King Grub
2009-03-27, 09:41
Man har tidigare visat att äldre behöver en större mängd leucin i ett EAA-intag för att proteinsyntesen akut skall stimuleras effektivt (vilket inte är fallet hos unga).
BACKGROUND: It has been reported that the blunted muscle protein synthetic response to food intake in the elderly can be normalized by increasing the leucine content of a meal.
OBJECTIVE: The objective was to assess the effect of 3 mo of leucine supplementation on muscle mass and strength in healthy elderly men.
DESIGN: Thirty healthy elderly men with a mean (+/-SD) age of 71 +/- 4 y and body mass index (BMI; in kg/m(2)) of 26.1 +/- 0.5 were randomly assigned to either a placebo-supplemented (n = 15) or leucine-supplemented (n = 15) group. Leucine or placebo (2.5 g) was administered with each main meal during a 3-mo intervention period. Whole-body insulin sensitivity, muscle strength (one-repetition maximum), muscle mass (measured by computed tomography and dual-energy X-ray absorptiometry), myosin heavy chain isoform distribution, and plasma amino acid and lipid profiles were assessed before, during, and/or after the intervention period.
RESULTS: No changes in skeletal muscle mass or strength were observed over time in either the leucine- or placebo-supplemented group. No improvements in indexes of whole-body insulin sensitivity (oral glucose insulin sensitivity index and the homeostasis model assessment of insulin resistance), blood glycated hemoglobin content, and/or the plasma lipid profile were observed. Conclusion: Long-term leucine supplementation (7.5 g/d) does not augment skeletal muscle mass or strength and does not improve glycemic control or the blood lipid profile in healthy elderly males.
Am J Clin Nutr. 2009 Mar 25. Long-term leucine supplementation does not increase muscle mass or strength in healthy elderly men.
http://www.ajcn.org/cgi/rapidpdf/ajcn.2008.26668v1
BACKGROUND: It has been reported that the blunted muscle protein synthetic response to food intake in the elderly can be normalized by increasing the leucine content of a meal.
OBJECTIVE: The objective was to assess the effect of 3 mo of leucine supplementation on muscle mass and strength in healthy elderly men.
DESIGN: Thirty healthy elderly men with a mean (+/-SD) age of 71 +/- 4 y and body mass index (BMI; in kg/m(2)) of 26.1 +/- 0.5 were randomly assigned to either a placebo-supplemented (n = 15) or leucine-supplemented (n = 15) group. Leucine or placebo (2.5 g) was administered with each main meal during a 3-mo intervention period. Whole-body insulin sensitivity, muscle strength (one-repetition maximum), muscle mass (measured by computed tomography and dual-energy X-ray absorptiometry), myosin heavy chain isoform distribution, and plasma amino acid and lipid profiles were assessed before, during, and/or after the intervention period.
RESULTS: No changes in skeletal muscle mass or strength were observed over time in either the leucine- or placebo-supplemented group. No improvements in indexes of whole-body insulin sensitivity (oral glucose insulin sensitivity index and the homeostasis model assessment of insulin resistance), blood glycated hemoglobin content, and/or the plasma lipid profile were observed. Conclusion: Long-term leucine supplementation (7.5 g/d) does not augment skeletal muscle mass or strength and does not improve glycemic control or the blood lipid profile in healthy elderly males.
Am J Clin Nutr. 2009 Mar 25. Long-term leucine supplementation does not increase muscle mass or strength in healthy elderly men.
http://www.ajcn.org/cgi/rapidpdf/ajcn.2008.26668v1