Abstract: Background: The muscle protein synthetic response to food intake is reduced in aging, contributing to a progressive muscle loss. This anabolic resistance results from a decreased sensitivity to anabolic signals, especially leucinemia, a potent activator of protein synthesis. Nutritional strategies are needed to reach the anabolic threshold of leucinemia and stimulate muscle anabolism. Objectives: This study sought to evaluate the effect of supplementing meals with soluble milk proteins (SMP) on postprandial leucinemia in elders. Methods: During 3 successive experimental sessions, 6 healthy older men (66.7 ± 0.7y) consumed a standardized lunch (27 g of proteins; 2.2 g of leucine) supplemented with a…beverage containing 0 g, 5 g or 8.2 g of SMP (0 g, 0.6 g and 1.1 g of leucine, respectively). Results: The supplementation with 5 g or 8.2 g of SMP induced an increase of 1.9× and 2.5× in plasma leucine levels, compared to the control meal (without additional SMP). The leucine area under the curve over 3h20 had an increase of 2.1× and 2.3×, respectively, as compared to the control meal. Conclusions: Ingesting SMP in addition to a meal strongly increased postprandial plasma leucine, and could be an effective strategy to reach anabolic thresholds and optimize the anabolic effect of each meal.
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