Editor’s note: This is the fourth and final article looking at how dietary supplements affect athletic performance.
There are more than 100 compounds advertised to be supplemental “ergogenic aids,” substances you eat that improve your use of energy, increase energy production, or shorten the time needed to recover from exercise. Of these, only a few actually have any evidence to support their use as performance enhancers. But many are known to be dangerous or potentially harmful.
Previously, I discussed the ergogenic qualities of vitamins and minerals, amino acids and proteins, and caffeine. Used appropriately in moderate amounts, they are generally safe. And some of them can boost athletic performance, especially the vitamins and minerals when an athlete is not getting sufficient amounts from a balanced diet.
Most other supplements do not have a dietary origin, and in fact act like drugs. But unlike control over prescription medications, the U.S. Food and Drug Administration does not have the same regulatory control over supplements.
Ephedra (Ma Huang)
Ephedra and related compounds such as phenylpropanolamine, ephedrine, epinephrine, and phenylephrine don’t enhance athletic performance, nor do they provide any nutritional benefit. Ephedralike substances stimulate the nervous system, increase heart rate and blood pressure, and speed up the metabolism. They are considered illegal substances by the IOC and National Collegiate Athletic Committee. Ephedra was banned by the FDA in December 2003. Athletes have died from taking amphetaminelike substances.
Drugs related to ephedra are used in asthma treatment, but even if prescribed can disqualify an athlete. Athletes with asthma competing at the highest levels need to inform the sports association of the medications they are taking. The athletes must be certain that none of their medications, including inhalers, is on the list of banned substances. Many of the over-the-counter asthma sprays contain banned substances.
If you have asthma but exercise noncompetitively, good control of the condition with medications means more enjoyment of exercise and better performance.
Andro (androstenedione)
Despite the claims, “andro” doesn’t build muscle mass or enhance athletic performance. It may boost testosterone levels a bit, but most of the supplement is converted to the female hormone estrone, a form of estrogen. As an estrogen booster, andro can increase breast size (called gynecomastia). In addition, the supplement increases heart-attack risk, lowers HDL (good) cholesterol and promotes acne. Over the long term, it can increase the size of the prostate gland. The FDA recently sent letters to 23 companies requesting them to stop distributing supplements containing andro. Andro is a banned substance for competition at the amateur level and also for many professional sports.
DHEA (Dehydroepiandrosterone)
DHEA is a naturally occurring steroid made primarily in the adrenal glands. DHEA tends to fall as we age, and one study showed that DHEA given to older men improved strength in some. This one piece of evidence has been wrongly applied to younger people, especially athletes. The reality is that DHEA isn’t effective in improving athletic performance or strength training. Side effects of DHEA are unknown. Because DHEA can be converted to testosterone and estrogen, DHEA may result in problems similar to those of andro. In addition, researchers recently discovered that DHEA increases the blood level of a substance associated with prostate enlargement.
Coenzyme Q10
Coenzyme Q10 is one of the key enzymes that are essential to energy production inside the body’s cells. Within each cell, coenzyme Q10 resides in the mitochondria, the powerhouse of aerobic metabolism. Since this is a natural energy booster inside all cells, it’s easy to understand why people would be excited about a coenzyme Q10 supplement. But after many years of trying, scientists have been unable to show any performance-enhancing benefit when it is taken by mouth. Reports of side effects are rare.
Dr. Howard LeWine is a member of the Harvard Medical School faculty and practicing internist with Harvard Vanguard Medical Associates, and Brigham and Women’s Hospital, Boston. He serves as chief medical editor of internet publishing at Harvard Health Publications.
