A new meta-study analyzed 99 randomized, controlled trials to investigate the benefits of vitamin D for cardiometabolic health. The study found that an average supplemental dose of 3,320 IU of vitamin D per day was associated with reduced blood pressure, total cholesterol, hemoglobin A1C, and fasting blood insulin and glucose levels. This comprehensive review attempted to distill findings from sometimes inconsistent studies regarding the benefits of vitamin D supplementation.
The meta-study examined the details of the trials conducted worldwide and involving 17,656 participants. The researchers found that taking a median dose of 3,320 International Units (IU) of vitamin D per day was linked to significant cardiometabolic benefits, including reductions in blood pressure, cholesterol levels, hemoglobin A1C, and fasting blood glucose and insulin levels. The meta-study aimed to catalog differences between the trials to provide a more balanced understanding of the data and to compare the results in a fair manner.
The researchers discovered that vitamin D supplementation had the greatest impact on non-Western populations, individuals with lower levels of circulating vitamin D, those with a BMI under 30, and people aged 50 and older. The study highlighted heterogeneity in earlier studies, such as ethnocultural background, age, body weight, and initial vitamin D levels, as factors that contributed to conflicting findings regarding vitamin D supplementation and cardiometabolic risk factors.
According to Simin Liu, MD, ScD, the lead author of the meta-study, optimal levels of vitamin D for cardiometabolic health may vary based on a person’s ethnocultural background and biological characteristics. Individuals with obesity and low vitamin D levels may require higher doses of vitamin D for extended durations to achieve positive cardiometabolic health outcomes. The study also indicated that people with lower initial vitamin D levels experienced more significant improvements in cardiometabolic health when supplementing with vitamin D.
While the meta-study showed positive associations for 3,320 IU of vitamin D per day for many individuals, the researchers emphasized the importance of personalized intervention strategies based on individual factors. Jayne Morgan, MD, a cardiologist not involved in the study, noted the lack of direct cause-and-effect evidence linking vitamin D supplementation to cardiovascular health. However, she acknowledged the benefits of vitamin D on bone health, muscle function, and reduced inflammation, suggesting that positive effects on hypertension, diabetes, and lipids are worth further examination.
In conclusion, the meta-study provided valuable insights into the benefits of vitamin D supplementation for cardiometabolic health. While the findings point to potential advantages of taking a median dose of 3,320 IU of vitamin D per day, personalized intervention strategies based on ethnocultural background and biological features may be necessary to achieve optimal outcomes. Further research is needed to clarify the potential effects of vitamin D on cardiovascular health and to determine the most effective dosages for diverse populations.
