Researchers announced that a seven-year study of multiple sclerosis (MS) in England found highest rates of the disease among Britons who got the least sun and who also had a history of infection with the "kissing disease," mononucleosis.
Lack of Vitamin D Increases the Risk of Infections that Cause the Immune System to Misfire
Researchers have long known that multiple sclerosis is more common in northerly latitudes where summer sunshine is weaker and winter sunshine can be nearly nonexistent. The obvious interpretation of the 176 studies confirming this effect is that somehow vitamin D deficiencies cause the disease. Seven studies also confirmed that consumption of fish oils, which are naturally high in vitamin D, reduce the risk of the disease, but researchers had assumed that the protective effect of fish oils was due to anti-inflammatory omega-3 essential fatty acids rather than the vitamin.
Mononucleosis is caused by an infection with the Epstein-Barr Virus, also known as EBV. Previous studies have failed to find EBV in the spinal fluid or brains of people who have MS, so some researchers are skeptical of the current findings. For example, Dr. Donald Gilden, multiple sclerosis researcher at the University of Colorado, told Reuter's Health that he does not believe that the Epstein-Barr Virus has any role in the development of the disease.
Another reason to question the findings of the study is the observation that the overwhelming majority of people who get kissing fever never develop multiple sclerosis, and neither do most people who shun the sun. Any link between sunlight, vitamin D deficiency, Epstein-Barr Virus, and multiple sclerosis must involve other, additional factors.
The current study does, however, raise the possibility that vitamin D supplementation might help prevent multiple sclerosis. A study at the Harvard School of Public Health failed to find that vitamin D supplements slowed the progression of multiple sclerosis, but no prospective studies involving large numbers of people taking vitamin D supplements over a period of years have yet been completed.
The best evidence for the use of vitamin D supplements by people who have already been diagnosed with multiple sclerosis is the Swank Diet, which allows eating white fish (water-packed tuna, sturgeon, sole, snapper, smelt, perch, mai-mai, haddock, flounder, and cod) in unlimited quantities and eating salmon up to once a day. The Swank diet also encourages MS patients to take up to 5 grams of cod liver oil, which would provide as much as 20,000 IU of vitamin D daily.
Used by tens of thousands of people who have MS since the 1940's, the Swank Diet seems to reduce relapses and to prolong remissions, but the protocol is too complicated to be studied with scientific precision. For the time being, the best option for people who have already been diagnosed with MS is to follow an anti-inflammatory diet with cod liver oil as the source of vitamin D, and to continue any medical treatments that the doctor believes are working.