Chromium

Chromium is an essential trace mineral in the body that aids insulin in the transfer of glucose, amino acids and fat from the bloodstream into the cells. Chromium can be found in many unrefined foods such as whole-grain breads and cereals, nuts, prunes and mushrooms. The estimated safe range of chromium intake for adults is 50 to 200 micrograms per day. With a typical American diet, two-thirds of the recommended daily allowance (RDA) of chromium is consumed.

Chromium supplementation became popular after it was found that exercise increases chromium loss, raising the concern that chromium deficiency may be common among physically active individuals. Despite little evidence existing to suggest that chromium deficiency is a widespread problem, chromium picolinate (a supplemental form of chromium) has gained popularity recently as a potent stimulus for simultaneous muscular development and fat loss. The few research studies conducted on chromium supplementation have not found it to have a beneficial effect on levels of either lean muscle mass or body fat.

In 1996, the Federal Trade Commission (FTC) forced three of the leading marketers of chromium picolinate to stop making undocumented claims, including that the pills promote weight loss, burn fat, build muscle, lower cholesterol, regulate blood sugars, and treat or prevent diabetes. The FTC concluded that these health claims had not been substantiated by scientific studies, and that no reliable evidence existed that most Americans do not consume enough chromium. In a recent position paper, the American College of Sports Medicine (ACSM) concluded that, "based on available evidence, chromium supplementation is not necessary." ACSM recommends that individuals consume a diet high in unrefined foods and include a wide variety of foods to obtain adequate amounts of chromium.

Creatine

Creatine is one of the "hottest" supplements among fitness enthusiasts. Part of the reason for its popularity is the growing evidence suggesting that taking creatine supplements may improve the ability to perform short-term, intense exercise.

The effect of creatine on short-term, intense exercise is hardly surprising, given the relationship between creatine and skeletal muscle. All skeletal muscle tissue contains creatine, and dietary creatine is found in both meat and fish. In its phosphorylated form, creatine plays a key role in the formation of ATP (the body's energy source) and, during exercise, a portion of the muscle's creatine is depleted. Without sufficient amounts of creatine, which is manufactured in the liver and the kidneys and stored in the skeletal muscles, the cycle that creates this energy is unable to produce enough ATP to meet the demand of short bursts of high-intensity exercise. Creatine supplements have been shown to increase the total creatine content (creatine and creatine phosphate) of muscle on an average of 20 to 30 percent.

Several studies suggest that ingestion of 20 to 25 grams of creatine monohydrate per day for five to six days improves muscular performance during activities that require short periods of high-intensity power and strength (weightlifting, sprinting). Sufficient evidence exists to state that, under certain conditions, creatine supplementation can enhance performance in these activities. If individuals can train at higher intensity levels, they may be able to add strength and power at accelerated rates over a period of time. Creatine can also lead to weight gain, but the mechanism responsible for the added weight has not been adequately investigated. Before individuals start buying and taking creatine supplements, however, they should consider the following:

* Approximately 20 grams per day (four doses of 5 grams each, consumed over the course of the day) should increase muscle creatine levels within five to seven days.

* To encourage the storage of creatine in the muscles, 90 grams of carbohydrates should be consumed with each 5-gram dose.

* A more gradual technique would be to consume 3 grams of creatine a day for approximately one month.

* Two grams of creatine supplementation per day will maintain muscle creatine levels once these levels are full.

* The long-term effects of taking creatine have not been studied. The majority of studies have examined the short-term (30 days or less) effects.

* All of the studies conducted have involved adults only. Creatine's effects on children are unknown.

* Consuming large quantities of creatine (greater than 30 grams per month) may encourage fat to accumulate in the liver.

* Stomach cramping and diarrhea have been cited as adverse side-effects of creatine supplementation.

* Creatine supplementation is not recommended for individuals involved in aerobic endurance activities, since any resultant increase in body-mass levels could impair performance.

The U.S. Food and Drug Administration (FDA) issued the following statement regarding creatine use: "Much remains unknown about whether creatine is absolutely safe for long-term use at levels currently being recommended. Both current and potential users should consult their physicians to identify any potential health problems."

