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Autoimmune disease
MS is a highly debilitating autoimmune disease characterised by demyelisation of the central nervous system. Recently, researchers have noticed that MS occurs more frequently in areas of the world with decreasing solar radiation or sunshine (Hayes, 2000). The prevalence of MS is thus highest in those regions where sunlight exposure and environmental vitamin D supplies are lowest (VanAmerongen et al, 2004).
We know that lack of exposure of the skin to sunshine is linked to low vitamin D levels, and studies have shown that MS patients tend to suffer from vitamin D deficiency (Hayes, 2000). Scientists have therefore come up with the suggestion that vitamin D may protect genetically susceptible individuals against MS.
Research studies
Research with experimental animals has indicated that the use of the active form of vitamin D – 1,25-(OH)(2)D – can prevent and reduce disease activity in mice and rats (VanAmerongen et al, 2004).
At present, no well-controlled studies have been carried out with vitamin D supplements in MS patients, but in view of the environmental evidence and the indication that vitamin D may be implicated in a variety of autoimmune diseases including MS, rheumatoid arthritis, insulin-dependent diabetes mellitus and inflammatory bowel disease (Cantorna & Mahon, 2004), vitamin D may well play an important role in MS.
How to make your own vitamin D
Exposing your skin to the sun for 30 minutes a day is sufficient to allow your body to make its own vitamin D. It's not necessary to expose the whole body. You only have to spend about half an hour going for a walk or sitting in the sun with your arms and legs exposed.
People with MS may not be able to sunbathe or want to lie on the beach, but they should be able to sit in a chair in the sun in the garden or on a balcony.
Self-production of vitamin D is still the best solution at this stage, as researchers cannot yet specify how much vitamin D we should ingest from our diet or from supplements.
Dietary sources of vitamin D
The best source of vitamin D is cod liver oil. But if you decide to take it as a supplement, keep in mind that it's easy to overdose on cod liver oil. Cod liver oil also contains very high levels of vitamin A, which can cause a condition called hypervitaminosis A. It's also possible to develop hypervitaminosis D if you take too much.
Hypervitaminosis A is characterised by bone pain, brittle bones, dry, cracked skin, brittle nails, hair loss, inflamed gums, anorexia, fatigue, liver damage and hypertension.
Hypervitaminosis D can cause negative symptoms such as excessive bone calcification, kidneys stones, excessive calcium levels in the blood, headaches, weakness, nausea, vomiting, constipation, excessive urination and excessive thirst. For safety’s sake it is, therefore, probably best to only take cod liver oil once or twice a week.
The following foods are also sources of vitamin D:
- Fresh herring
- Salmon
- Vitamin-D fortified milk
- Sardines
- Liver
- Shrimp
- Egg yolk
- Vitamin-D fortified margarine
People who have MS should make sure that they expose their skin to sunlight for 30 min a day and eat foods that are rich in vitamin D. Discuss the option of using a vitamin D supplement, including cod liver oil, with the doctor who is treating your MS and don’t overdose on vitamin D.
Until we know exactly what doses of vitamin D will help prevent and control MS or any other autoimmune disease, it's safer to sit in the sun for short periods and to eat vitamin D-containing foods than to take massive doses of this vitamin.
Smolders and coworkers (2008) have stated that “there is a sound basis on which to initiate double-blind placebo-controlled trails that not only address the effect of vitamin D on the clinical outcome of multiple sclerosis, but also on the regulatory T cell compartment.”
Hopefully, such research studies will pinpoint what doses of vitamin D are beneficial to MS patients and what levels of vitamin D supplementation are safe to use.
(Dr I V van Heerden, DietDoc, 9 February 2009)
References:
(Hayes CE (2000). Vitamin D: a natural inhibitor of MS. Proc Nutr Soc, 50(4):531-5; VanAmerogen BM et al (2004). MS & Vitamin D: an update. Eur J Clin Nutr, 58(8):1095-109; Cantorna MT, Mahon BD (2004). Mounting evidence of vitamin D as an environmental factor affecting autoimmune disease prevalence. Exp Biol Med, 229(11):1136-42.Smolders J et al, 2008. Vitamin D as an immune modulator in MS, a review. J Neuroimmunol, 194(1-2):7-17.)
