The lowdown: Vitamin D

Vitamin D

Vitamin D is essential to bone health and helping the immune system function. It is made in our skin when we’re exposed to sunlight and as we’re approaching the summer months, I thought it would be the perfect time to post this.

In the winter months, October to April, it is recommended that everyone in the UK takes a daily vitamin D supplement with at least 10µg or 400 IU vitamin D in it. There are some high risk groups that may benefit from year round supplementation to avoid deficiency:

• -          Elderly
• -          People who have a lot their skin covered e.g. some religious groups
• -          People who spend a lot of time indoors
• -          People with darker complexions

This is because they are less likely to get the sun exposure needed to make enough vitamin D.

During summer we should be able to get enough sun exposure to make all the vitamin D we need, but this is where it gets a bit unclear as repeated sun exposure can increase the risk of skin cancer. The sun is strongest from 11am-3pm and sunscreen should be worn if you're outside.

Recent research shows that wearing sunscreen doesn’t affect vitamin D status in healthy individuals. Wearing an SPF of 15 doesn’t impact vitamin D production and can protect your skin on a moderate day. More research is needed, but other studies suggest that you can wear up to SPF 30 and still produce sufficient vitamin D. Overall, the protection that sunscreen gives is vital to help prevent skin cancer and it is unlikely to lead to vitamin D deficiency in healthy individuals.

Vitamin D is also found in some foods like egg yolks, fortified breakfast cereals, oily fish like tuna or salmon, and some butters or margarines. But it is not in a high enough quantity to provide our daily needs so sun exposure or a supplement is needed.

Take home messages:

• -          Vitamin D is essential for bone health and the immune system
• -          Vitamin D is made in our skin when exposed to sunlight
• -          When out in the sun wear sunscreen as your skin can still make vitamin D
• -          In the winter (or year round if high risk), supplement with at least 10µg/400IU vitamin D

I hope you found this post helpful.

Bye for now! 👋

References:

Dietary Reference Values: a guide. Pages 32 – 33. https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/743790/Dietary_Reference_Values_-_A_Guide__1991_.pdf

Vitamin D and the Immune system https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3166406/

Food sources of vitamin D https://www.cambridge.org/core/journals/proceedings-of-the-nutrition-society/article/vitamin-d-deficiency-as-a-public-health-issue-using-vitamin-d2-or-vitamin-d3-in-future-fortification-strategies/49816B8345AFC98DB16320F12608E2A2 and https://www.ncbi.nlm.nih.gov/pubmed/27777183

Sunscreen and vitamin D: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6899926/ and https://www.ncbi.nlm.nih.gov/pubmed/30945275