Possible Causes of Multiple Sclerosis
Researchers have studied a variety of possible causes for multiple sclerosis (MS), and a combination of factors appears to be involved. A popular theory looks at commonly known slow-acting viruses (one that could remain dormant for many years), such as measles, herpes, human T-cell lymphoma, and Epstein-Barr. After being exposed to one of these viruses, some researchers theorize that MS may develop in genetically susceptible people.
In the absence of a solid understanding of the mechanisms that underlie MS, no compelling candidate genes for MS have been identified. For this reason, the list of genes that have been investigated for MS susceptibility is long and continually expanding. Genes have some role in susceptibility to MS, but the exact mechanisms remain unclear. Nevertheless, genetic studies in MS have clearly shown that the increased frequency of MS seen within families is a result of relatives sharing DNA (the molecule that carries our genetic information) and not from living together as a family in the same environment.
Some scientists are looking for a connection between MS and nutritional factors, including fat intake, as well as deficiencies in fish oil and vitamin D. The idea that a diet rich in saturated fat may increase one’s risk of getting MS, as well as worsen his or her disease course, has been a popular theory for several decades.
Both Dr. Roy Swank and Dr. John McDougall have promoted diets with very low saturated fats for individuals with MS. Individuals with MS on the Swank Diet were followed for almost 50 years, and benefits such as fewer symptoms, greater mobility, and greater longevity were reported. However, incomplete follow-up and the lack of a control group to compare results prevent these claims from being considered as evidence-based medicine. Scientific clinical trials need to be conducted before any conclusions can be made. However, a nutritious diet – such as a heart-healthy diet – can control weight, blood sugar, and blood pressure, and is generally recommended.
In addition to food and supplements, vitamin D is also derived from sunlight, which may be involved in the development of MS. As noted in the section, Who Gets MS, populations living closer to the equator experience a lower incidence of MS. A popular theory is that those living closer to the equator are exposed to more sunlight and therefore are less likely to experience a vitamin D deficiency (studies suggest that low levels of vitamin D may increase one’s risk of MS).
Also noted in the section, Who Gets MS, parasites are another possible risk factor in the development of MS. Research has found that parasites can modulate the immune system and dampen its responses. People who have parasites are less likely to be diagnosed with MS, and as conditions in different countries become cleaner – with fewer parasites – the number of individuals being diagnosed is increasing in these parts of the world.
Another factor linked to MS is cigarette smoking. Women who smoke are 1.6 times more likely to develop MS than women who are non-smokers. Individuals with MS who smoke also appear to be at a much greater risk of experiencing a more rapid progression of their disease.
Other potential causes continue to be investigated, some of which show promise, while others create much controversy within the MS community. Receiving a great amount of attention during recent years is the possible connection between chronic cerebrospinal venous insufficiency (CCSVI) and MS. CCSVI is a complex condition involving changes in blood flow from the brain back to the heart, which some researchers theorize could possibly lead to activation of the immune system, excess iron deposits, loss of myelin, and other nervous system damage.
While this theory has a large following, CCSVI also has a great amount of opposition. Despite the controversy, some patients have opted for risky treatments on their own, sometimes going to clinics outside of the country. A recent, large study in Italy did not support the link of CCSVI and MS. Numerous other CCSVI research projects are still in progress, including research in Europe and the United States. In May 2012, the United States Food and Drug Administration (FDA) issued a warning about experimental therapies aimed at treating chronic cerebrospinal venous insufficiency (CCSVI), informing healthcare professionals and patients about the resulting injuries and deaths that have occurred.
As with any unproven theory and treatment, interested patients are strongly encouraged to first talk with their doctor. If appropriate, individuals may seek to participate in an approved clinical trial. Without a tested and proven protocol for the diagnosis and treatment of CCSVI, individuals could be putting themselves at risk by undergoing a procedure in a non-research, “commercial” setting. Caution and skepticism is advised pertaining to research projects that have not been reviewed by the FDA, are not listed on clinicaltrials.gov, and charge “retail prices” or require travel to a foreign country for the procedure.