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Do vitamin D requirements vary between ethnicities?

Posted on: August 6, 2018   by  Vitamin D Council


Vitamin D supplementation is imperative for most people to maintain healthy vitamin D levels. However, current recommendations do not differentiate between ethnic groups. Melanin competes with with the vitamin D in our skin for UVB absorption. As a result, those with more melanin in their skin produce less vitamin D through sun exposure than during a given period of time than those with a lighter skin type. Therefore, researchers theorize vitamin D supplement requirements may differ between skin types.

African American and dark-skinned ethnic subgroups are at an increased risk of vitamin D deficiency than caucasians. In fact, it is estimated that vitamin D deficiency is over 20% more prevalent among African Americans compared to Caucasians. It has been also shown that populations in northern latitudes have a higher prevalence of vitamin D deficiency.

The study

In a new study, researchers evaluated data from a recent randomized controlled trial. The trial studied 125 women of Somali (East African) and Caucasian (Finnish) ethnicities, and serum 25(OH)D response to vitamin D supplementation was the main outcome assessed. For baseline measurements, both groups of women were randomized into three supplementation groups, either placebo, 400 or 800 IU vitamin D3 per day.

The results

  • At baseline the, Somali group were older (by 12 years; p < 0.001), had a greater BMI (by 2 kg/m2; p < 0.001) and a greater body weight (by 12.5 kg; p < 0.001).
  • Average vitamin D levels were 3.32 ng/ml lower among Somali women compared to Caucasian women (p = 0.006).
  • Somali women required a 1.3 – 1.5 times higher dose compared to Caucasian women to maintain vitamin D levels greater than 20 ng/ml (50 nmol/l).
  • They found that 8 mcg/day (320 IU) vitamin D intake was necessary for Caucasian women to maintain serum 25(OH)D levels > 12 ng/ml (30 nmol/L), whereas 18 mcg/day (720 IU) vitamin D was necessary for the Somali women to maintain level > 12 ng/ml (30 nmol/L).

This study demonstrates the different vitamin D requirements for different ethnicities. More research is required to better understand dose-response vitamin D interventions for specific ethnicities.


Cahsman, K et al. Differences in the dietary requirements for vitamin D among Caucasian and East African Women at northern latitude. European journal of nutrition. 2018

1 Response to Do vitamin D requirements vary between ethnicities?

  1. Ron Carmichael

    So sad to see the opportunity for greater effectiveness of a study lost/squandered because of inadequate, nay, pharmacologically-insignificant doses of D3. One is forced to only imagine what the outcome would have been had they administered 5,000 or 10,000iu of D3 instead of 320iu or 720iu.

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