Vitamin D is a hormone and has many functions in the body:
- promotes the absorption of calcium, necessary for bone health
- supports immune response to infections
- helps to limit inflammation and regulate the immune system
Low Vitamin D is common and deficiency of Vitamin D (very low levels in the blood) may cause thin bones and increase the risk for fractures. Low Vitamin D may cause muscle weakness and a deficiency may increase your risk for certain types of cancer, heart disease and even mood disorders.
Several epidemiological studies (studies of populations) have shown that low Vitamin D is one of several risk factors
that can contribute to the development of MS. Other studies have suggested that low Vitamin D may be associated with more MS activity. However, it has not been established that correcting low Vitamin D impacts the MS disease course. Vitamin D and MS continues to be an active area of research.
Our best source of Vitamin D is sun exposure (about 15 minutes/day) – which allows our body to make its own Vitamin D by absorption through the skin. But with less time in the sun due to skin cancer risk, and the use of sunscreens, sun exposure is often limited. Also, for some, heat exposure can temporarily make MS symptoms feel worse. Food sources of Vitamin D include oily fish (such as salmon or tuna), beef liver, egg yolks, pork, fortified foods such as milk and juices. It is difficult to get sufficient Vitamin D from food, so most people who have low Vitamin D take a supplement.
It is possible to get too much Vitamin D from supplements, and too much can cause side effects – such as kidney stones, kidney failure, bone loss, fatigue, dizziness, confusion, vomiting and nausea. Your supplement dose needs to be individualized and ideally based upon your blood level of Vitamin D. Work with your MS provider or your primary care provider to determine the dose that you should take.