A recent study published in the Journal of Nutrition has found that the branched chain amino acid L-isoleucine has a remarkable effect on obese mice. The researchers found that supplementation with L-isoleucine improved the glucose-lowering effects of insulin, reduced fat deposits and increased fat metabolism.
Mice were fed a very high fat diet for the entire duration of the 6 week trial. After the first 2 weeks, the mice were divided into 2 groups. One group had L-isoleucine added to their drinking water, the other did not. The results were quite impressive:
Those mice who drank water containing 2.5% isoleucine had:
- 49% less epididymal white adipose tissue (WAT) or the type of fat designed to store energy,
- Almost 6% less weight gain at the end of the study,
- 38% less fat in the liver
- 47% less fat in the skeletal muscles &
- 39% less insulin resistance
There was also a decrease in the amount of leptin, the hunger hormone, in the WAT of those mice who received L-isoleucine supplementation and an increase in some other metabolic parameters in the liver and skeletal muscle which influence healthy metabolism.
The researchers concluded that L-isoleucine may be of use in the treatment of metabolic syndrome in humans and called for clinical trials to further investigate this.
Nishimura J, Masaki T, Arakawa M, Seike M, Yoshimatsu H. Isoleucine prevents the accumulation of tissue triglycerides and upregulates the expression of PPARalpha and uncoupling protein in diet-induced obese mice. J Nutr. 2010 Mar;140(3):496-500. Epub 2010 Jan 20 http://jn.nutrition.org/cgi/content/abstract/140/3/496 http://www.ncbi.nlm.nih.gov/pubmed/20089773