What Are Autoimmune Diseases?
Your immune system plays a critical role in protecting your body against infection and disease. In autoimmune diseases, an unknown trigger causes the immune system to produce antibodies that—rather than fight infections and ward off diseases—attack the body’s own tissue. The following list comprises just a few of the vast number of known autoimmune diseases.
- Inflammatory Bowel Disease (IBD)
- Lupus
- Multiple Sclerosis
- Psoriasis
- Rheumatoid Arthritis
- Type 1 Diabetes
Autoimmune Disease Risk Factors
While the exact causes of autoimmune diseases remain unknown, researchers point to the following noted risk factors, which may occur alone or in combination with others.
- Your genes. Autoimmune diseases tend to run in families; However, the gene inheritance pattern is typically unknown.
- Your sex. Women make up 78% of those affected by autoimmune diseases.
- Having another autoimmune disease. Roughly one-quarter of autoimmune disease patients have multiple autoimmune syndrome, an accumulation of three or more autoimmune conditions.
- Some viruses. Influenza A viruses, measles, and hepatitis C are among the viruses that may trigger the development of autoimmune diseases.
- Some. Certain blood pressure medications, statins, and antibiotics can induce conditions such as autoimmune hepatitis and drug-induced lupus erythematosus.
- Smoking. Tobacco smoking has been linked to multiple autoimmune diseases.
- Obesity. More than 10 autoimmune diseases are known to be associated with being overweight or obese. Research suggests that obesity may promote inflammation while reducing the body’s ability to recognize its own antigens as a non-threat when responding to foreign substances.
How Does Diet Affect Autoimmune Diseases?
“Diet plays a huge role in autoimmune diseases because the immune system is affected by food, and two-thirds of your immune system is located in the gut,” says triple board-certified rheumatologist Micah Yu, MD, who also practices integrative medicine. “Whatever food passes through your gut will talk to your immune system.”
Gut dysbiosis—an imbalance in the gut microbiome, the naturally occurring population of bacteria and other microorganisms within the GI tract—has been closely associated with multiple autoimmune diseases, suggesting that maintaining a healthy gut microbiome benefits autoimmune health.
According to 2021 research published in Lupus Science & Medicine, a dietary fiber called resistant starch (commonly found in bananas, plantains, legumes, and whole grains) may positively affect the gut microbiome of people with lupus. Researchers collected stool samples and dietary information from 12 SLE patients and 15 SLE-related antiphospholipid syndrome (APS) patients to see if resistant starch in their regular diets impacted their gut bacteria makeup. While no one consumed high quantities (more than 15 grams) of resistant starch, medium levels (between 2.5 and 15 grams daily) of dietary starch were associated in SLE with increased Bifidobacterium, which is beneficial to the immune system. And people with APS who ate medium levels of resistant starch exhibited lower quantities of harmful bacteria linked to the disease.
Conversely, ultra-processed foods—such as soft drinks, refined sweetened foods, salty snacks, and processed meats—have been demonstrated to promote gut dysbiosis. A 2017 review published in Food concluded that the resulting imbalance might be associated with an increased risk of at least two autoimmune diseases—Type 1 diabetes and celiac disease—in predisposed children. Additionally, a 2021 study published in The BMJ Suggested that eating ultra-processed foods can significantly heighten the risk of developing IBD.
One reason these foods are so detrimental is that they produce inflammation, which can trigger an abnormal immune response, says Yu. “With your immune system, you have something called immune tolerance, where your immune system’s supposed to see its own cells and just ignore it. But [in autoimmune diseases] over time, because of chronic inflammation, your body will start reacting to its own cells. That’s where [the body] can attack its own joints, its own brain cells, its own nervous system cells, and so forth.”
Yu says that one way to combat that inflammation is by consuming more anti-inflammatory foods. Research has shown that fruits and vegetables are associated with anti-inflammatory properties. And there is evidence that a vegan diet rich in fruits, vegetables, and whole grains reduces inflammation.
A plant-based diet may also reduce autoimmune disease symptoms, such as fatigue. A 2004 study had 24 middle-aged people with rheumatoid arthritis follow a low-fat vegan diet for four weeks. At the end of the study, participants saw a significant reduction in all RA symptoms, except for the duration of morning stiffness. A more recent study, published in Lupus in January 2022, looked at extensive data from 420 SLE patients who completed a 26-question survey on their diets and SLE symptoms. Researchers found that patients “who changed their eating patterns to incorporate more plant-based foods while limiting processed foods and animal products reported improvements in their disease symptoms.”