Intake of fish and omega‐3 (n‐3) fatty acids: effect on bone during actual and simulated weightlessness

Abstract

Space flight has many negative effects on human physiology, including bone and muscle loss. These are some of the systems on which intakes of fish and n‐3 fatty acids have positive effects. These effects are likely to occur through inhibition of inflammatory cytokines (such as TNFα) and thus inhibition of downstream NF‐κB activation. We documented this effect in a 3D cell culture model, where NF‐κB activation in osteoclasts was inhibited by eicosapentaenoic acid, an n‐3 fatty acid. We have extended these studies and report here (a) NF‐κB expression in peripheral blood mononuclear cells of Space Shuttle crews on 2‐wk missions, (b) the effects of n‐3 fatty acid intake after 60 d of bed rest (a weightlessness analog), and (c) the effects of fish intake in astronauts after 4 to 6 mo on the International Space Station. After Shuttle flights of ~2 wk, NF‐κB p65 expression at landing was increased (P <0.001). After 60 d of bed rest, higher intake of n‐3 fatty acids was associated with less N‐telopeptide excretion (Pearson r = −0.62, P < 0.05). Higher consumption of fish during flight was associated with higher bone mineral density (Pearson r = −0.46, P < 0.05). Together with our earlier findings, these data provide mechanistic cellular and preliminary human evidence of the potential for n‐3 fatty acids to counteract bone loss associated with spaceflight. This study was supported by the NASA Human Research Program.