It is reported that certain health conditions, including cardiovascular disease, type 2 diabetes, and cancer risk, have an increased prevalence in Black, Asian, and other minority ethnic groups. These groups may also be at increased risk of vitamin D deficiency and the below reasons may play a role. Combine these with the autumn and winter months when daylight hours are reduced and spending more time indoors due to adverse weather and lockdowns and risk of deficiency increases again.
Darker skin tone
Within Europe, dark-skinned ethnic groups have been shown to be at much increased risk of vitamin D deficiency compared to their white counterparts.1 Dark-skinned individuals will experience slower vitamin D synthesis than light-skinned ones as vitamin D synthesis is highly dependent on the concentration of melanin (skin pigment) in the skin2 – melanin lowers the skin's ability to make vitamin D in response to sunlight exposure. Melanin absorbs and scatters UVR-B, resulting in a less efficient conversion of 7- dehydrocholesterol to pre-vitamin D3.
Women who wear long robes and head coverings for religious reasons are unlikely to obtain adequate vitamin D from sunlight.3 Sunlight is required for ultraviolet-B (UVB)-induced vitamin D production in the skin.
A BMI value of ≥30 is associated with lower serum vitamin D levels compared with nonobese individuals. Obese people may need larger than usual intakes of vitamin D to achieve levels comparable to those of normal weight. Greater amounts of subcutaneous fat sequester (captivate) more of the vitamin and alter its release into the circulation.3 In addition to the aforementioned risk factors, it is reported that 73.6% of Black adults, 57.0% of Mixed ethnic and 56.5% Asian groups are overweight or obese meaning their risk of vitamin D deficiency is higher again.4 In the same government survey white British adults were more likely than average to be overweight or obese, but as their ability to produce vitamin D from sunlight is faster it is less likely to be a risk factor for vitamin D deficiency in this group.
The above groups are at risk of vitamin D deficiency all year round and should consider supplementing daily to keep levels topped up. However, the best way to evaluate supplement requirements is with a test. Your GP can check your vitamin D status, or alternatively there are many private companies offering vitamin D tests with a simple at-home finger-prick testing kit for around £30. If you do test, it is important that you work with a healthcare professional to evaluate your optimal daily dose. Ideally everyone should test twice yearly; at the end of summer and at the end of winter, to keep a close eye on any changes.
1. O Neill CM et al. A predictive model of serum 25-hydroxyvitamin D in UK white as well as black and Asian minority ethnic population groups for application in food fortification strategy development towards vitamin D deficiency prevention. J Steroid Biochem Mol Biol. 2017 Oct; 173: 245-252.
2. Bonilla C et al. Skin pigmentation, sun exposure and vitamin D levels in children of the Avon Longitudinal Study of Parents and Children. BMC Public Health. 2014; 14: 597..
3. Nair R & Maseeh A. Vitamin D: The “sunshine” vitamin. J Pharmacol Pharmacother. 2012 Apr-Jun; 3(2): 118–126.
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