Author
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Lukaski, Henry |
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Siders, William |
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Penland, James |
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Submitted to: Journal Of The American Dietetic Association
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 12/2/2006 Publication Date: 3/1/2007 Citation: Lukaski, H.C., Siders, W.A., Penland, J.G. 2007. Chromium picolinate supplementation in women: effects on body weight, composition, and iron status. Nutrition 23:187-195. Interpretive Summary: Although chromium is considered to be a nutrient because of its potential role in facilitating insulin action, controversy remains about claims that it promotes weight regulation. A few questionable studies report that chromium, principally the supplement chromium picolinate, foster loss of body weight and fat while increasing lean body mass. One confounding factor is the lack of control of food intake in previous studies. We conducted a randomized, controlled study of the effects of chromium picolinate (~200 micrograms of chromium daily), picolinic acid in an amount similar to that in the chromium picolinate, and placebo in 83 women fed whole-food diets containing the recommended chromium intake for 12 weeks. Body composition, blood indicators of health, and blood and urinary chromium were measured before and during this supplementation trial. Women in all treatment groups lost weight (<2%) and fat with no effect on lean body mass. No independent effect of chromium supplementation was found. We also examined the effects of chromium supplementation on iron nutritional status. Iron status was maintained in all groups with no changes attributable to chromium. These findings show for the first time that chromium supplementation had no beneficial effects on body weight or composition of women fed controlled energy and nutrient intakes. This information will be useful to dietetics professionals who advise people on proper use of dietary supplements. It also will benefit regulatory agencies, such as the Federal Trade Commission and the Food and Drug Administration that review claims for health promotion and advertising of dietary supplements. Technical Abstract: Objective: Supplementation of chromium as chromium picolinate (CrPic), 200 µg Cr/d, is claimed to promote weight loss and propitiously affect body composition; it may adversely affect iron status. This study tested the hypothesis that supplementation of CrPic, compared to an equivalent amount of picolinic acid (PA) in CrPic and placebo (P), decreases body weight, alters body composition and reduces iron status of women fed diets of constant energy and nutrients. Design: Eighty-three healthy women (19-50 y) received nutritionally balanced diets composed of Western foods for 12 wk in a double blind, randomized controlled trial. The diets contained 29±5 µg Cr/d by analysis. During an initial 2-wk period, food intake needed to establish individual energy needs to maintain body weight was determined. The women were matched by body mass index and transferrin and randomized to receive supplements containing 200 µg of Cr+3 as CrPic (n=27), 1720 µg of PA (n=27), or P (n=29) for 12 wk. They resided in their homes and maintained their usual activity levels. Body composition was determined and fasting venous blood was analyzed for Cr and iron; timed 24-hr urine samples were analyzed for Cr. Results: CrPic supplementation increased (p<0.0001) serum Cr concentration and urinary Cr excretion compared to PA and P. CrPic did not affect body weight or fat, although all groups lost (p<0.05) weight and fat; it did not affect fat-free, mineral free mass or measures of iron status. Conclusion: Under conditions of controlled energy intake, CrPic supplementation of women did not independently influence body weight or composition or iron status. Thus, claims that supplementation of 200 µg Cr as CrPic promotes weight loss and body composition changes are not supported. |
