[Microgravity and weightlessness: experimental model accelerates nutritional pathology].
Short space flights affect nutritional intakes, body composition and functional parameters. Prolonged space flights (SF) over weeks or months further worsen these alterations and result in acute or chronic physical deterioration at earth return. Current planning of SF to Mars, with microgravity conditions for more than 2 years, stresses the need for developing and optimising a nutritional program and physical countermeasures to prevent body mass atrophy and functional body alterations. This review presents the models of microgravity simulation on earth and the main effects of weightlessness on body composition, protein metabolism, hormonal profile and muscle function. It summarizes contradictory findings related to the oxidative stress related to SF. It discusses potential countermeasures (nutrition, physical activity) to the negative effects of microgravity on human body. Future research possibilities in ground and space medicine are evoked.