Vitamin D supplementation reduces insulin resistance in South Asian women living in New Zealand who are insulin resistant and vitamin D deficient – a randomised, placebo-controlled trial

Study answer

What this study found

Vitamin D supplementation improved insulin sensitivity in these insulin-resistant, vitamin D-deficient women, with benefit emerging once serum 25(OH)D reached about 80 nmol/L. In the vitamin D group, 25(OH)D rose from 21 (11, 40) nmol/L at baseline to 80 (67, 94) nmol/L at 6 months, with 93 (69, 103) nmol/L at 3 months. Insulin resistance improved (P = 0.02), insulin sensitivity improved (P = 0.003), and fasting insulin decreased (P = 0.02), while C-peptide did not change. No adverse effects were seen in serum calcium results at 3 months.

Study & population

Randomized, placebo-controlled trial in South Asian women living in Auckland, New Zealand.

Intervention

Vitamin D3 (cholecalciferol) 100 mg (4000 IU) daily, given as four 25 mg (1000 IU) capsules per day for 6 months.

Key limitation

The active intervention arm was small and restricted to South Asian women, limiting generalizability.

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Original abstract