Dietary Protein Distribution Positively Influences 24-h Muscle Protein Synthesis in Healthy Adults

• Published in: The Journal of nutrition Vol. 144; no. 6; pp. 876 - 880
• Main Authors: Mamerow, Madonna M., Mettler, Joni A., English, Kirk L., Casperson, Shanon L., Arentson-Lantz, Emily, Sheffield-Moore, Melinda, Layman, Donald K., Paddon-Jones, Douglas
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Elsevier Inc 01.06.2014; American Society for Nutrition
• Subjects: Adult; Biological and medical sciences; Body Mass Index; Cross-Over Studies; Diet; Dietary Carbohydrates - administration & dosage; Dietary Proteins - administration & dosage; Dietary Proteins - pharmacokinetics; Energy Intake; Feeding. Feeding behavior; Female; Fundamental and applied biological sciences. Psychology; Healthy Volunteers; Humans; Male; Meals; Middle Aged; Muscle Proteins - biosynthesis; Nutrient Requirements and Optimal Nutrition; Phenylalanine - blood; Quadriceps Muscle - metabolism; Tissue Distribution; Vertebrates: anatomy and physiology, studies on body, several organs or systems; EVEN; ITS-CRC; FSR; SKEW; Muscle; Nutrition; Protein synthesis; Protein; Distribution
• ISSN: 0022-3166; 1541-6100; 1541-6100
• DOI: 10.3945/jn.113.185280

The RDA for protein describes the quantity that should be consumed daily to meet population needs and to prevent deficiency. Protein consumption in many countries exceeds the RDA; however, intake is often skewed toward the evening meal, whereas breakfast is typically carbohydrate rich and low in protein. We examined the effects of protein distribution on 24-h skeletal muscle protein synthesis in healthy adult men and women (n = 8; age: 36.9 ± 3.1 y; BMI: 25.7 ± 0.8 kg/m2). By using a 7-d crossover feeding design with a 30-d washout period, we measured changes in muscle protein synthesis in response to isoenergetic and isonitrogenous diets with protein at breakfast, lunch, and dinner distributed evenly (EVEN; 31.5 ± 1.3, 29.9 ± 1.6, and 32.7 ± 1.6 g protein, respectively) or skewed (SKEW; 10.7 ± 0.8, 16.0 ± 0.5, and 63.4 ± 3.7 g protein, respectively). Over 24-h periods on days 1 and 7, venous blood samples and vastus lateralis muscle biopsy samples were obtained during primed (2.0 μ mol/kg) constant infusion [0.06 μ mol/(kg⋅min)] of L-[ring-13C6]phenylalanine. The 24-h mixed muscle protein fractional synthesis rate was 25% higher in the EVEN (0.075 ± 0.006%/h) vs. the SKEW (0.056 ± 0.006%/h) protein distribution groups (P = 0.003). This pattern was maintained after 7 d of habituation to each diet (EVEN vs. SKEW: 0.077 ± 0.006 vs. 0.056 ± 0.006%/h; P = 0.001). The consumption of a moderate amount of protein at each meal stimulated 24-h muscle protein synthesis more effectively than skewing protein intake toward the evening meal.