Abstract
Background and Objectives: Among nutritional factors implicated in periodontal health, the vitamin B complex-particularly folate (vitamin B9), cobalamin (B12), thiamine (B1), and riboflavin (B2)-has gained attention for its role in immunomodulation and tissue repair. This systematic review aims to synthesize current evidence on whether adequate vitamin B complex intake or status is associated with improved periodontal outcomes. Methods: A systematic search was performed in PubMed, Scopus, and Web of Science for observational studies investigating vitamin B complex intake or status in relation to periodontal disease indicators. Articles were screened according to PRISMA guidelines, and five studies met inclusion criteria. Results: Five observational studies were included. In older adults, each standard deviation increase in serum folate was associated with an approximate 26% reduction in periodontal disease odds ratio (OR = 0.74, 95% confidence interval (CI) 0.58-0.93). Among young adult women, inadequate riboflavin (B2) and pyridoxine (B6) intake correlated with higher community periodontal index (CPI) scores (p < 0.05). In a large NHANES-based cohort, insufficient thiamine (B1) intake yielded a 33% higher likelihood of severe periodontitis (p < 0.05), while adequate riboflavin was protective (OR = 0.90). Another dose-response analysis (n = 8959) indicated up to a 30% risk reduction for moderate folate or B1 intake, but no extra benefit with excessive intake. Finally, a UK Biobank analysis (n = 9476) showed that those in the highest quartile of a "high micronutrient" dietary pattern-including vitamins B6 and folate-had a 24% lower risk of self-reported periodontal disease (OR = 0.76, 95% CI 0.65-0.90) compared to the lowest quartile. Conclusions: Across diverse populations, inadequate vitamin B complex intake-especially folate-was consistently linked to worse periodontal outcomes.