Taking vitamin D supplements has been shown in some studies to raise levels of irisin—a muscle-derived molecule linked to brain and muscle health—in people with type 2 diabetes.
Evidence from Studies
No evidence studies found yet.
What Would Prove This
Per GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this claim, ordered from strongest to weakest.
Whether vitamin D supplementation consistently increases irisin levels across diverse populations with type 2 diabetes and whether this effect is dose- and duration-dependent.
A systematic review and meta-analysis of at least 10 randomized controlled trials measuring serum irisin before and after vitamin D supplementation (dose range 1000–5000 IU/day) for 3–12 months in adults with type 2 diabetes, with pooled standardized mean differences and subgroup analysis by baseline vitamin D status, BMI, and age.
Whether vitamin D supplementation directly causes an increase in irisin and whether this increase is independent of changes in body composition or glycemic control.
A double-blind RCT of 100 adults with type 2 diabetes and baseline vitamin D deficiency (<20 ng/mL) randomized to 5000 IU/day vitamin D3 or placebo for 6 months, with serum irisin, HbA1c, fat mass (DXA), and muscle strength (leg press) measured at baseline and endpoint, controlling for physical activity.
Whether higher vitamin D intake or serum levels predict higher irisin levels over time in individuals with type 2 diabetes.
A prospective cohort study of 300 adults with type 2 diabetes followed for 2 years, with quarterly measurement of serum 25(OH)D, irisin, and physical activity, adjusting for dietary intake, BMI, and medication use.
The association between serum vitamin D levels and irisin concentrations in a population with type 2 diabetes.
A cross-sectional analysis of 250 adults with type 2 diabetes, measuring serum 25(OH)D and irisin levels, adjusting for age, sex, BMI, HbA1c, and season of blood draw.
Whether extreme changes in vitamin D status lead to dramatic irisin fluctuations in individuals with type 2 diabetes.
A case series of 5 individuals with type 2 diabetes and severe vitamin D deficiency (<10 ng/mL) who received high-dose vitamin D (50,000 IU/week for 8 weeks) and exhibited >40% increases in irisin alongside improved glycemic control.