What is Autoimmune Disease? What & Why

What is Autoimmune Disease? What & Why

You’ve likely heard of autoimmune diseases, but do you know what they are, what’s going on in the body, and what causes them? There are over 80 different autoimmune diseases that affect people from all walks of life, from young children to the elderly. While some autoimmune diseases are largely genetic and occur from birth or the early years of childhood, some aren’t diagnosed until later.

So, what causes the body to act this way, and what is going on in the body?

What is autoimmune disease?


An autoimmune condition occurs when the body attacks its own tissues. This is caused when the body cannot distinguish its own cells from pathogens or when it cannot regulate the severity of the response.

The function of the immune system is to protect against bacteria and viruses, and when the immune system recognizes these invaders, it releases cells to attack them. Unfortunately, in some cases, the immune system cannot differentiate between the body’s cells and foreign cells. Autoimmune diseases can affect almost any part of the body.

There are over 80 different autoimmune diseases and many of their symptoms overlap, so they can be difficult to diagnose. You may already know a few common autoimmune diseases; the most well-known autoimmune diseases are:

  • Type 1 Diabetes: here, the immune system attacks the pancreas’ insulin-producing cells, often resulting in damage to blood vessels. Type 1 diabetes is also known as “childhood diabetes” because it is diagnosed early in life.

  • Rheumatoid Arthritis: this involves an attack on the joints, causing pain, stiffness, and redness around the knees, elbows, ankles, and wrists. Rheumatoid arthritis differs from osteoarthritis in that it can affect people in their 30s.

  • Multiple Sclerosis or MS: this issue damages the protective coating around the nerve cells. This coating is called the myelin sheath and damage to this system hinders the speed of the communication between the brain and spinal cord to the rest of the body. The most common result of MS is trouble walking.

  • Psoriasis: while not always extremely painful, psoriasis is an uncomfortable skin condition caused by an excessive supply of skin cells. This results in skin inflammation, redness, and white ‘scales’ on the skin.

  • Celiac Disease: many people with celiac disease deal with symptoms for a while without being diagnosed. Despite this, around 2 million Americans have celiac disease and around 1% of people globally have celiac disease. Those with celiac disease cannot tolerate foods that contain gluten, which is the protein in wheat and other grain-based foods. When gluten hits their small intestine, their immune system becomes inflamed.

Other autoimmune diseases include lupus, inflammatory bowel disease, Hashimoto's thyroiditis, Addison’s disease, Sjögren’s syndrome, Systemic lupus erythematosus, Graves’ disease, and pernicious anemia.



Where do autoimmune diseases come from?


Doctors still aren’t sure why the immune system is liable to misfire, but certain people are more likely to get an autoimmune disease than others. One study found that women are twice as likely as men to develop an autoimmune disease, with the disease emerging between ages 15 to 44.

While there is still much research needed on the topic, scientists often agree that there are several primary causes of autoimmune diseases:

  • Genetic predisposition: Current research has demonstrated there are many genes that have been shown to increase the risk of autoimmune diseases. Although the cause is unknown, there is a connection between genetic predisposition and environmental triggers in autoimmune diseases.

  • Poor gut health: There is growing research into the link between gut microbiome health and autoimmune diseases. The gut helps the body to extract nutrients and expel toxins from the body. When the lining of the gut is inflamed, the microbiome is imbalanced, the body is stressed or excess alcohol is consumed, the gut bears the brunt of it all. Issues like this can lead to a leaky gut in which toxins leak into the bloodstream and cause the body to combat inflammation against itself.

  • Stress: Those with stress-related disorders and mental health issues have been shown more likely to be diagnosed with autoimmune conditions. Stress can impact the body in a variety of ways and cause an imbalance in our bodies. This could be a core reason why it may trigger autoimmune conditions.

If the immune system’s function is to protect the body, why does it attack the body?


As we learned above, genetics can influence a person’s likelihood to develop any health issue, including autoimmune diseases. Alongside sex, ethnicity can also play a role in a person’s likelihood of developing certain autoimmune diseases.

For example, Caucasian people are less likely to develop lupus than members of the African-American and Latin communities. Lupus also runs in families, as does multiple sclerosis. While the same disease is not guaranteed for every member of a family, they may inherit a vulnerability to certain health conditions.

But it’s not just genetics that can play a role in the development of autoimmune diseases. Infections and exposure to modern chemicals and pollutants may also influence people’s vulnerability.

Another idea that is becoming increasingly popular is something called the hygiene hypothesis. The outbreak of COVID-19 has meant that we’re receiving more vaccines and using antiseptic and disinfectant products with a much higher frequency. While this has been necessary to curb the spread of the virus, it has meant that our children aren’t exposed to as much bacteria as we were as children. This lack of exposure to bacteria could render certain people’s immune systems susceptible to a misjudgment of a harmless substance.

There are many types of autoimmune diseases, all brought on by different issues and all bringing with them a host of unique challenges. From joint swelling and stiffness to weight loss and hair loss, autoimmune diseases can cause a significant amount of discomfort. While some autoimmune diseases are unavoidable, there is a strong link between some autoimmune systems and your diet.


Dr. Nancy Rahnama, MD, ABOM, ABIM, is a medical doctor board certified by both the American Board of Obesity Medicine and the American Board of Internal Medicine. Her specialty is Clinical Nutrition, that is, the use of nutrition by a medical doctor to diagnose and treat disease. Dr. Rahnama has helped thousands of people achieve their goals of weight loss, gut health, improved mood and sleep, and managing chronic disease.