A layer of special epithelial cells line the intestinal tract. These cells link together by connecting to tight junction proteins, which act as gateways between the intestines and the bloodstream. Part of their job is to allow vital nutrients to pass while protecting the body from compounds that could cause disease. If a malfunction affects the tight junctions, a person can develop intestinal hyperpermeability or leaky gut. It’s important to note that the concept of a leaky gut as a cause of disease is more theoretical than scientifically proven at this point.
Stomach and Bowel Conditions
Many symptomatic conditions affect the stomach and bowels and general digestion. Most of these symptoms also cause nausea and similar issues. Below are some of the more common conditions that affect the stomach and intestinal tract. However, these conditions may not be linked with a leaky gut and have other causes.
- Gastric ulcers grow on the inside of the stomach and cause stomach pain, bloating, and heartburn.
- Infectious diarrhea occurs when bacteria, viruses, or parasites create an infection in the digestive system.
- Irritable bowel syndrome (IBS) has a variety of symptoms, though the most common are abdominal pain, excess gas, diarrhea, and constipation.
- Crohn’s disease is another inflammatory bowel disease that usually develops gradually. Its signs and symptoms include fever, fatigue, diarrhea, and mouth sores.
Some autoimmune diseases, conditions that cause the body’s immune system to attack healthy cells and tissues and cause damage, may result from a leaky gut. However, scientific evidence to support this theory is lacking at this point. Zonulin is a protein that modulates the tight junctions and affects the immune system. Deregulation of the zonulin pathway can cause the gut lining to leak. Some studies suggest gluten is the trigger for pathway deregulation. In general, the damage is reversible if a doctor discovers it early enough and prescribes a gluten-free diet.
Acute Inflammation Conditions
In addition to a possible link with autoimmune disorders, some alternative practitioners and medical doctors theorize that a leaky gut and zonulin dysregulation might trigger inflammation by stimulating the body’s immune response. Inflammation is linked with a variety of health conditions and can damage healthy tissues. However, there is currently no scientific proof that leaky gut causes inflammation. Hopefully, further research will confirm whether leaky gut plays a role in inflammatory conditions.
Chronic Inflammatory Conditions
Unlike acute inflammation conditions, chronic inflammation is slow and lasts for months or years. In some instances, chronic inflammation is triggered by autoimmune disorders such as rheumatoid arthritis. Even if chronic inflammation doesn’t develop into a full-blown condition, it may be a risk factor for chronic health conditions, including heart disease, type 2 diabetes, and some forms of cancer. Many health problems have an inflammatory component.
Neurocognitive and Mood Disorders
A study from the journal Neuroendocrinology Letters points to preliminary evidence that leaky gut may cause neurocognitive and mood disorders. Mood disorders are emotional conditions that feature periods of sadness, joyousness, or a combination of both. Depression is a mood disorder. Neurocognitive disorders are conditions that inhibit mental function, such as autism or Alzheimer’s disease. Many studies have attempted to find links between the gut microbiome and conditions like autism. Some researchers now theorize that leaky gut may play a role in the development of autism. More research is needed to prove such a connection.
Food Sensitivities and Allergies
The immune systems of people with leaky gut are constantly working because many disease-causing materials enter the bloodstream from the intestines. One theory is that a leaky gut might allow proteins from food to enter the bloodstream. The body could, in turn, mount an immune response against those proteins, leading to food allergies. A study in rats and human children linked leaky gut to food allergies. Some doctors now believe that food allergies are linked with a leaky gut, though research is lacking.
Even as early as 70 years ago, medical professionals were theorizing a link between the intestines and skin conditions like psoriasis. Research in recent decades suggests leaky gut may play a role in general acne and inflammatory skin conditions such as eczema, psoriasis, and many others. Most of these conditions feature a scaly or rough patch of red skin that itches, may cause hair loss, and can appear greasy or oily.
The thyroid is a special gland with a butterfly-like shape in the front of the neck. It controls the resting metabolic rate, the rate at which the body burns energy at rest. One theory is that leaky gut can trigger an immune response whereby antibodies attack and damage thyroid tissue so that the thyroid can’t produce enough hormones. The medical term for insufficient amounts of thyroid hormone is hypothyroidism. Fatigue and poor concentration are common with hypothyroidism, as are dry skin, feeling cold, and fluid retention. Some people also experience muscle and joint aches.
One of the autoimmune diseases that leaky gut may be associated with is Celiac disease. It is unclear if this is due to the same mechanism as other autoimmune disorders, but animal studies show an increase in intestinal permeability before Celiac disease develops. The disease affects each individual differently, but the uniting issue is the damage the immune system causes to the small intestine when a person consumes gluten. Most people with Celiac experience diarrhea and abdominal pain, though some individuals face mood disturbances, weight loss, brain fog, and fatigue as well.
Some doctors believe leaky gut can lead to nutritional deficiencies. Some people with leaky gut have low levels of vitamin B12, digestive enzymes, and magnesium, which can lead to various symptoms. In the case of vitamin B12 deficiency, people may experience weakness and fatigue. Doctors sometimes prescribe a multivitamin and probiotics for people with leaky guts.