L-isoleucine is one of the proteinogenic amino acids that aids in the production of protein. It is a branched chain amino acid (BCAA) that is classified as a hydrophobic amino acid. One of its main benefits is increased strength and rapid muscle repair when combined with other amino acids. As it is an essential amino acid, it can only be obtained from dietary sources and supplements. Both a deficiency and an overdose can result in negative side effects.
The synthesis of L-isoleucine takes place in plants from pyruvic acid, alpha-ketoglutarate, and certain enzymes. Therefore, the original source for this amino acid is found in many plant-based foods, particularly in nuts and seeds, legumes, and grains. Animals cannot synthesize the amino acid, but they can absorb it and form it into proteins. As a result, it is found in high concentrations in animal products, such as meat, dairy, and eggs.
It is important for individuals who engage in regular exercise and bodybuilding to consume sufficient amounts of L-isoleucine because it helps to prevent muscle tissue deterioration during workout sessions. It increases strength and endurance and also helps to speed up the muscle repair after the workout. L-isoleucine supplements are a great way to ensure sufficient amounts are taken; however, they should always be taken in conjunction with L-leucine and L-valine, which are the other two BCAAs. The three amino acids work together and make up about one third of the protein in muscle tissues. Therefore, when taking supplements, it is important to choose one that contains all three.
The amino acid is also beneficial for children and teens who are in their growing years because it is vital for healthy growth. Other benefits of L-isoleucine include normal blood sugar levels, increased production of hemoglobin, and formation of blood clots. A deficiency can result in similar symptoms such as hypoglycemia, which includes weakness, hunger, and dizziness. It can also result in neurological and cognitive problems as well as in depression.
Regardless of the benefits, L-isoleucine can also have negative effects on the body if it is taken in excess amounts. L-isoleucine is metabolized by enzymes, but when enzyme levels are low, the amino acid can build up in the bloodstream. This can potentially result in branched chain ketoaciduria, also known as maple syrup urine disease. Children and those who are pregnant should not take L-isoleucine supplements unless directed by a physician.