Dehydroepiandrosterone (DHEA)

Dehydroepiandrosterone (DHEA) is secreted by the adrenal glands and converted into testosterone and estrogen. As with many hormones, decreasing amounts of DHEA are produced as the body ages. DHEA production typically peaks around age 30 and steadily declines thereafter. By age 60, DHEA production is reduced to approximately 10 percent of what it was at age 30. Proponents of DHEA claim that it offers the following beneficial effects:

* Stops or slows the aging process

* Stops or slows the development of Alzheimer's disease

* Builds muscle

* Helps individuals lose body weight and fat

* Improves sex drive

* May help treat cancer and AIDS

Unfortunately, all of these claims have one thing in common: None of them have been scientifically documented by well-designed studies. While a relatively large body of research on DHEA has been conducted using animal subjects, these studies have limited value since animals do not mimic human-DHEA lifecycle patterns. In 1996, the FDA banned the sale and distribution of DHEA for therapeutic cases until its safety and effectiveness could be reviewed. To circumvent the ban, manufacturers began marketing and selling DHEA as a nutritional supplement rather than a therapeutic drug.

The most sensible approach to take with a poorly studied supplement such as DHEA is to be extremely cautious. Because DHEA is a natural substance, the FDA has no regulatory power to control its distribution. Manufacturers are allowed to say (or not say) virtually anything they wish concerning their product. A decision whether to take DHEA should be made on the basis of a risk/benefit analysis. At present, little or no evidence exists to support the positive claims associated with DHEA use. While DHEA users have reported few adverse side-effects, one side-effect is irreversible masculinization in women (hair loss, excessive facial hair growth and deepening of the voice). In addition, male users of DHEA have reported irreversible gynecomastia (development of breasts in men), which may be the result of elevated estrogen levels. At present, there are many unknowns regarding the long-term adverse effects of DHEA use. Because of its tendency to cause prolonged elevations of serum estrogen and testosterone levels, DHEA may significantly increase the risk of uterine and prostate cancer.

The potential risks associated with DHEA use appear to substantially outweigh any possible benefits. Given the lack of scientific evidence to support its performance-enhancing abilities and its potentially severe side-effects, DHEA supplementation is not recommended. The National Institute on Aging (NIA) has launched an educational campaign to urge consumers to approach "anti-aging" hormone supplements with caution. Consumers can contact the NIA (800 222-2225) to order a free fact sheet on hormone supplements.

Truth In advertising?

Many nutritional supplements are marketed using deceptive, misleading or downright dishonest claims. Although many of their claims are unsubstantiated, such substances can be marketed without the FDA review of safety and effectiveness. Another problem with these "magic pills, powders and potions" is that the concentration of active ingredients can greatly differ from product to product due to the lack of regulatory control. Although some supplements may confer beneficial effects, most are associated with various adverse side-effects. Fitness enthusiasts and athletes should remain skeptical when considering nutritional supplement use. As the old saying goes, "Caveat emptor: Let the buyer beware."

REFERENCES

Armsey Jr., T.D. Nutrition supplements: Science vs. hype. The Physician and Sportsmedicine 25(6): 77-92, 1997.

Clarkson, P.M. Nutritional supplements for weight gain. Sports Science Exchange 68 by Gatorade Sports Science Institute 11(1), 1998.

Dehydroepiandrosterone (DHEA). Medical Letter on Drugs and Therapeutics 38(985): 91-92, 1996.

Eichner, E.R. Ergogenic aids: What athletes are using and and why. The Physician and Sportsmedicine 25(4): 70-83, 1997.

Lukaski, H.C., W.W. Bolonchuk, W.A. Siders & D.B. Milne. Chromium supplementation and resistance training: Effect of body composition, strength, and trace element status of men. American Journal of Clinical Nutrition 63: 954-965, 1996.

National Institute on Aging. Pills, Patches, and Shots: Can Hormones Prevent Aging? Bethesda, Md., 1997.

Williams, M.H. The Ergogenics Edge: Pushing the Limits of Sports Performance. Human Kinetics: Champaign, Ill., 1998.



James Peterson, Ph.D., FACSM, is a sports medicine consultant, fellow of the American College of Sports Medicine, a former faculty member at the United States Military Academy and a former director of sports medicine for StairMaster Sports/Medical Products Inc.
 

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