This review provides a comprehensive analysis of the role of vitamin D in health, particularly focusing on older adults. Vitamin D is well-known for preventing and curing nutritional rickets in infants and children and is essential for bone health in older adults, with guidelines recommending serum 25-hydroxyvitamin D (25OHD) concentrations above 50 nmol/l. However, the causal relationship between vitamin D and various extra-skeletal outcomes, such as prevention of cancer, cardiovascular events, falls, or progression to type 2 diabetes, remains uncertain.
Large-scale randomized clinical trials like VITAL, ViDA, and D2d, involving over 30,000 participants, indicated that vitamin D supplementation in individuals with adequate vitamin D levels does not prevent these conditions. Additionally, over 60 Mendelian randomization studies aimed at reducing bias found mostly null effects of genetically lowered serum 25OHD concentrations on various health outcomes, although some studies did suggest an increased risk of multiple sclerosis with lower vitamin D levels. In summary, while the supplementation of vitamin D in individuals with adequate levels does not demonstrate broad health benefits, the correction of severe vitamin D deficiency remains essential for health maintenance.
Original Publication:
Bouillon, R., Manousaki, D., Rosen, C., Trajanoska, K., Rivadeneira, F., & Richards, J. B. (2022). The health effects of vitamin D supplementation: evidence from human studies. Nature Reviews Endocrinology, 18(2), 96-110.
https://doi.org/10.1038/s41574-021-00593-z
