Medical Matters > Treatment: Vitamin D & Safety

ME Essential Summer 2022


Following on from the question in the Summer issue of ME Essential about the risk of developing osteoporosis in ME and the use of vitamin D supplements, I was concerned to see a newspaper report about someone who had been recommended to take a vitamin D supplement by a nutritionist which had caused serious side-effects and resulted in hospital admission.

So should people with ME/CFS be taking vitamin D supplements? Or any vitamin supplement? And is it safe to do so?


There was an important warning about the dangers of overdosing on vitamin D in the British Medical Journal back in July. This is where the press reports came from. The person involved had been taking very high doses of vitamin D and this caused nausea and vomiting, abdominal pain, leg cramps and weight loss.

Although there have been some small 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

However, there are two important exceptions. Firstly, if someone with ME/CFS is taking a diet that may be restrictive in vitamin content 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.  The daily requirement is 10 micrograms or 400iu (international units). Inexpensive over the counter supplements containing this dose can be purchased from pharmacies.

See also: Treatment: Vitamin D

More information




Information provided by The ME Association should not be construed as medical advice. Don't assume any new or worsened symptoms are simply the result of having ME/CFS or Long Covid. We recommend that any information you deem relevant is discussed with your NHS GP as soon as possible. It is important that you seek personalised medical advice from the GP who is in charge of your care and who knows you well.

Search Medical Matters

Shopping Basket