Vitamin D is often prescribed for bones in people with darker skin. The trials are thinner than you might think

Darker skin makes less vitamin D from sunlight, so people of South Asian, African and East Asian heritage are more often deficient, whether they live in India or abroad. Yet most trials of vitamin D and bones were done in white populations. A systematic review published in The American Journal of Clinical Nutrition on 30 September 2026, led from City St George's, University of London, is the first to focus only on non-white adults.

It found 12 randomised trials with 8,023 participants aged 18 to 90: Black Africans, South Asians, South Koreans and Chinese. Doses ranged from 400 to 6,400 IU a day, for 3 months to 5.3 years. Of 8 trials that measured bone mineral density, only one, in South Asians taking 400 IU a day for 12 months, found higher density at the hip than placebo. A marker of bone formation (bone-specific alkaline phosphatase) was higher with vitamin D when trials were pooled, but the result was no longer significant once one unusual trial, where both groups also took the bone drug risedronate, was left out. The single trial on fractures (5,106 people) found no difference.

The authors conclude that the evidence for vitamin D improving bone health in non-white adults remains limited. That is not the same as proof that it does nothing: the trials were few and varied widely. Correcting a measured deficiency is still standard care; the open question is whether extra vitamin D helps bones in people who are not deficient.