Scleroderma: Is Food the Cause?

An acquaintance of mine has scleroderma, and she asked me whether scleroderma has anything to do with diet. The answer to that question seems to depend on whom you ask.

People who haven’t bothered to study the scientific literature on nutrition insist that food has nothing to do with scleroderma. Such idiots deserve to be swatted on the snout with a rolled-up medical journal, because they are spreading dangerous nonsense. On the other hand, the scientists who have dedicated their scientific careers to studying the relationship between food and diet say that the autoimmune diseases, including scleroderma, are strongly related to diet.

The rules for avoiding autoimmune disease are simple: don’t eat your relatives, don’t eat too much fat, and make sure you get plenty of vitamin D. If you get an autoimmune disease anyway, get tested for celiac disease and ask a registered dietitian to help you plan an exclusion diet to see if something you are eating is triggering your problem.

Like other autoimmune diseases, scleroderma is common in the same populations that eat a lot of animal-based foods, which means a lot of animal protein and a lot of fat. On the other hand, autoimmune diseases are rare in populations that eat a low-fat, plant-based diet. Autoimmune diseases are also less common in sunny climates, which suggests that vitamin D (the “sunshine vitamin”) plays a role in preventing them. A diet-related illness called celiac disease seems to increase the risk of other autoimmune diseases, probably because it causes “leaky gut.”

Why do I say “don’t eat your relatives”? Why does eating animal protein pose such a risk of autoimmune disease? It all has to do with a simple fact about DNA. The more closely related two species are, the more alike their DNA is, and the more alike their proteins are. The more alike two proteins are, the more easily they can be mistaken for each other by the immune system.

Let’s imagine that you eat some meat and some potatoes. Ordinarily, the proteins from the meat and the proteins from the potatoes would get broken apart into individual amino acids in your digestive system, and from there the individual amino acids get absorbed into your bloodstream. But let’s imagine that you have a problem with your intestine. It leaks a little, so some fragments of protein from the meat and from the potatoes make their way into your bloodstream before they are completely broken down. The immune system may mistake these proteins for a foreign invader and make antibodies against them. Unfortunately, the proteins from the meat look a lot like your body’s own proteins, so the antibodies against them end up attacking some of your own tissue. The proteins from the potato have no “family resemblance” to anything in your body, so any antibodies that you produce against them will probably not attack your own body. So don’t eat your relatives! Eat plants, instead. However, you may have to be a little picky about which plants you eat.

In people with celiac disease, a protein from wheat (or from rye or barley, both of which are closely related to wheat) triggers the immune system to attack the intestine. Celiac disease can cause a wide range of problems, ranging from malabsorption to “leaky gut.” So you’d expect people with celiac disease to be at particularly high risk for an autoimmune disease like scleroderma. As a matter of fact, they are!

Fat in the diet can also be a problem in autoimmune disease. Roy Swank was warning people about this problem this starting in the late 1940s, but he was largely ignored, even though he published his results the world’s most prestigious medical journals. The role of a high-fat diet in causing multiple sclerosis has recently been “discovered” again. Unfortunately, no one can make a fortune from this discovery, so I’m afraid that it will fall back through the “memory hole” yet again.

If you want to put out a fire, the first thing to do is to stop pouring gasoline on it. Likewise, when you get a diagnosis of a disease that is known to be related to diet, stop eating the foods that are known to provoke that disease! In general, a low-fat, plant-based diet has been associated with a low risk of autoimmune disease. However, a few people may have trouble with wheat or some other plant-based food. Consequently, they should consult a registered dietitian for advice about an exclusion diet. People with autoimmune disease should also ask their doctor, physician assistant, or nurse practitioner to monitor their vitamin D levels and test them for celiac disease.