IMAGE DESCRIPTION: An image of Vitamin D capsules placed into a sun with Vitamin D writing. The ME Association logo (bottom right)

Vitamin D Overdose Information

Overdosing on vitamin D supplements is possible and harmful.

A case report in the BMJ:

The MEA Comments

Dr Charles Shepherd, Honorary Medical Adviser to the ME Association comments:

This is an important warning about the dangers of overdosing on vitamin supplements.

Although there have been some small research studies reporting minor abnormalities in vitamin status in ME/CFS, there is no firm evidence that vitamin deficiencies are present in people with ME/CFS, or that vitamin supplements are a safe and effective form of treatment for ME/CFS.

There are two exceptions::

Firstly, if someone with ME/CFS is taking a diet that may be restrictive in vitamin content then it would be sensible to take a good multivitamin supplement.

Secondly, we know from both patient evidence and research into vitamin D status in people with ME/CFS that there are some people, especially those at the severe end of the spectrum, who are deficient in vitamin D.

This is not surprising – because vitamin D is produced in the body through the action of sunlight on the skin and lack of exposure to the sun is a well recognised factor in producing vitamin D deficiency.

So, people with ME/CFS who are housebound, or largely housebound, and do not go outdoors, should check with their doctor about their vitamin D status – as any significant deficiency will need to be treated.

And, as the NHS now advises, everyone should consider taking a daily vitamin D supplement throughout the year. With a supplement, the daily requirement is 10 mcg or 400 IU. On a personal basis, I take a vitamin D supplement every day.

NHS guidance on vitamin D supplements can be found via the button below

The MEA information has a leaflet on Vitamin D deficiency and ME/CFS

Dr Charles Shepherd
Trustee and Honorary Medical Adviser
(Member of The NICE Guideline Committee on ME/CFS (2019 – 2021) and The DHSC Research Working Group (2022-23)

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