Vitamin D Supplementation Does Not Impact Insulin Resistance in Black and White Children.

Study answer

What this study found

Vitamin D3 supplementation did not improve fasting glucose, fasting insulin, or HOMA-IR over 12 weeks. Serum 25(OH)D increased in a dose-dependent manner, but vitamin D dose had no impact on insulin resistance outcomes. Across the cohort, 25(OH)D was inversely associated with insulin (r = -0.140, P = .017) and HOMA-IR (r = -0.146, P = .012) at baseline, yet this did not translate into a causal benefit from supplementation. Glucose, insulin, and HOMA-IR increased over time overall (F > 5.79, P < .003), but not in a way that favored vitamin D treatment.

Study & population

This was a multi-site, randomized, intent-to-treat dose-response trial in apparently healthy Black and White children in early puberty, ages 9 to 13 years.

Intervention

Oral vitamin D3 tablets were given once daily for 12 weeks at dose levels of 400 IU/day, 1000 IU/day, 2000 IU/day, or 4000 IU/day.

Key limitation

The intervention lasted only 12 weeks and enrolled generally healthy children with relatively sufficient baseline vitamin D status, which may have limited detectable benefit.

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Original abstract