A novel dietary intervention reduces circulatory branched-chain amino acids by 50%: A pilot study of relevance for obesity and diabetes

Ramzan, Imran; Taylor, Moira; Phillips, Beth; Wilkinson, Daniel; Smith, Kenneth; Hession, Kate; Idris, Iskandar; Atherton, Philip

Abstract

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. Elevated circulating branched-chain amino acids (BCAAs; isoleucine, leucine, and valine) are associated with obesity and type 2 diabetes (T2D). Reducing circulatory BCAAs by dietary restriction was suggested to mitigate these risks in rodent models, but this is a challenging paradigm to deliver in humans. We aimed to design and assess the feasibility of a diet aimed at reducing circulating BCAA concentrations in humans, while maintaining energy balance and overall en-ergy/protein intake. Twelve healthy individuals were assigned to either a 7-day BCAA-restricted diet or a 7-day control diet. Diets were iso-nitrogenous and iso-caloric, with only BCAA levels differing between the two. The BCAA-restricted diet significantly reduced circulating BCAA concentrations by ~50% i.e., baseline 437 ± 60 to 217 ± 40 µmol/L (p < 0.005). Individually, both valine (245 ± 33 to 105 ± 23 µmol/L; p < 0.0001), and leucine (130 ± 20 to 75 ± 13 µmol/L; p < 0.05), decreased significantly in response to the BCAA-restricted diet. The BCAA-restricted diet marginally lowered Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) levels: baseline 1.5 ± 0.2 to 1.0 ± 0.1; (p = 0.096). We successfully lowered circulating BCAAs by 50% while maintaining iso-nitrogenous, iso-caloric dietary intakes, and while meeting the recommended daily allowances (RDA) for protein requirements. The present pilot study represents a novel dietary means by which to reduce BCAA, and as such, provides a blueprint for a potential dietary therapeutic in obesity/diabetes.

Citation

Ramzan, I., Taylor, M., Phillips, B., Wilkinson, D., Smith, K., Hession, K., Idris, I., & Atherton, P. (2021). A novel dietary intervention reduces circulatory branched-chain amino acids by 50%: A pilot study of relevance for obesity and diabetes. Nutrients, 13(1), Article 95. https://doi.org/10.3390/nu13010095

• Journal Article Type: Article
• Acceptance Date: Dec 25, 2020
• Online Publication Date: Dec 30, 2020
• Publication Date: Jan 1, 2021
• Deposit Date: Jan 5, 2021
• Publicly Available Date: Jan 5, 2021
• Journal: Nutrients
• Electronic ISSN: 2072-6643
• Publisher: MDPI
• Peer Reviewed: Peer Reviewed
• Volume: 13
• Issue: 1
• Article Number: 95
• DOI: https://doi.org/10.3390/nu13010095
• Keywords: Food Science
• Public URL: https://nottingham-repository.worktribe.com/output/5184307
• Publisher URL: https://www.mdpi.com/2072-6643/13/1/95/htm