Abstract P150: Weight-Loss Diets and 2-Year Change of Circulating Amino Acids in Two Randomized Intervention Trials

Abstract

Background: Emerging evidence has related circulating amino acids to diabetes and cardiovascular risk. Little is known about how diet modifications affect circulating amino acids. The present study aimed to examine the effects of weight-loss diets on long-term changes in plasma amino acids, and their relations with weight loss and metabolic outcomes. Methods and Results: We repeatedly measured plasma amino acid profiles over 2 years among overweight or obese participants from two randomized dietary interventional weight-loss trials: 774 from the Preventing Overweight Using Novel Dietary Strategies trial (POUNDS LOST) and 318 from Dietary Intervention Randomized Controlled Trial (DIRECT). The plasma levels of most amino acids decreased from baseline during follow-up in both trials. In the POUNDS LOST trial, compared to the high-protein diets, the average-protein weight-loss diets showed a greater effect on decreasing plasma levels of a diabetes-associated branched-chain amino acid (BCAA) valine and another amino acid methyl-histidine at 6 months, independent of weight change (p<0.002). Furthermore, the changes of plasma BCAA leucine/isoleucine, aromatic amino acid tyrosine and phenylalanine, and four other amino acids (alanine, sarcosine, hydroxyproline, and methionine) were positively related to concurrent weight loss, consistently in both trials (5-13g weight loss per 1 unit decease in log[amino acid in μmol/L], p<0.002). Moreover, the changes in tyrosine and alanine were positively related to changes in insulin resistance, independent of weight change, in both trials (p<0.05). Conclusion: Our findings underscore the potential importance of weight-loss dietary interventions in improvement of amino acid profiles and related cardiometabolic risk.