Supplementation patterns in marathon runners.

The purpose of the present investigation was to study the use of supplements in a large group of endurance runners (no. = 347) who had participated in the 1987 Los Angeles Marathon. Three-day dietary records were analyzed for nutrient content and supplement usage. The runners' supplementation patterns with respect to demographics, dietary quality, training habits, and race performance were investigated. In general, no significant associations were found between supplement use and the aforementioned variables. Use of supplements, especially vitamins C and E, calcium, and zinc, increased with age (p less than .05). Daily use of at least one type of supplement was reported by 29% of the runners; 48% reported use of at least one type of supplement within the 3-day period.

Nutrient intake of marathon runners.

Three-day food records from a large group of marathon runners (291 men, 56 women) were analyzed and compared to various standards of dietary quality. Intake by the runners exceeded two-thirds of the Recommended Dietary Allowance for all nutrients except vitamin D and zinc in female runners. Energy and nutrient intake levels in the marathon runners were higher than those of the general U.S. population except for total fat, vitamin B-12, and zinc in both men and women and sodium in men. In general, runners consumed better diets than the general population. However, both caloric intake and percent energy as carbohydrate were lower than recommended for individuals engaging in endurance exercise. The need for professional help in planning high-carbohydrate diets for runners is indicated. Increasing amounts of training were not associated with significant increases in nutrient densities across three activity categories within this group of runners. However, more than 75% of the runners perceived their diets to be much improved after they began regular training (men 8.2 +/- 0.3 years of running experience, women 6.7 +/- 0.6). Together, these data suggest that regular moderate-to-heavy endurance exercise is associated with a better quantity and quality of nutrient intake than that found in the general population, which may in part be related to the adoption of such exercise by previously sedentary individuals.