiative Study of more than 36,000 postmenopausal women who were given 400 IU of vitamin D and 1,000 mg of calcium. The panel said there was insufficient evidence one way or the other on higher doses for fracture prevention. But the task-force draft came on the heels of a separate USPSTF finding that vitamin D supplements were effective in reducing the risk of falls for peoples over age 75.
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June 2012
A new study of calcium and heart health suggests that a balanced diet is likely the best and safest way to make sure you’re getting enough calcium for your bones. In the study of 23,980 Germans, ages 35-64, those taking calcium supplements were almost twice as likely to suffer heart attacks as those taking no vitamin supplements of any kind. The EPIC-Heidelberg study followed participants for 11 years, during which time 354 suffered heart attacks. Researchers reported that calcium from food, previously thought to protect against cardiovascular disease, showed little benefit. Though the study couldn’t prove that calcium pills contributed to heart-attack risk, the findings were enough for an accompanying editorial to conclude that getting calcium in large doses by supplementation “is not natural, in that it does not reproduce the same metabolic effects as calcium in food. The evidence is also becoming steadily stronger that it is not safe, nor is it particularly effective.” — Heart
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May 2012
A review of the scientific evidence for the National Cancer Institute finds little support for marketing dietary supplements as protection against cancer — and notes that high doses of some supplements can actually add to cancer risk. Most clinical trials of vitamin and mineral supplements against cancer have disappointed, the reviewers concluded. In the review, except for a lone Chinese study, trials of antioxidant supplements, including beta-carotene and vitamins C and E, failed to show anti-cancer benefits. Results for long-term folic acid supplementation versus cancer have likewise been mostly negative. Although some epidemiological studies have linked higher vitamin D levels to lower rates of certain cancers, the review found the evidence insufficient and called for more research on vitamin D. Despite the absence of evidence that supplements prevent cancer (and the possibility of harm), reviewers noted that “marketing claims by the supplement industry continue to imply anti-cancer benefits.” They blamed “insufficient government regulation” of the $30 billion-a-year industry. — Journal of the National Cancer Institute
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April 2012
That “traditional Chinese medicine” you’re thinking of trying for what ails you just might contain some nontraditional — and potentially dangerous — ingredients. Scientists at Murdoch University in Australia used state-of-the-art DNA sequencing to unscramble the complex mix of organic compounds in samples of herbal teas, flakes and powders seized by customs officials. Among the ingredients identified were plants linked to urinary tract and kidney cancer, along with ephedra, banned in US dietary supplements. Some of the 68 different compounds found in 15 herbal medicines are toxic if taken in too large a dose; the packaging failed to list the concentrations of these ingredients. Scientists also discovered traces of animals restricted because of endangered-species concerns. Other animal compounds proved to be adulterated: A remedy labeled as 100% Saiga antelope actually included goat and sheep DNA. Scientists concluded, “Traditional Chinese medicines have a long cultural history, but today consumers need to be aware of the legal and health-safety issues before adopting them as a treatment option.” — PLoS Genetics
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April 2012
Add improved blood-vessel function to the possible health benefits of the omega-3 fatty acids found in fish oil. A new Chinese meta-analysis of 16 prior studies totaling 901 participants found a small but significant improvement in flow-mediated dilation (a measure of a healthy blood vessel’s ability to relax) associated with omega-3 supplementation. The amounts in the supplements ranged from 0.45 to 4.5 g per day; at the lower and medium ranges of omega-3s the blood-vessel benefits increased as the doses increased. Only people with cardiovascular disease or its risk factors benefited, researchers noted, possibly because healthy participants already had sound blood-vessel function. The mechanism by which omega-3s might boost blood-vessel functioning isn’t known, but scientists pointed to studies showing omega-3s might reduce inflammation and cell damage. — Atherosclerosis
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March 2012
In further evidence that it is indeed possible to get too much of a good thing, Japanese scientists have linked extra vitamin E to an increased risk of osteoporosis — if only in mice. The study gave mice doses of vitamin E comparable to what supplements would provide in humans. After 8 weeks, mice given the extra vitamin E showed thinning in their bones. Vitamin E, the scientists explained, stimulates the generation of cells that degrade bones; in normal circumstances, these cells work with bone-building cells to maintain healthy bones. Excess vitamin E, however, may tip the balance to make bones more fragile. The study was conceived after researchers noticed that another group of mice, genetically modified to be deficient in vitamin E, had higher bone densities. — Nature Medicine
