Branched-chain amino acids as a novel biomarker of metabolic disturbances in women with polycystic ovary syndrome — literature review

Polycystic ovary syndrome (PCOS) is a common, heterogeneous endocrine disorder which effects 5–10% of reproductive-age women. Recently, an association between PCOS and an increased risk of developing metabolic disturbances, such as insulin resistance, prediabetes, type 2 diabetes mellitus as well as obesity has been emphasised. Branched-chain amino acids (BCAAs), including valine (Val), leucine (Leu) and isoleucine (Ile), are a group of essential amino acids that cannot be synthesized in human body and need to be obtained from food. Several recent studies provide evidence that plasma BCAAs also serve as crucial nutrient signals and metabolic regulators. Interestingly, latest metabolomics analysis shows abnormalities in amino acid catabolism and biosynthesis in patients with PCOS, particularly in BCAAs. A growing body of evidence proves that elevated levels of BCAAs may have adverse effects on metabolic health leading to the development of insulin resistance, prediabetes, type 2 diabetes mellitus and obesity both in human and animal models. The aim of this review is to assess the current state of knowledge about the potential role of BCAAs as a novel biomarker of metabolic disturbances in women with polycystic ovary syndrome based on recent scientific literature published up to July 2021 and searches of the PubMed, Google Scholar, and Web of Science databases.