Which of the following essential amino acids are classified as branched-chain amino acids (BCAAs)?

The classification of branched-chain amino acids (BCAAs) specifically includes isoleucine, leucine, and valine. These three amino acids share a common characteristic of having a branched molecular structure, which differentiates them from other essential amino acids. BCAAs play crucial roles in muscle metabolism, serving as an energy source during exercise and helping to stimulate protein synthesis.

Leucine, in particular, is known for its role in initiating the process of muscle protein synthesis and is beneficial for recovery and growth. Isoleucine and valine also contribute to efficiency in energy production and recovery processes, highlighting the significance of these amino acids in athletic performance and overall muscle health. This understanding reinforces why the identification of isoleucine, leucine, and valine as BCAAs is vital for those studying sports nutrition.

The other options include amino acids that are either non-essential or do not fall under the branched-chain category, which is why they are not correct choices in this context.