Exogenous amino acids stimulate human muscle anabolism without interfering with the response to mixed meal ingestion
Supplementing with essential amino acids helps to improve muscle protein synthesis beyond the anabolic efforts of regular food ingestion. The effectiveness of essential amino acids is even greater when combined with carbohydrates. But, if essential amino acid and carbohydrate supplementation interferes with the normal muscle-stimulating response to protein from daily meals or blunts appetite, then the benefits gained from supplementing would be offset.
Acute metabolic study
Number of Subjects
28 - 48
To assess the benefits of a between-meal supplement made up of 30 grams of carbohydrate and 15 grams of essential amino acids and determine if this supplement interferes with the normal metabolic response to a nutritionally mixed meal in healthy, active male participants.
A control group consumed 3 liquid mixed meals and a supplemental group received the same meals with 3 additional supplements containing 30 grams of carbohydrate and 15 grams of essential amino acids. Researchers measured net phenylalanine balance (NB) as an indicator of net gain of body protein, as well as the fractional synthetic rate (FSR) of muscle protein, to determine the metabolic impact of the dietary supplement.
The carbohydrate and essential amino acid supplement (CAA) led to a greater mixed muscle FSR and NB than ingestion of the meals alone.
Findings indicate that supplementing with essential amino acids + carbohydrate stimulates a greater anabolic effect than that produced from a nutritionally mixed meal and does not interfere with the normal metabolic response to a meal.
Aging and circumstances of critical illness are accompanied by a progressive loss of muscle tissue that is made worse by poor diets that don’t provide enough protein, as well as loss of appetite. Supplementing with essential amino acids helps meet these protein needs without compromising appetite or blunting the normal anabolic response to protein from daily meals.
Paddon-Jones D, Sheffield-Moore M, Aarsland A, Wolfe RR, Ferrando AA. Exogenous amino acids stimulate human muscle anabolism without interfering with the response to mixed meal ingestion. Am J Physiol Endocrinol Metab. 2005;288(4):E761-E767. doi:10.1152/ajpendo.00291.2004