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Besides being a source of information about calcium, vitamin D, and weight gain, the Vitamins and Lifestyle (VITAL) study yielded other data on dietary supplements. In the VITAL study, 15,655 men and women completed questionnaires about their 10-year use of supplements, dietary and health habits, height, former body weights, and present weight.

Among overweight or obese participants, long-term use of a multiple vitamin/mineral, vitamins B6 and B12, and chromium were significantly associated with smaller weight gains. Obese men who took chromium at < 150 mcg/day for the 10 years preceding the study had a weight gain of 6.1 pounds, versus 11.7 pounds for nonusers of chromium, while those who took > 150 mcg/day for the previous 10 years had a weight loss of 3.1 lb. Among obese women, women who used chromium at < 150 mcg/day had a weight gain of 7.9 lb, versus 14.1 for nonusers, and those taking > 150 mcg/day had a weight loss of 3.2 lb.

Other supplemental nutrients, in addition to the multiple vitamin/mineral supplements, were associated with smaller weight gains at higher doses among obese women were coenzyme Q10, ginkgo, ginseng, garlic, omega 3 fatty acids and melatonin.

Nachtigal M, Patterson R, Stratton K, et al. Dietary supplements and weight control in a middle-age population. J Alternative and Complementary Medicine 2005;11(5): 909-915

Commentary

The findings in this study are encouraging for overweight and obese women (and men). It is not surprising to see chromium on the list of nutritional supplements associated with weight loss. Chromium has been previously tested in randomized trials, and a meta-analysis reported a small but statistically significantly greater weight loss in subjects taking chromium than in controls.

Several of the supplements associated with smaller weight gains, and even small weight losses, such as vitamins B1 and B12 and coenzyme Q10,probably exert this effect through their roles as important cofactors in metabolism. The effect of chromium on weight may be due to its enhancement of blood glucose utilization and insulin sensitivity.

The main weakness of this study was its observational format, with a dependence on subjects’ recall of their actions during the 10-year period preceding the study. It is also possible that subjects who showed smaller weight gains or who lost weight had made efforts toward these goals independent of their use of supplements, but the study design did not control for caloric intake or exercise. Nevertheless, limited research suggests that other supplements may be efficacious in limiting or preventing weight gain. These would include CLA, as well as green tea and other herbs containing caffeine.

Before nutritional supplements can be validated as useful and reliable means toward weight maintenance and loss, longitudinal studies and randomized trials of their effects on these goals are sorely needed. And even if supplements are shown to have bariatric efficacy, physical activity and sensible eating are likely to remain the best keys to weight control

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