Vitamin B6 intake and health effects:associations with chronic diseases and adverse effects of long-term highdose intake
10.4163/jnh.2026.59.2.192
- Author:
Min Young UM
1
;
Kyung Hee HONG
;
Eun Young CHOI
Author Information
1. Food Functionality Research Division, Korea Food Research Institute, Wanju 55365, Republic of Korea
- Publication Type:Review
- From:Journal of Nutrition and Health
2026;59(2):192-201
- CountryRepublic of Korea
- Language:English
-
Abstract:
Vitamin B6 is an essential water-soluble vitamin involved in amino acid metabolism, neurotransmitter synthesis, heme biosynthesis, and one-carbon metabolism. Its active form, pyridoxal-5′-phosphate (PLP), serves as a coenzyme in more than 100 enzymatic reactions and is critical for maintaining metabolic homeostasis, immune regulation, and nervous system function. Epidemiological studies have reported inverse associations between vitamin B6 intake or the circulating PLP concentrations and the risk of cardiovascular disease, certain cancers, and diabetes-related metabolic dysfunction. The proposed mechanisms include the modulation of inflammation, oxidative stress, and homocysteine metabolism. Nevertheless, most available evidence is derived from observational studies conducted in Western or non-Korean populations, limiting generalizability and precluding revisions to current intake recommendations based on the chronic disease outcomes. Relevant epidemiological studies, mechanistic evidence, and recent international and national risk assessment reports were reviewed. Although excessive intake from habitual diets is uncommon, the increasing use of dietary supplements has raised concerns regarding chronic high-dose exposure. Accumulating human evidence suggests that long-term supplementation with high pyridoxine doses may induce sensory peripheral neuropathy, even at lower intake levels than previously assumed. Accordingly, recent international risk assessments, including the 2023 re-evaluation by the European Food Safety Authority, have proposed substantially lower Tolerable Upper Intake Level (UL) using benchmark dose modeling based on human data. In the 2025 Dietary Reference Intakes for Koreans, the UL for adults was set at 50 mg/day, reflecting the updated safety evidence and domestic supplement use patterns, while the recommended intake levels were maintained based on the established metabolic requirements. Further population-specific prospective studies and long-term safety data are needed to refine intake guidance and strengthen evidence-based risk management strategies in Korea.
