Sex-Specific Correlation Analysis of Branched-Chain Amino Acids in Dietary Intakes and Plasma among Chinese Adults

Background: Previous findings about the influence of dietary intakes of the branched-chain amino acid (BCAA) on their plasma concen-trations have been limited and inconsistent, and evidence from the Chinese population was lacking. Objectives: This study aimed to investigate the diet-plasma BCAA correlations in Chinese male and female adults. Methods: This cross-sectional study was based on a nested case-control study within 2 prospective population-based cohorts in Shanghai, China. Diet information was collected by the food frequency questionnaires. Plasma BCAA concentrations were measured by ultra -performance liquid chromatography coupled with tandem mass spectrometry. Spearman correlations and linear regression models were conducted to examine the relationships between dietary BCAA intakes and plasma BCAA. The multivariable model was adjusted for age at the interview, total energy intake, time of blood collection from last meal, dietary patterns, body mass index (in kg/m2), type 2 diabetes, and physical activity. Results: A total of 322 males (median age of 57.0 y) and 187 females (median age of 60.0 y) were included in this cross-sectional study. The geometric means of dietary intake of leucine, isoleucine, valine, and BCAA were 4937.7, 3029.6, 3268.5, and 11237.4 mg/d in males, and 4125.7, 2567.8, 2754.3, and 9449.4 mg/d in females. The geometric means of plasma concentrations of leucine, isoleucine, valine, and BCAA were 181.9, 65.0, 219.8, and 469.4 mu M/L in males and 161.6, 61.1, 206.5, and 431.6 mu M/L in females. Only leucine (r = 0.1660, P = 0.0028) and total BCAA (r = 0.1348, P = 0.0155) in males exhibited weak positive correlation coefficients. After adjustment for the covariates, leucine, isoleucine, valine, and total BCAA in dietary intakes and plasma were not correlated in both males and females. Conclusions: In Chinese male and female adults, dietary intakes are not major determinants of plasma concentrations of BCAA, and plasma concentrations might not be reflected by usual dietary intakes of BCAA.