Effect of dietary intake on subjective condition of and oxidative stress in endurance‐trained athletes

Abstract

The purpose of this study was to investigate the effect of dietary intake on the subjective condition of and oxidative stress in endurance‐trained athletes. Twenty‐four endurance‐trained male runners were recruited. Their average age was 19.8±1.4 years old. Their average running distance was 368.8±160.7km/month. Their dietary intake was assessed by using the food frequency questionnaire based on food groups (FFQg). A visual analog scale was completed for the evaluation of fatigue, tiredness, physical condition, slump level, and endurance in training. The amount of urinary 8‐hydroxy deoxyguanosine (8‐OHdG) excretion was evaluated as a marker of oxidative stress with respect to deoxyribonucleic acid (DNA) damage. We examined the relationship among dietary intake, subjective condition and 8‐OHdG. No one ingested either the estimated energy requirements or the recommended dietary allowance of all nutrients. No relationship between dietary intake and subjective condition was found. Fruit, and fruit and vegetable (FV) negatively correlated with 8‐OHdG (Fruit: R2=‐.420, p=.037, FV: R2=‐.453, p=.026). Beta‐carotene had a tendency to negatively correlate with 8‐OHdG (R2=‐.400, p=.053). We concluded that dietary intake did not affect the subjective condition. However, the antioxidant effect of carotenoid in fruit may have contributed to the decrease in 8‐OHdG.