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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. [ABSTRACT FROM AUTHOR]

The purpose of the present study was to establish the prebiotic effect of a new xylo-oligosaccharide (XOS) and of an inulin-and-XOS mixture (INU–XOS) and to determine their effect on endotoxaemia (lipopolysaccharides (LPS)) and immune parameters. In this randomised, parallel, placebo-controlled, double-blind study, sixty healthy volunteers were randomly assigned to three groups, receiving either 5 g XOS, INU–XOS (3 g inulin +1 g XOS) or an equivalent weight of wheat maltodextrin (placebo) during 4 weeks. Faecal samples were collected to assess the effects of these products on microbiota, as well as SCFA composition, enzymatic activities and secretory IgA production. Circulating LPS was measured in plasma samples, and whole blood was incubated with LPS to measure cytokine expression. Consumption of XOS alone increased the faecal concentrations of Bifidobacterium and butyrate and activities of α-glucosidase and β-glucuronidase, while decreasing the concentrations of acetate and p-cresol. Consumption of XOS in combination with inulin did not decrease the concentrations of acetate and p-cresol, but increased in addition the faecal concentrations of total SCFA and propionate. Furthermore, consumption of XOS in combination with inulin decreased LPS concentrations in blood and attenuated LPS-induced increases in gene expression in IL-1β and LPS-induced decreases in gene expression in IL-13 in blood. In conclusion, consumption of XOS alone or in combination with inulin results in beneficial albeit different changes in the intestinal microbiome on a high-fat diet. In addition, consumption of XOS in combination with inulin attenuates the proinflammatory effects of a high-fat diet in the blood of healthy subjects. [ABSTRACT FROM PUBLISHER]