The Relationship among Antioxidant Intake, Adiposity, and Aerobic Capacity in an Athlete Population
Authors:   , Werner Emily N. , Volpe Stella L. 
Published: July 2021

There are many factors that contribute to an athlete's performance, including his/her dietary intake, body composition, and aerobic capacity. One purpose of this study was to define fitness characteristics of an athlete population (n = 32, n = 15 male; 35.69 ± 11.34 years of age) and examine sexrelated differences in those characteristics. Characteristics measured included days of self-reported physical activity per week, height, body weight, body mass index (BMI), waist circumference, percent body fat, lean body mass, fat-free mass, maximal oxygen consumption (VO2max), daily kilocalorie (kcal) intake, carbohydrate, protein and fat intake as percent of total kcal, , and antioxidant intake as total amounts and percent of the Recommended Dietary allowance (RDA) or median intake. Percent body fat, lean body mass, and fat-free mass were measured using dual-energy X-ray absorptiometry (DXA). VO2max was analyzed using indirect calorimetry. Data on daily energy, macronutrient, and antioxidant intakes were collected from Block 2005 Food Frequency Questionnaires (FFQs). Antioxidants analyzed included vitamin A, [beta]-carotene, vitamin C, vitamin E, iron, zinc, copper, and selenium. Males were found to have significantly higher values of height (p < 0.001), weight (p < 0.001), BMI (p = 0.025), waist circumference (p < 0.001), lean body mass (p = 0.011), fat-free mass (p = 0.011), and VO2max (p = 0.040) compared to females. Females had significantly more days of self-reported physical activity per week (p = 0.003) and percent body fat (p = 0.011) compared to males. Although males reported significantly higher daily kcal intakes than females (p = 0.007), there were no significant differences between males and females for individual macronutrients as percent of total kcal intake. Males reported significantly higher selenium intakes than females (p = 0.034); however, there were no significant differences for the other seven antioxidants. Males also had significantly higher iron (p < 0.001) and selenium (p = 0.034) intakes as percent of the RDA than females. This study also evaluated the relationships between antioxidant intake and adiposity, antioxidant intake and aerobic capacity, and adiposity and aerobic capacity. No significant relationships were found between antioxidant intake and adiposity or aerobic capacity; however, there were significant negative relationships between percent body fat and VO2max for the total sample (p < 0.001), males alone (p = 0.013), and females alone (p = 0.013). Another purpose of this study was to determine which of the following factors had the greatest effect on aerobic capacity: age, days of self-reported physical activity per week, BMI, waist circumference, percent body fat, lean body mass, or antioxidant intakes (analyzed as percentages of the RDA or median intake). Percent body fat (B = -0.504, p < 0.001), vitamin C intake as percent of the RDA (B = -0.492, p = 0.063), and vitamin E intake as percent of the RDA (B = 2.055, p = 0.154) were the best combination of predictors of VO2max values. Together they explained approximately 51% of the variance (R2 = 0.514, F(3,28) = 0.9.853, p < 0.001). After excluding vitamin C and vitamin E from the model, percent body fat was the greatest singular predictor of VO2max (B = -0.493, p < 0.001; R2 = 0.442, F(1, 30) = 23.799, p < 0.001). In conclusion, antioxidant intakes individually may not be related to measures of adiposity or aerobic capacity in an athlete population. However, when considered in combination, percent body fat, combined with vitamin C and vitamin E, may have considerable effects on VO2max. Further research should consider antioxidant relationships with body composition in the investigation of the antioxidant-mediated exercise benefits.