Effect of branched-chain amino acids on food intake and indicators of hunger and satiety- a narrative summary

Abstract

Branched-chain amino acids (BCAA) found in protein are most notably known for their ability to increase protein synthesis, explaining their appeal to athletes seeking muscle hypertrophy, expedited recovery, and preservation of lean body mass. In addition to anabolic benefits, protein consumption has been implicated in the regulation of food intake, which represents an important variable in treating and preventing obesity. Protein-rich foods (such as dairy) have previously been linked to improved satiety and reduced food intake, however, there appear to be discrepancies in the effects of different protein types (for example whey versus casein) on appetite. One potential explanation for these differences is the varied amino acid composition of each protein type. Thus, one theory is that high levels of BCAA may be responsible in-part for the satiating properties of protein. Therefore, the purpose of this narrative review is to describe the effects of BCAA (both individually and in combination) on hormonal regulators of satiety including ghrelin, leptin, peptide tyrosine tyrosine (PYY), cholecystokinin (CCK), and glucagon-like peptide-1 (GLP-1). This report also summarizes the effect of BCAA on food intake and subjective measures of hunger. Several reports suggest BCAA stimulate leptin activity (secretion or sensitivity) and GLP-1 levels and suppress ghrelin levels. Similarly, intake is reduced, and subjective measures of hunger are often lower following consumption of BCAA. However, inconsistencies in experimental protocols and related findings make the true effect of BCAA on satiety and food intake difficult to discern, and therefor worthy of further investigation.

Keywords

• Ghrelin
• Isoleucine
• Leptin
• Leucine
• Peptide-YY (PYY)
• Valine