Association of plasma concentrations of branched-chain amino acids with risk of colorectal adenoma in a large Japanese population

• Published in: Annals of oncology Vol. 28; no. 4; pp. 818 - 823
• Main Authors: Budhathoki, S., Iwasaki, M., Yamaji, T., Yamamoto, H., Kato, Y., Tsugane, S.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-04-2017
• Subjects: Adenoma - blood; Adult; Aged; Amino Acids, Branched-Chain - blood; Asian Continental Ancestry Group; branched-chain amino acid; colorectal adenoma; Colorectal Neoplasms - blood; Female; Humans; isoleucine; leucine; Male; Middle Aged; Odds Ratio; Risk Factors; valine; leucine; colorectal adenoma; branched-chain amino acid; valine; isoleucine
• ISSN: 0923-7534; 1569-8041
• DOI: 10.1093/annonc/mdw680

Available evidence from animal studies suggests that branched-chain amino acids (BCAAs) may have a protective effect against colorectal carcinogenesis. However, a possible effect of BCAAs against colorectal neoplasia has not been evaluated in humans. Here, we aimed to evaluate whether plasma concentrations of BCAA are associated with the risk of colorectal adenoma (CRA), a precursor lesion of colorectal cancer.
CRA cases and controls were identified from examinees who underwent total colonoscopy as part of a cancer screening program between 2004 and 2005 and responded to self-administered dietary and lifestyle questionnaires. We measured plasma concentrations of leucine, isoleucine and valine in 629 patients with adenoma and 584 controls. Unconditional logistic regression models were used to estimate odds ratio (OR) and 95% confidence interval (CI) for the association between BCAA and CRA risk after adjustment for potential confounders.
High plasma concentrations of leucine, valine and total BCAA were inversely associated with CRA risk after adjustment of potential confounders. The multivariate-adjusted ORs for the highest versus lowest quartiles were 0.60 (95% CI 0.42–0.87,Ptrend = 0.006) for leucine, 0.68 (95% CI 0.48–0.97,Ptrend = 0.09) for valine and 0.68 (95% CI 0.48–0.98,Ptrend = 0.10) for total BCAA. Further analysis by gender revealed that this inverse association was clearly evident in men, but not in women: the corresponding OR for leucine, valine and total BCAA was 0.50 (95% CI 0.32–0.80,Ptrend = 0.003), 0.60 (95% CI 0.38–0.95,Ptrend = 0.01) and 0.58 (95% CI 0.37–0.93,Ptrend = 0.04), respectively, in men and 0.78 (95% CI 0.42–1.45,Ptrend = 0.44), 0.77 (95% CI 0.41–1.43,Ptrend = 0.85) and 0.84 (95% CI 0.45–1.57,Ptrend = 0.81), respectively, in women.
Our finding suggests that BCAAs may have a beneficial influence against the process of colorectal carcinogenesis, at least in the early stage. The mechanisms underlying this potential association between BCAA and colorectal carcinogenesis warrant further investigation.