Supplementation of Protein at Breakfast Rather Than at Dinner and Lunch Is Effective on Skeletal Muscle Mass in Older Adults.

The effects of different intake patterns of meal protein on muscle mass have not been clarified. We cross-sectionally and longitudinally examined the effect of different timing of protein intake on sarcopenia-related factors in older adults. This cross-sectional study 1 included 219 (male, = 69, female, = 150) elderly subjects aged ≥65 years. Subjects who consumed more protein at breakfast than at dinner were grouped into the morning group (MG, = 76; male, = 26; female, = 50), and those who consumed more protein at dinner than at breakfast were grouped into the evening group (EG, = 143; male, = 43; female, = 100). In cross-sectional study 2-1 (female, = 125), the subjects were classified into four groups according to the number of meals with sufficient protein intake. In cross-sectional studies 2-2 (female, = 125) and 2-3 (female, = 27), the subjects were classified into eight groups and three groups according to whether they had consumed sufficient protein at three meals; sarcopenia-related factors were compared. The intervention study was a placebo-controlled, double-blind, randomized controlled trial that included 40 elderly women with low daily breakfast protein intake. The subjects were divided into four groups: morning protein and placebo intake groups and evening protein and placebo intake groups. Each group consumed the test food (containing 10 g milk protein) or placebo in the morning or evening for 12 weeks. Blood indices and physical function were assessed before and after the intervention. Comparing all subjects, MG showed significantly higher handgrip strength than did EG ( < 0.05). The higher ratio of morning protein intake relative to the total protein intake, the better the muscle mass ( = 0.452, < 0.05) and handgrip strength ( = 0.383, < 0.05). The intervention study showed an increase in muscle mass with the intake of milk protein in the morning rather than in the evening ( < 0.05). Protein intake at breakfast might have relatively stronger effects on skeletal muscle mass than at lunch and dinner.