A study conducted at Fred Hutchinson Cancer research center in Seattle, Washington evaluated the effect of dietary and supplemental calcium on 10-year weight change in 5250 men and 5341 women from the Vitamins and Lifestyle (VITAL) study. The participants ranged in age from 53 to 57, and completed questionnaires about their supplement use for the 10 years prior to the study and their dietary calcium intake for the immediately preceding year. The subjects’ height, current and previous weights, exercise, smoking history, and demographic characteristics were recorded.

Most individuals in the study were Caucasian and well educated, and all except 8% were nonsmokers. Women in the study had an average dietary calcium intake of 811 mg/day in the year preceding the study, and the average dietary calcium and supplemented calcium totaled 1094 mg/day.

Women who took 500 mg or more of supplemental daily calcium either during the study or during the previous 10 years had a significantly smaller weight gain over those 10 years than women who did not take supplemental calcium. The difference was about 4 lb. Dietary calcium alone was not associated with a smaller weight gain, and calcium intake in men had no effect on weight gain.

Commentary

Previous research has elucidated an inverse relationship between calcium intake and weight gain. This study seems to support that observation. However, the study is limited by the reliability of self-reported body weights and supplement dosing over the 10 year pre-study period. We cannot feel confident that this study provides adequate evidence for recommending either calcium supplements or dairy products to middle aged women as means for achieving weight stability. On the other hand, there are compelling reasons for women to have an adequate calcium and vitamin D intake as they age. Perhaps this will also give them the small benefit of less weight gain during aging.

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

A randomized, double-blind. placebo-controlled trial examined the use of conjugated linoleic acid (CLA) in 118 overweight subjects with a body mass index (BMI of 28-32 kg/m2 . The study subjects were mainly women, and were given 3.4 g/day of CLA or placebo for 6 months. Measurements included total body weight, body fat mass (BFM), and waist size. Women assigned in the CLA group lost 3.4% BFM, while those in the placebo group lost 0.1%. Subjects who complied well with the study protocol had a loss of 5.6% BFM. In women who were obese at the start of the study (BMI > 30 kg/m2 ), most fat loss was from the legs. Waist size in the treatment group decreased by more than 1 inch, or 2.7%, but did not change in the placebo group.

Commentary

The results of this study aren’t surprising in view of previous reports that CLA reduces body weight. The primary mechanism of the effects of CLA on weight loss has not been spelled out in detail, but a reduction in the accumulation of fatty acids in fat cells as the result of inhibition of lipoprotein lipase and promotion of carnitine palmitoyltransferase is the most probable mechanism for this. The legs aren’t a critical area for weight loss, but the waist is. Abdominal fat and abdominal weight gain are highly associated with an increased risk of cardiovascular disease. As CLA is used for one to two years, Other reports suggest that use of CLA for 1-2 years can be accompanied by a decline of 9% in BFM.