5. Conclusions
To the best of our knowledge, our study is the first NMR-based investigation that identified the RBJ intake biomarkers and evaluated their changes induced by physical activity. This study was not aimed at evaluating the metabolic effects of RBJ on performance, which has been often related to the high nitrate content of RBJ and to the physiological effect of nitric oxide. Our study showed a different behavior in the urinary excretion of the identified RBJ intake biomarkers in relation to physical activity. These differences could reflect the physiology of the gastrointestinal system, involving the splanchnic blood flux and/or intestinal permeability, and thus leading to a better passage of molecules. The possibility of influencing through physical activity the adsorption of plant bioactive compounds is very intriguing, since the intestinal transport of these molecules mainly occurs via diffusion processes or paracellular mechanisms.This investigation opens a new perspective on the importance of food bioavailability for human health and athletic performance. It is evident that the effect could depend on the physical exercise intensity and should be further confirmed.