Effect of a special carbohydrate–protein bar and tomato juice supplementation on oxidative stress markers and vascular endothelial dynamics in ultra-marathon runners

It is well established that exercise induces excessive production of reactive species leading to oxidative stress, which has been implicated in oxidative damage of macromolecules, immune dysfunction, muscle damage and fatigue. The present study examined the effect of supplementation of ultra-marathon runners for a two-months-period with a special whey protein bar containing carbohydrates and protein in a specific ratio (1:1) (N = 16), prepared using as starting material the by-products of cheese manufacturing, and supplementation with commercially available tomato juice (N = 15). Thiobarbituric-acid reactive substances and protein carbonyls were significantly decreased in both supplementation groups, while a pronounced increased in reduced glutathione was observed in the protein bar group. Total anti-oxidant activity remained unchanged in both groups. Flow-mediated dilatation, used as an estimate of endothelial function, was increased in both groups, with a significant rise observed only in the tomato juice administration group. In conclusion, supplementation of ultra marathon runners for a two-months-period with a special protein bar and tomato juice significantly improved the oxidative status of the subjects, while tomato juice also improved vascular endothelial function in these athletes.