In a recent study published in Diabetologia, levels of tyrosine and other amino acids were more strongly linked to risk for diabetes in South Asian men as compared with white European men.
“South Asian individuals have an increased risk of diabetes compared with Europeans that is unexplained by obesity and traditional or established metabolic measures. Circulating amino acids (AAs) may provide additional explanatory insights,” study researcher Therese Tillin, of the UCL Institute of Cardiovascular Science at University College London in the United Kingdom, and colleagues wrote.
For the study, the researchers compared cross-sectional associations between amino acids, metabolic and obesity traits, and associations with the development of diabetes over 20 years. They used nuclear magnetic spectroscopy to measure baseline levels of nine amino acids in serum samples.
The London population-based cohort included 1,279 white European and 1,007 South Asian men without diabetes, aged 40 to 69 years, from the Southall and Brent Revisited (SABRE) cohort. Complete 19-year follow-up was available for 801 European and 643 South Asian participants.
The researchers reported that diabetes developed in 227 South Asian men (35%) and 113 European men (14%), with data indicating stronger adverse associations between branched chain and aromatic amino acids and diabetes in South Asian men.
Results also revealed significantly higher concentrations of isoleucine, phenylalanine, tyrosine and alanine in South Asian men. Cross-sectional correlations of amino acids with glycemia and insulin resistance were comparable in the two ethnic groups, but most amino acids were less strongly associated with measures of obesity in South Asian men.
“The latter findings, together with the weaker attenuation of [amino acid] associations with incident diabetes, suggest that conventional measures may not capture the best indicators of diabetes risk in South Asian individuals,” the researchers wrote.
Tyrosine in particular was a strong predictor of incident diabetes in this population. Even after adjustment for metabolic risk factors like obesity and insulin resistance, one standard deviation increase in tyrosine increased diabetes risk by 10% in European men (P=.4) vs. 47% in South Asian men (P=.001).
The researchers found a similar pattern for some other amino acids, including phenylalanine, isoleucine, leucine and valine.
Overall, the researchers concluded: “These findings suggest that higher branched chain and aromatic [amino acids], particularly tyrosine, may be a focus for identifying novel etiological mechanisms and potential treatment targets for diabetes in South Asian individuals and may contribute to their excess risk of diabetes.”