Body composition, dietary intake and supplement use among triathletes residing in the Western Cape Region
Thesis (MNutr(Interdisciplinary Health Sciences. Human Nutrition))--Stellenbosch University, 2008.
Objective: The aim of this study was to determine the body composition, dietary intake and supplement use among training olympic and ironman distance triathletes residing in the Western Cape region. Design: Descriptive, analytical, cross-sectional study design Setting: Western Cape Province (South Africa) Subjects: Triathletes residing in the Western Cape region registered with Triathlon South Africa (N = 26) Outcome measures: Percentage body fat, total energy intake, macro– and micronutrient intake, use and reasons for use of nutritional supplements or nutritional ergogenic aids. Results: The mean age of the men and women was 37.9 [Standard Deviation (SD) 6.82] and 37.5 (9.6) years respectively. The corresponding mean amount of training per week for men and women respectively were 15.1 (4.1) and 15.3 (4.7) hours. The percentage body fat as determined by multi-frequency bio-electrical impedance analysis of the men and women were 12.97% (4.3) and 21.4% (6.3) respectively. The mean dietary macronutrient intake as determined by a three day food record for men was for total energy intake 14 534.7kJ (4509.8), carbohydrate intake 5.3g/kg body weight (BW) (1.9), protein intake 2.0g/kg BW (0.5) and fat intake 34.6% (10.31) of total energy requirements. Dietary micronutrients not reaching 67% of dietary reference intakes (DRI) from food alone included iodine (44%) and fluoride (49%). Vitamin C (154%). Micronutrient intake above upper limit (UL) was sodium (213%), manganese (162%) and niacin (228%). The dietary macronutrient intake for women was for total energy intake 9004.1kJ (2368.8), carbohydrate intake 3.5g/kg BW (1.0), protein intake 1.2g/kg BW (0.2) and fat intake 29.8% of total energy intake (6.0). Micronutrients not reaching 67% of the DRI were chloride (61%), iodine (31%) and fluoride (52%). Micronutrient intake above the UL was vitamin C (218%) and manganese (174%). The dietary intake of the men was inadequate in carbohydrate, provided sufficient energy and protein and excessive fat. The dietary intake of the women was inadequate in total energy and carbohydrate, with an adequate protein intake and excessive fat intake. Although the sample size was very small, some associations were found between dietary intake and clinical health status. Seventy three percent of the triathletes use over the counter dietary supplements. The supplements used most often included carbohydrate supplements (81%), multivitamin and mineral supplements (81%) single vitamins (65%), protein supplements (100%), single minerals (58%), antioxidants (54%) and herbal supplements (42%). Most popular reasons for consuming supplements included recovery (62%), increasing energy supply (61%), enhancing immune function (50%), exercise performance enhancement (46%), increasing muscle mass (54%) and to make up for an inadequate diet or nutrient replacement (31%). Conclusion: Percentage body fat of the men and women were at the upper end of the range associated with elite athletes. The athletes have a fairly good intake of macro– and micro-nutrients. Inadequate habitual carbohydrate intake can be attenuated by the vast majority of the triathletes taking additional carbohydrate supplementation. Supplements were used widely among the athletes, whether it is scientifically proven to be beneficial or not.