Chronic dietary exposure to branched chain amino acids impairs glucose disposal in vegans but not in omnivores

• Published in: European journal of clinical nutrition Vol. 71; no. 5; pp. 594 - 601
• Main Authors: Gojda, J, Rossmeislová, L, Straková, R, Tůmová, J, Elkalaf, M, Jaček, M, Tůma, P, Potočková, J, Krauzová, E, Waldauf, P, Trnka, J, Štich, V, Anděl, M
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.05.2017; Nature Publishing Group
• Subjects: 631/443/319/1642/2037; 692/163/2743/2037; 82/29; Adipose tissue; Adipose tissues; Adult; Amino acids; Amino Acids, Branched-Chain - administration & dosage; Amino Acids, Branched-Chain - blood; Anthropometry; Biopsy; Blood Glucose - metabolism; Branched chain amino acids; Chain branching; Chains; Clinical Nutrition; Demographic aspects; Diet; Diet, Vegan; Dietary Exposure - adverse effects; Dietary Proteins - administration & dosage; Dose-Response Relationship, Drug; Electron transport; Epidemiology; Exercise; Female; Gene expression; Glucose; Glucose Clamp Technique; Glucose metabolism; Health aspects; Humans; Insulin; Insulin - blood; Insulin Resistance; Internal Medicine; Male; Medicine; Medicine & Public Health; Metabolic Diseases; mRNA; Muscle, Skeletal - drug effects; Muscle, Skeletal - metabolism; Muscles; Nutrients; Omnivores; original-article; Peroxisome proliferator-activated receptors; Physiological aspects; Prospective Studies; Public Health; Risk factors; Skeletal muscle; Surveys and Questionnaires; Veganism; Vegans; Vegetarianism; Vegetarians; Young Adult; Czech Republic
• ISSN: 0954-3007; 1476-5640; 1476-5640
• DOI: 10.1038/ejcn.2016.274

Background/Objectives: Branched chain amino acids (BCAA) are among nutrients strongly linked with insulin sensitivity (IS) measures. We investigated the effects of a chronic increase of BCAA intake on IS in two groups of healthy subjects differing in their basal consumption of BCAA, that is, vegans and omnivores. Subjects/Methods: Eight vegans and eight matched omnivores (five men and three women in each group) received 15 g (women) or 20 g (men) of BCAA daily for 3 months. Anthropometry, blood analyses, glucose clamp, arginine test, subcutaneous abdominal adipose tissue (AT) and skeletal muscle (SM) biopsies (mRNA levels of selected metabolic markers, respiratory chain (RC) activity) were performed at baseline, after the intervention and after a 6 month wash-out period. Results: Compared with omnivores, vegans had higher IS at baseline (GIR, glucose infusion rate: 9.6±2.4 vs 7.1±2.4 mg/kg/min, 95% CI for difference: 0.55 to 5.82) that declined after the intervention and returned to baseline values after the wash-out period (changes in GIR with 95% CI, 3–0 months: −1.64 [−2.5; −0.75] and 9-3 months: 1.65 [0.75; 2.54] mg/kg/min). No such change was observed in omnivores. In omnivores the intervention led to an increased expression of lipogenic genes (DGAT2, FASN, PPARγ, SCD1) in AT. SM RC activity increased in both groups. Conclusions: Negative impact of increased BCAA intake on IS was only detected in vegans, that is, subjects with low basal amino acids/BCAA intake, which appear to be unable to induce sufficient compensatory changes within AT and SM on a BCAA challenge.