Plasma amino acids, adiposity, and weight change after gastric bypass surgery: are amino acids associated with weight regain?

Purpose: Plasma concentrations of several amino acids (AAs) are positively correlated with obesity. The aim of this study was to examine if selected plasma AAs are associated with weight regain from 2 to 4 years after Roux-en-Y gastric bypass (RYGB).

Methods: In a prospective study with 165 patients, we examined the relationship between plasma aromatic AAs (AAAs), branched chain AAs (BCAAs), and total cysteine (tCys) 2 years after RYGB, with BMI at 2 years and with weight change from 2 to 4 years after surgery. Analyses were adjusted for relevant covariates.

Result: The investigated AAs at 2 years correlated positively with BMI at 2 years (P ≤ 0.003 for all). BCAAs and AAAs at 2 years correlated inversely with % weight loss from 0 to 2 years (P = 0.002 and P = 0.001, respectively), while the association was not significant for tCys (r = -0.14, P = 0.08). Plasma tCys at 2 years correlated positively with BMI at 4 years (P = 0.010) and with weight regain from 2 to 4 years (P = 0.015).

Conclusion: Plasma AAAs, BCAAs, and tCys at 2 years were associated with BMI at 2 years. In addition, plasma AAAs and BCAAs at 2 years were associated with weight loss from 0 to 2 years, while tCys at 2 years was associated with weight regain from 2 to 4 years after RYGB. These results suggest that high tCys at 2 years may be used as a prognostic marker for future weight regain. The study was registered in ClinicalTrials.gov (NCT0 1270451).