BODYBUILDING & TRAINING
Chromium and active people
Compiled by dr Jacques Rossouw
DSc (Biochemistry), BSc Hons (Pharmacology), MBA
Chromium is an essential trace element required for normal carbohydrate, protein, and fat metabolism. Most fresh foods and minimally processed foods are good sources of dietary chromium. The biological function of organic chromium is closely associated with that of insulin and most chromium-stimulated reactions are also insulin dependent. Proper chromium nutrition leads to a decreased requirement for insulin and also a lowering of cholesterol and triglycerides.
Biologically active chromium functions in a number of physiological reactions, especially those that occur in the peripheral tissue e.g. glucose uptake, oxidation of glucose to carbon dioxide, and the incorporation of glucose into fat. Anderson1 has pointed out that chromium may be an example of a trace element that is present at sub-optimal levels in most diets. According to Anderson, sub-optimal dietary chromium may explain the decrease in tissue chromium observed with age and may be related to the high incidence of diabetes and cardiovascular problems in developed countries whose people tend to consume large amounts of processed foods. Since our diet may not contain sufficient chromium, it is likely that athletes also might be ingesting less than adequate amounts. Several studies from the same laboratory have shown that stress, such as exercise, increases chromium losses. Increased excretion of chromium in the urine was reported after a strenuous run. Therefore, Anderson believes that strenuous exercise may increase the need for chromium in humans. Furthermore, additional data shows that high carbohydrate intake, particularly the ingestion of simple sugars, also causes an increased excretion of chromium. Many athletes ingest high-carbohydrate diets and supplement their diets with carbohydrate drinks and bars.
Athletes need chromium
Chromium deficiency could be a problem for both endurance- and strength athletes. In a review on chromium supplementation, published in the International Journal of Sport Nutrition, Lefavi2 speculated that athletes might incur a negative chromium balance under the following conditions:
increased intensity and duration of training may increase chromium excretion;
athletes who ingest high-carbohydrate diets may need more chromium to process glucose; and
athletes who decrease their food intake in an attempt to lose weight may in the process decrease their dietary intake of chromium.
Chromium deficiency signs include excessive or cold sweats, cold hands, dizziness, diabetes (particularly adult onset), excessive thirst, craving for sweet foods, chronic fatigue, arteriosclerosis and mood swings.
Chromium versus anabolic steroids
Chromium supplementation might benefit the endurance athlete by improving insulin sensitivity and carbohydrate metabolism during exercise.3 Also, since insulin is involved in the transport of amino acids into the muscle cells, it is thought that chromium increases this transport and promotes protein synthesis. Two early reports by Evans,4 demonstrating that chromium supplements enhanced lean muscle mass in resistance-trained athletes, spawned a widespread interest in chromium supplements. These studies spurred the notion that chromium may be the 'healthy' answer to anabolic steroids. But, subsequent studies incorporating more appropriate methods to determine body composition have failed to demonstrate any beneficial effects of chromium supplementation on lean body mass, body fat or strength. Therefore, the jury is still out on whether or not chromium supplements deliver an anabolic (building-up) effect on muscle tissue.
It is always advisable for any individual, including athletes, to follow a balanced diet that includes all the essential nutrients. The following are excellent sources of chromium: organ meats (liver, kidneys), shellfish, cheese, nuts, wholegrain products, wheat germ, broccoli, legumes, mushrooms and brewer's yeast. If, however, you train very hard and/or do not follow a balanced diet, it might be wise to choose a nutritional supplement that incorporates chromium into its formula.
1. Anderson RA. Nutritional role of chromium. The Science of the Total Environment 1981; 17: 18-29.
2. Lefavi R. Efficacy of chromium supplementation in athletes: Emphasis on anabolism. International Journal of Sport Nutrition, 1992; 2: 11-122.
3. Williams MH. Nutrition for Fitness and Sport. Fourth ed. Dubuque: Brown & Benchmark Publishers, 1995; p. 229.
4. Evans G. The effect of chromium picolinate on insulin controlled parameters in humans. International Journal of Biosocial and Medical Research 1989; 11: 163-180.
Glycemic Index: blood sugar, energy and mood swings