Are BCAAs Mere Biomarkers of Diabetes?
Branched-chain amino acids are essential amino acids we need to ingest through our diet.
While circulating BCAA levels were first found to be elevated in obese individuals
back in 1969 by Felig and colleagues, the potential role of BCAAs in obesity and diabetes
development has been re-highlighted in the last decade.
Using advanced metabolomic platforms, many independent investigators were able to reproduce
the earlier finding and further demonstrate that not only plasma BCAAs,
but also their partially oxidized intermediates such as α-keto acids and short-chain acylcarnitines are
increased in obese or insulin resistant/diabetic individuals, including Caucasians and Asians.
Moreover, plasma BCAAs are found to be the earliest and the most predictive marker for future
risk of diabetes, and elevated plasma leucine levels precede the development of fatty liver,11
suggesting that circulating leucine is a predictive marker of hepatic steatosis. Interestingly,
plasma BCAAs and their derived short-chain acylcarnitines are effectively lowered by bariatric
surgery in obese and/or diabetic individuals.
Whether this normalized BCAA metabolism after RYGB surgery in morbidly obese patients
contributes to improved insulin sensitivity and glycemic control or is just a secondary
effect of the surgery needs to be examined further.
Nonetheless, collectively these studies implicate a role of plasma BCAAs and their metabolites
in the pathogenesis of insulin resistance and diabetes.
The unresolved question in the field today is whether or not they are mere biomarkers or they are one of the potential culprits for derangement of glucose metabolism and development of obesity and insulin resistance/diabetes.
Diabetes Res Open J. 2017; 3(1): e4-e8. doi: 10.17140/DROJ-3-e009
