The Science of Supplementation

American Fitness, Jan, 2000 by John A. Wise, Robert O. Voy

Current evidence support the use of nutritional supplements to aid exercise performance and recovery.

While nutritional supplements have been advocated for decades to combat dietary deficiencies, in the past decade they have become an integral part of even mainstream America for assuring daily requirements and enhancing overall health. Advocacy of sports nutrition is a recent phenomenon and we are just beginning to understand its interaction with exercise. With the advent of the Internet, individuals are becoming bombarded by a host of nutritional sports supplements. The following text reviews current research findings regarding the efficacy of nutritional supplements in enhancing exercise and promoting health and fitness.

Essential Vitamins and Minerals

Vitamins and minerals have been established as essential because they cannot be created or synthesized by the human body and must be obtained from dietary sources. All of the major energy-producing reactions in humans have a requirement for these vitamins and minerals, particularly the B vitamin and minerals, while U.S. government surveys indicate that the average diet is consistently deficient in multiple nutrients. Examples include deficient intake of vitamin B1 in four out of 10 individuals, vitamin B6 (three out of 10), folic acid (eight out of 10) and chromium (nine out of 10). Even athletes with apparently adequate diets have been shown to have poor nutrient status when serum or cell levels are measured.

Nutrient deficiencies can have a clear impact on physical performance. As an example, restriction of vitamins B1 (thiamine), B2 (riboflavin) and B6 (pyridoxine) resulted in an overall significant decrease in aerobic power ([VO.sub.2]max; -11.6 percent), peak power (-9.3 percent), mean power (-6.9 percent) and faster onset of blood lactate accumulation ( 12.0 percent). It should be noted that a limited number of studies have shown enhanced performance in athletes when supplemented with single or multiple combinations of vitamins and minerals, while most research has failed to demonstrate clear-cut improvements. However, the positive studies may be reflective of poor nutrient status in the selected subjects.

Since nearly all of the research on human performance has been short-term with protocols over several days to several weeks, the long-term benefits of supplementation have not been adequately recognized. For example, in a recent study on vitamin B6 supplementation, trained athletes exhibited lower plasma levels of free fatty acids, free amino acids, lactate and catecholamines after exhaustive exercise. These results are suggestive of more efficient metabolic processes, which may result in improved training and recovery, thereby translating into increased levels of fitness and performance over the long-term.

Antioxidants, Exercise and Vascular Health

The story of antioxidants has emerged over the past decade as one of the compelling paradigms of health and disease. Risk for heart disease, stroke, cancer, complications of diabetes and aging are all linked to the level of nutritional antioxidants present in our bodies. Since antioxidants protect tissues against dangerous free radicals, which are highly destructive molecules, the dietary intakes determine the relative level of protection. Free radicals are ubiquitous--they can't be avoided because they are generated from environmental pollutants, pesticides, drugs, smoking, UV radiation and normal metabolism. So if metabolism is increased through exercise, more free radicals are produced and more antioxidant protection is needed.

Although exercise is commonly promoted as a health-enhancing activity, it may have a dark side. Kenneth Cooper, M.D., M.P.H., well known as the father of aerobics, now believes that strenuous exercise--such as that associated with triathlons and marathons--can increase the risk for cancer and heart disease. Cooper also believes that antioxidants taken supplementally will combat the negative effects of exercise by protecting cells and tissues against destructive free radicals. Recently, it was discovered that LDL cholesterol particles are more susceptible to oxidative damage following intense exercise. As are well known, antioxidant nutrients such as vitamin E, vitamin C, carotenoids, polyphenol catechins from green tea, anthocyanins from grape skin and grape seed, lipoic acid from soy and coenzyme Q10 can reduce the susceptibility of LDL particles to oxidative damage.

Since the ATP required for effective heart function is derived primarily from mitochondrial respiration--in which coenzyme Q10 plays a pivotal role--it is evident that good coenzyme Q10 status is crucial for optimal cardiovascular performance. This is observed most dramatically in people who surlier from ischemic congestive heart failure or angina. Supplemental coenzyme Q10 typically increases cardiac output, diminishes peripheral resistance, lessens anginal symptoms and improves exercise performance in these individuals. Although fewer studies have examined the impact of coenzyme Q10 on healthy athletes, a double-blind study at the University of Bologna showed that supplemented Co Q10 (100 mg per day for seven weeks) improved the treadmill performance of well-trained male runners, increasing both their endurance time and speed.