The incidence of autoimmune disorders, such as multiple sclerosis (MS), rheumatoid arthritis (RA), inflammatory bowel disease (IBD), systemic lupus erythematosus (SLE), type 1 diabetes mellitus, and others are increasing globally. But just what is an autoimmune disorder and what part do environmental factors play in their development? Let’s get a closer look.
In people who have an autoimmune disorder, their immune system becomes overactive and produces antibodies that instead of fighting bacterial or viral invaders, actually attack the body’s own tissues. These autoimmune diseases are serious and cause much suffering and disability for those who are afflicted with them.
While the factors that trigger an autoimmune disorder in a particular person may be unknown, scientific evidence is increasingly pointing toward environmental factors as being a major player in the development of autoimmune disorders. Although there is recognition that genetics may play a part, it’s now understood that genetics only count for a small portion of autoimmune disorders. However, underlying genetic susceptibility, together with the right environmental trigger, can be enough to bring on the onset of an autoimmune disorder.
So, what do we mean by “environmental” triggers? These environmental triggers include infection, climate, occupation, cigarette smoking, and stress. But one of the most interesting environmental triggers that is getting a lot of attention is diet. Most people don’t think of diet as an environmental factor, but your diet directly exposes every cell in your body, through your gastrointestinal tract and subsequent absorption into your bloodstream, to all the nutrients and chemicals that you ingest.
Among the reasons that scientists are looking at diet as a trigger for autoimmune diseases is that the nearly global adoption of “Westernized” food, with its high levels of fat, salt, sugar, and protein intake, has already been associated with the development of diseases such as cardiovascular conditions and cancer. More recently, the connection between diet and the makeup of the gut microbiota (bacterial colonies) and its connection to the immune system has been recognized.
One of the more interesting environmental findings in the development of autoimmune disorders has to do with MS, which is estimated to affect some 2.5 million people, with women being twice as likely as men to be affected. Multiple sclerosis is what is known as a progressive “demyelinating disease” of the central nervous system (brain and spinal cord) and is characterized by lesions that are most likely caused by an autoimmune response to self-produced antigens.
Your nerves and spinal cord are protected by a layer of insulating material known as myelin, similar in function to the insulation on an electric wire. If this myelin later is disrupted, as it is in MS, electrical transmissions cannot happen as normal and symptoms can include vision loss, fatigue, weakness, muscle paralysis, and an inability to coordinate movements. MS has long been associated with living at higher latitudes as well as living in well-developed countries.
Several theories have been proposed to explain this, but one of the most compelling is that people who live at higher latitudes, such as Northern Europe, have less exposure to sunlight. Also, people who live in more well-developed, industrialized countries, tend to spend less time outdoors. Sunlight, as you may recall, is necessary for the synthesis of Vitamin D in human skin. Studies have shown that MS patients, as well as patients with some other autoimmune diseases, do indeed have low levels of Vitamin D in their bloodstreams.
Besides sun exposure, the addition of fatty fish to the diet, such as salmon and sardines, is a great source of natural Vitamin D. The incidence of MS has been found to be lower in coastal areas, which one would expect if the Vitamin D hypothesis is correct. Interestingly, the addition of fish oils as a dietary supplement apparently does not have an effect on the development or course of MS.
So, the takeaway here is that to reduce your chances of developing an autoimmune disorder, eat a nutrient-dense diet, rich in oily fish, and get outside under the sun for recreation, exercise, and fun!