Journal
JOURNAL OF NUTRITION
Volume 147, Issue 2, Pages 195-201Publisher
OXFORD UNIV PRESS
DOI: 10.3945/jn.116.231779
Keywords
muscle protein synthesis; initiation factors; whey protein; egg protein; soy protein
Categories
Funding
- Egg Nutrition Center/American Egg Board grant
Ask authors/readers for more resources
Background: Protein quantity and quality at a meal affect muscle protein synthesis (MPS); however, long-term effects of protein distribution at individual meals on adult muscle mass remain unknown. Objective: We used a precise feeding protocol in adult rats to determine if optimizing postmeal MPS response by modifying the meal distribution of protein, and the amino acid leucine (Leu), would affect muscle mass. Methods: Two studies were conducted with the use of male Sprague-Dawley rats (similar to 300 g) trained to consume 3 meals/d, then assigned to diet treatments with identical macronutrient contents (16% of energy from protein, 54% from carbohydrates, and 30% from fat) but differing in protein quality or meal distribution. Study 1 provided 16% protein at each meal with the use of whey, egg white, soy, or wheat gluten, with Leu concentrations of 10.9%, 8.8%, 7.7%, and 6.8% (wt:wt), respectively. Study 2 used whey protein with 16% protein at each meal [balanced distribution (BD)] or meals with 8%, 8%, and 27% protein [unbalanced distribution (UD)]. MPS and translation factors 4E binding protein 1 (4E-BP1) and ribosomal protein p70S6 (S6K) were determined before and after breakfast meals at 2 and 11 wk. Muscle weights and body composition were measured at 11 wk. Results: In study 1, the breakfast meal increased MPS and S6K in whey and egg treatments but not in wheat or soy treatments. Gastrocnemius weight was greater in the whey group (2.20 +/- 0.03 g) than the soy group (1.95 +/- 0.04 g) (P < 0.05) and was intermediate in the egg and wheat groups. The wheat group had >20% more body fat than the soy, egg, or whey groups (P < 0.05). Study 2, postmeal MPS and translation factors were 30-45% greater in the BD group than the UD group (P < 0.05), resulting in 6% and 11% greater (P < 0.05) gastrocnemius and soleus weights at 11 wk. Conclusion: These studies show that meal distribution of protein and Leu influences MPS and long-term changes in adult muscle mass.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available