Chromium Shows Little Proof as Weight Loss Supplement
January 1998; Volume 1: 9-10
By William D. McArdle, PhD and
Barbara J. Moore, PhD
With the recent decision to pull a popular prescription diet drug combination from the market, physicians with obese patients are sure to face more and more questions about finding ways to help patients lose weight. Given the popularity of pills and other remedies, you need to be aware of some of the solutions your patients may try. A popular "fat burner" is chromium, yet there is no proof that this mineral has any effect on weight loss when patients use it as a supplement, most commonly chromium picolinate. In fact, studies show there is potential for harmful effect in patients who supplement with too much chromium. Following is a discussion of the science surrounding this much-hyped product.Introduction
Chromium, touted as a "fat burner" and "muscle builder," is one of the most hyped minerals in the health food/fitness literature. Supplement intakes of up to 600 mg daily, usually as chromium picolinate, are not uncommon. This chelated picolinic acid combination supposedly improves chromium absorption compared to the inorganic salt chromium chloride. Millions of Americans believe the unsubstantiated claims of health food faddists, television infomercials, and exercise zealots that additional chromium promotes muscle growth, curbs appetite, fosters body fat loss, and even lengthens life.
Nutritional value and mechanism of action
The trace mineral chromium serves as a cofactor for potentiating insulin function in the body, although its precise mechanism of action remains unclear. In all likelihood, some adults consume less than the 50-200 mg of chromium considered the safe and adequate daily dietary intake. This occurs largely because of low intake of chromium-rich foods—brewer’s yeast, broccoli, wheat germ, liver, prunes, egg yolks, apples with skins, asparagus, mushrooms, wine, and cheese.
Clinical studies
One study observed that daily supplementation of 200 mg (3.85 mcmol) of chromium picolinate for 40 days produced a small increase in fat-free body mass (estimated from fatfold thickness) and a decrease in body fat in young men undergoing six weeks of resistance training.1 The body composition data were unreliable, and no data were presented to show muscular strength increases.
Another study reported increases in body mass without changes in strength or body composition in previously untrained female college students (no change in males) receiving daily chromium supplements of 200 mg during a 12-week resistance training program when compared to unsupplemented controls.2
Other research evaluated the effects of chromium supplementation (2000 mg daily) on muscle strength, body composition, and chromium excretion in 16 untrained males undergoing a 12-week resistance training program.3 Muscular strength of both supplemented and placebo groups improved significantly (24% and 33%, respectively) during the training period, with no changes in any of the body composition variables.
The group receiving the supplement did show significantly higher chromium excretion than the controls after six weeks of training. The researchers concluded that chromium supplements provided no ergogenic benefits on any of the measured variables. A large daily supplement of 800 mg of chromium picolinate (plus 6 mg of boron) was no more effective than a maltodextrin placebo in enhancing lean tissue gain or promoting fat loss during resistance training.4 When collegiate football players received daily supplements of 200 mg of chromium picolinate for nine weeks, no changes occurred in body composition and muscular strength from intense weight-lifting training compared to a control group receiving a placebo.5
Among obese personnel enrolled in the U.S. Navy’s mandatory remedial physical conditioning program, the additional intake of 400 mg of chromium picolinate daily caused no greater loss in body weight or percent body fat or increase in lean body mass than did the group receiving a placebo.6 In recent, more comprehensive research, the effect of a daily chromium supplement (3.3-3.5 mmol either as chromium chloride or chromium picolinate) or a placebo for eight weeks in conjunction with a resistance-training program was studied in 36 young men with adequate baseline dietary chromium intakes.5 A double-blind research design insured that neither subjects nor researchers knew who received the supplement. For each group, dietary intakes of protein, magnesium, zinc, copper, and iron equaled or exceeded recommended levels during training. Chromium supplementation increased serum chromium concentration and urinary chromium excretion equally, regardless of its ingested form. In summary, chromium supplementation, regardless of form, produced no added effect on training-related changes in muscular strength, physique, fat-free body mass, or muscle mass compared to placebo treatment.
Adverse effects
Chromium picolinate supplementation produced a significantly greater reduction in serum transferrin (a measure of the adequacy of current iron intake) compared to chromium chloride or placebo treatments. Thus, chromium in picolinate form may adversely affect iron transport and distribution within the body. No studies have evaluated the safety of long-term supplementation with chromium picolinate or the ergogenic efficacy of supplementation in individuals with suboptimal chromium status. Concerning the bioavailability of trace minerals in the diet, excessive dietary chromium inhibits zinc and iron absorption.
Studies in which laboratory cultures of human tissue received extreme doses of chromium picolinate showed eventual chromosomal damage.
Conclusion
In November 1996, the Federal Trade Commission ordered three makers of chromium supplements to cease promoting unsubstantiated weight loss and health claims (reduced body fat, increased muscle mass, increased energy level) for chromium picolinate. Given this action, the lack of clinical data showing any effect on weight loss, and the potential for harmful adverse effects, patients should be advised to avoid this dietary supplement and look toward more traditional weight loss regimens.
References
1. Evans GW. The effect of chromium picolinate on insulin controlled parameters in humans. Int J Biocos Med Res 969;11:163.
2. Hasten DL, et al. Effects of chromium picolinate on beginning weight training students. Int J Sports Nutr 992;2:343.
3. Hallmark MA, et al. Effects of chromium and resistive training on muscle strength and body composition. Med Sci Sports Exerc 996;28:139.
4. Almada A, et al. Effects of ingesting a nutritional supplement containing chromium picolinate and boron on body composition during resistance training. FASEB J 995;9:A1015.
5. Clancy S, et al. Effects of chromium picolinate supplementation on body composition, strength, and urinary chromium loss in football players. Int J Sports Nutr 994;4:142.
6. Trent LK, Thieding-Cancel D. Effects of chromium picolinate on body composition in a remedial conditioning program. NHRC Publication 1995;94-20.
Dr. McArdle is an authority on exercise physiology. Dr. Moore is a nutritionist and President and Chief Executive Officer for Shape Up America! This article is excerpted from Sports and Exercise Nutrition by McCardle, Katch, and Katch, to be published in Spring 1998 by Williams and Wilkins, Baltimore.
CMEQuestions
A 70-year-old man has had stable BPH for several years. He returns to your clinic and states that he wishes to try something to help his urination. He has moderate symptoms and takes no medications. He wishes to avoid surgery. Which of the following should be considered?
a. Terazosin
b. Finasteride
c. Saw palmetto
d. Prazosin
e. All of the above
After reviewing the pros and cons of the medications mentioned in the question above, the patient explains that his insurance does not pay for prescriptions. His income is limited, and he believes he cannot spare more than $15-20 each month. What are his options?
a. Terazosin
b. Finasteride
c. Saw palmetto
d. Prazosin
e. c and d
The active ingredient of hypericum, hypericin, has clinically significant monoamine oxidase inhibitory activity that makes it necessary to be on a tyramine-free diet.
a. True
b. False
There is evidence that individuals with mild-to-moderate depression, especially those with somatic complaints (as may be seen commonly in primary practitioners’ offices), may receive clinical benefit from hypericum.
a. True
b. False
Topical capsaicin stimulates circulation in the area of discomfort, promoting endorphin release.
a. True
b. False
Effects of chromium picolinate supplementation include all of the following except:
a. it potentiates insulin action.
b. it promotes weight loss.
c. in high doses, it may reduce serum transferrin.
d. in extremely high doses, it may cause chromosomal damage.
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