From InterAction 98, Spring 2018
Our medical advisor, Dr Gregor Purdie, answers a reader's question about the role of vitamin D in people with M.E.
I’ve been mostly bedbound with M.E. for the last 10 months. A friend of mine suggested that my symptoms might be being made worse due to lack of vitamin D. She said I should spend more time in the sun, but this is difficult when I’m confined to my bed most of the time. I’ve read that lack of vitamin D can contribute to pain, depression, fatigue and immune problems. I worry that this is compounding my M.E. and preventing me from getting better. Do you have any advice?
Dr Purdie says: There is a great overlap between the symptoms of M.E. and vitamin D deficiency, especially in people with M.E. who are housebound, and particularly those who are bedbound.
Vitamin D is an important fat-soluble vitamin required in the healthy metabolism of bones. The classic symptoms of Vitamin D deficiency are aching bones and muscles, poor sleep, tiredness and fatigue and gut problems. People with low vitamin D also seem to be prone to coughs and colds. These problems will very likely be familiar to people with M.E. Vitamin D deficiency can also cause weight gain, low mood and depression.
In today’s world we no longer see the classic rickets, and symptoms can come on insidiously. Although rare, older people with inadequate levels of vitamin D can suffer from osteomalacia, a form of thinning of the bones. From the GP perspective, guidance for GPs investigating low vitamin D levels is geared towards people with low calcium levels, osteoporosis, low-trauma fractures, those who have bowel problems that mean they cannot absorb vitamin D, severe anorexia nervosa, chronic liver disease and chronic kidney disease.
Vitamin D deficiency can certainly be compounded by the fact that we get 90% of our vitamin D from sunlight. In the British climate, it is recognised that there is not enough sunlight from October to March to allow our bodies to have sufficient vitamin D. Some authorities would advise supplementing through foods rich in vitamin D such as oily fish, red meat, mushrooms and foods fortified with vitamin D. An alternative would be vitamin D supplements of 10mcg per day from October to March, which you can buy over-the-counter.
When the weather becomes more clement, the sunlight usually helps restore vitamin D levels (and being exposed to sunshine should not adversely affect the condition of a person who has M.E.). Of course if you are bedbound, and particularly if you are sensitive to light, getting enough sun can be more of a challenge, and so you might consider taking vitamin D supplements all year round.
Although people with M.E. can have a higher risk of developing deficiency in vitamin D (frail and dark-skinned people are also at greater risk), the link between vitamin D and M.E. is an area where much more research is needed. We do not know whether there is just an overlap of symptoms between M.E. and low vitamin D levels, or how the two conditions interact. Therefore at present one cannot give a definitive answer to the question as to what the optimum dose would be for people with M.E., but over-the-counter supplements are safe and effective in the general population, and are a good starting point.
If taking supplements, do not exceed the recommended dose of supplements, as too much vitamin D can lead to too-high levels of calcium in the body.
In summary, people with M.E. should consider whether they are at risk of low vitamin D levels, particularly if they are housebound and particularly those who are bedbound. However, this remains an area where further research needs to be undertaken. At the moment the best solution is good dietary guidance, and safe over-the-counter supplements.