Vitamin B6, cardiovascular diseases, and diabetes mellitus

Vitamin B6 is a broad term for six water-soluble vitamins that can change forms. These include pyridoxal, pyridoxine, pyridoxamine, and their 5-phosphorylated forms, which are pyridoxal 5’-phosphate (PLP), pyridoxine 5’-phosphate, and pyridoxamine 5’-phosphate. PLP is the biologically active form of vitamin B6. It works as a coenzyme in many enzymatic processes that speed up the body’s most important metabolic reactions, including the synthesis, conversion and degradation of amines and amino acids, the supply of one-carbon units, transsulfuration, the synthesis of tetrapyrrole compounds and polyamines. PLP also has a big impact on the metabolism of homocysteine and the biosynthesis of different neurotransmitters. It inhibits the production of reactive oxygen species and advanced glycation end products, which are genotoxic compounds linked to aging and diabetes mellitus (DM), so it works as an antioxidant. In addition, PLP functions as a modulator of transcription factors, affects the activity of a number of enzymes, and can bind to steroid hormone receptors, playing a role in membrane transport. Researchers have reported that patients with type 2 DM and cardiovascular disease (CVD) exhibit lower levels of vitamin B6, whereas taking vitamin B6 supplements lowers the risk of diabetes and its vascular complications. We still don’t fully understand the mechanisms underlying the relationship between vitamin B6 and DM. Instead, a growing body of evidence suggests that vitamin B6 may protect against diabetes complications through its role as a scavenger of reactive oxygen species. Vitamin B6 deficiency has been linked to a number of clinically significant diseases, including autism, schizophrenia, Alzheimer’s disease, Parkinson’s disease, epilepsy, Down syndrome, DM, and cancer, although the underlying processes remain largely unclear. The purpose of this review was to discuss the role and specifics of the relationship between vitamin B6 and CVD and diabetes mellitus, as well as to analyze new trends and directions for future research. The analysis focused on the biological role of vitamin B6, tryptophan metabolism, and the correlation between vitamin B6, CVD, diabetes, and DNA damage in diabetes. The search was conducted in Scopus, Science Direct (from Elsevier) and PubMed, including MEDLINE databases. The keywords used were “vitamin B6”, “cardiovascular disease”, and “diabetes mellitus”. A manual search of the bibliography of publications was used to identify study results that could not be found during the online search.