Isoleucine is an essential amino acid in humans, meaning the body cannot synthesize it, and must be obtained from our diet.
Like leucine and valine, isoleucine is a branched-chain amino acid (BCAA). They are the only amino acids that can be used as energy source by our muscles during exercise without the help of the liver.
Amino acids are the building blocks of proteins. Most proteins in the human body are composed of 21 amino acids.
Isoleucine contributes to many bodily functions, including:
Isoleucine promotes protein synthesis and turnover.
Isoleucine promotes white blood cell growth and proliferation.
Isoleucine plays a role in neurotransmitters synthesis in the brain (1).
Recommended Daily Allowance for a 44-year-old male moderately active, weighting 70 kg and 175 cm tall is 2.3 g (2).
Do you want to know your personal recommendations ?
The FNB (Food and Nutrition Board of the Institute of Medicine) set its recommendations for isoleucine at 25 mg per gram of proteins (3).
They also recommend that proteins intake for most people should be between 10 % and 30 % of total Calories. This is called the “adequate macronutrient distribution range” (AMDR) and is based on decreasing risk of chronic disease and providing adequate intake of other nutrients.
In our app, the default value is set at 15 % of total calories, which is inside the AMDR and bases on complementing the values for carbohydrates and fats.
To get your isoleucine recommendation expressed in gram, we combine the above recommendations.
The FNB did not establish an upper limit because adequate data from human or animal studies were lacking. This does not mean that there is no potential for adverse effects resulting from high intakes of isoleucine from dietary supplements. Since data are limited, caution may be warranted.