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March 2012
Surprising genetic findings have called into question hopes that folic acid might prevent coronary heart disease by lowering homocysteine, an amino acid previously linked to heart disease. British scientists looked at data on more than 100,000 people who’d been tested for a genetic variant, TT, that boosts the body’s homocysteine levels. If lifelong exposure to homocysteine really increased heart-disease risk, the scientists reasoned, then people with the TT variant — whose homocysteine levels average 20% higher than normal — should suffer more heart disease. But no such significant correlation was found. The researchers also analyzed 10 clinical trials testing folic acid to lower homocysteine, and found no benefit against heart disease. Previous findings of a modest benefit from folic acid, they concluded, were “an artifact of publication bias.” An accompanying editorial agreed, saying the new results “argue against the use of folate (folic acid) supplements as a means of reducing coronary heart disease risk.” — PLoS Medicine
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February 2012
It’s important to supplement your aerobic exercises with strength training, using weights or resistance to give your muscles a workout. But now Brazilian researchers suggest that supplementing your strength training, in turn, with the omega-3s found in fish oil could make those exercises work better. Scientists at Paraná Federal University compared muscle strength and functional capacity before and after three months of strength training in 45 senior women. Two groups of women were given two grams daily of fish-oil supplements, with one group starting the pills 60 days before the training began. All the participants showed muscle improvement, but the two fish-oil groups improved more and also performed better in a chair-rising test. Only those getting fish-oil supplements showed improvements in electromechanical measures of muscle performance. Omega-3s have been shown to play a role in the plasma membrane and cell function of muscles, the researchers noted. — American Journal of Clinical Nutrition
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February 2012
That spicy kick from the hot wings at your Super Bowl party may also be kick-starting your body to burn more calories. A new Purdue University review of the scientific evidence reports that capsaicin, the compound that makes chile peppers hot, has "modest" potential for weight management. If you can't stand the heat, there's also good news: Capsiates, similar but non-pungent compounds found in sweet peppers, may also have "thermogenic" effects, boosting calorie burning. The review found consistent evidence that the pepper compounds promote thermogenesis in normal-weight individuals, helping to keep them lean. Four studies also showed similar benefits in overweight and obese people, while two studies found no effect. The reviewers noted that amounts of the pepper compounds varied widely among the studies, from 0.2 mg in a single meal to a tongue-blazing 33 mg a day for 4 weeks, and that other studies tested supplements rather than fiery foods. - Chemical Senses…
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January 2012
Another new study suggests, however, that when it comes to vitamin D and your heart, there may be a “Goldilocks” relationship — you’re healthiest when your vitamin D level is just right. Researchers found that increasing blood levels of vitamin D are associated with decreasing amounts of C-reactive protein (CRP), a marker of inflammation linked to artery stiffness and greater risk of heart problems. But that benefit held only up to a point: Any extra increase in vitamin D beyond what’s considered the low range of normal (21 nanograms per milliliter, ng/mL) actually was associated with CRP going up again. Cautioning that their findings show it is possible to get too much of a good thing, the scientists recommended checking with your doctor before taking vitamin D supplements. Each 100 IU of supplemental vitamin D raises blood levels by about 1 ng/mL. — American Journal of Cardiology
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December 2011
If you’re tempted to try whole-body vibration (WBV) to combat osteoporosis, a new year-long study might give you pause. The electronic therapy has been popularized in recent years following promising results in animals, but studies in humans have shown mixed findings. So Canadian researchers split 202 healthy women into three groups, two of which received WBV treatment at different wavelengths while the third served as a control. All the women were taking calcium and vitamin D supplements to promote bone health. After 12 months, the women’s bone mineral density (BMD) was measured using high-resolution tomography and x-rays. No difference was found in BMD between either whole-body vibration group and the control group, nor did the groups differ in the frequency of clinical fractures during the study. Researchers concluded that WBV “is thus not recommended for preventing age-related bone loss” in healthy postmenopausal women. — Annals of Internal Medicine
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