University of Hawaii researchers analyzed the nutrient intake of nine male and two female bodybuilders during both contest and off-season periods. Analysis showed low-carb, low-fiber and very high-protein intakes during periods, with protein ranging from 2.2 to 5.2 grams per kilogram of bodyweight; the suggested protein intake for bodybuilding purposes is around 1.7 grams per kilogram of bodyweight. The bodybuilders also showed intakes of calcium, magnesium and niacin that exceeded established tolerance levels. Vitamin B6 levels also exceeded the upper adult-intake tolerance, but only during the precontest phase. Iron intakes averaged 70 to 250 milligrams daily, far in excess of the suggested 10 milligrams for men and 15 for women. Zinc intakes ranged from 30 to 158 milligrams per day; the RDA is 15 milligrams.
The subjects’ nutrient intake came from food, supplements and fortified sports products, such as meal replacements. Based on this initial study, it appears that bodybuilders who use supplements are at risk for nutrient toxicity. Read the labels of the supplements you use to ensure that you aren’t getting too much of potentially toxic nutrients, such as zinc and iron. IM