The Importance Of Isoleucine

L-Isoleucine is a neutral, genetically coded amino acid. It is essential in human nutrition. Isoleucine is found in especially high amounts in meats, fish, cheese, most seeds and nuts, eggs, chickens and lentils. In the human body Isoleucine is concentrated in the muscle tissues. Isoleucine is necessary for hemoglobin formation and in stabilizing and regulating blood sugar and energy levels. A deficiency of isoleucine can produce symptoms similar to those of hypoglycemia.

It is one of several essential amino acids needed in the diet; human beings cannot synthesize it from simpler metabolites. Young adults need about 20 mg of this amino acid per day per kg (or about 8 mg per lb) of body weight. Isoleucine can be degraded into simpler compounds by the enzymes of the body.

It is used in the body to produce certain biochemical compounds that help in energy production and has been found experimentally to reduce twitching and tremors in animals. The branched-chain amino acids (BCAA)?isoleucine, leucine, and valine?have been used as supplements for body (muscle) building.

Both aerobic exercise and strength training increase protein requirements although they do so for different reasons. During aerobic exercise, AAs can be used for energy production (especially the branch-chain AA's, leucine, isoleucine, and valine) and may provide up to 10% of the total energy produced during long-duration activity.

Chronic renal failure (CRF) patients on hemodialysis have low plasma level of the branched chain amino acids (BCAA) leucine, isoleucine, and valine. The abnormalities in the plasma amino acid pool can be corrected with appropriate high-protein supplements. The present study was designed to evaluate the effect of a balanced protein nutritional supplement on the plasma level of BCAA...The plasma BCAA levels were maintained high until the sixth month from the beginning of trial and even a month after withdrawal of the supplement. The results obtained allow us to recommend inclusion of protein supplements with balanced amino acid content in the diet of these patients.

  • Peter Lemon. Is increased dietary protein necessary or beneficial for individuals with a physically active lifestyle. Nutr Rev (1996) 54: S169-S175.
  • Vuzelov E, Krivoshiev S, Ribarova F, Boyadjiev N. Plasma levels of branched chain amino acids in patients on regular hemodialysis before and after including a high-protein supplement in their diet. Folia Med (Plovdiv) 1999;41(4):19-22
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