Appy · 5 min
Vitamin D and South Asian bodies in the UK
3 sections · 5 min read
Why are South Asian people in the UK at higher risk of vitamin D deficiency?
Higher-risk groups include: people with darker skin tones; people who cover skin for religious or cultural reasons; people with limited outdoor time; and people who are overweight or obese (vitamin D is fat-soluble and sequestered in adipose tissue).
How does vitamin D deficiency affect fertility specifically?
Vitamin D acts more like a hormone than a typical vitamin. It influences over 2,000 genes and plays roles in cycle regulation, , endometrial receptivity, and egg maturation. In men it supports production and and morphology.
Two systematic reviews and meta-analyses (Chu et al 2018, Human Reproduction; Lv et al 2016, Archives of Gynecology and Obstetrics) found vitamin D sufficiency associated with improved live birth rates in women undergoing and . The evidence on whether supplementation in already-sufficient women improves outcomes is less clear, correcting deficiency is the higher-value target.
Quick check
Have you ever had your vitamin D measured?
What should you do if you think you're vitamin D deficient?
Safety note: vitamin D is fat-soluble and can accumulate to toxic levels. High-dose supplementation (above 4,000 IU daily) without blood monitoring is not recommended. Avoid branded high-dose protocols sold online without a test result, treat on evidence, not influencer advice.
For your doctor
I would value a serum 25-hydroxy vitamin D blood test. Risk profile (documented in my Appy summary): South Asian ethnicity, [skin coverage / limited outdoor time / BMI / autumn-winter sampling] as relevant. I would value the actual nmol/L result rather than only a 'normal/low' label, and a treatment and re-test plan if the level is below 50 nmol/L.
What this is for: getting the 25-OH test specifically, getting the number itself back, and having a re-test on the record so a low result is not just treated and forgotten. Standard primary-care request.
How did this land with you?
Read next
Reviewed by clinicians
Authored and reviewed by clinicians from the founding team. Information only, not personalised medical advice.