A new study from researchers in New Zealand has found that vitamin D supplements may improve insulin resistance and sensitivity, both of which are significant risk factors for type 2 diabetes.
The new study was a randomised, controlled, double-blind trial involving 81 South Asian women aged between 23 and 68 with insulin resistance. The women were randomly assigned to receive either 100 micrograms (4,000 IU) of vitamin D3 or placebo daily for six months.
The results were published recently in the British Journal of Nutrition; scientists found that insulin resistance was significantly lower in the women taking high-dose vitamin D supplementation. The researchers commented that at the end of the test period, women in the vitamin D group experienced “significant improvements” in both insulin sensitivity and resistance, which was accompanied by a decrease in fasting insulin levels, compared to placebo.
Researchers noted the biggest improvement in insulin resistance when blood levels of vitamin D, measured as 25-hydroxyvitamin D (25 (OH) D) – the non-active storage form of the vitamin were at least 80 nanomoles per litre.
The researchers commented, “improving vitamin D status in insulin resistant women resulted in improved IR and sensitivity, but no change in insulin secretion. Optimal vitamin D concentrations for reducing IR were shown to be 80 – 119 nmol / l, providing further evidence for an increase in the recommended adequate levels”.
Source:
British Journal of Nutrition
Published online ahead of print, doi: 10.1017/S0007114509992017
Von Hurst, Stonehouse & Coad “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”
