By now, you’re probably aware that for some people, eating gluten can cause a host of digestive problems, from stomach pain to gas to bloating. But did you know that gluten can also affect the brain?
Mounting evidence suggests that gluten, the glue-like protein that binds certain foods together, can cause a range of neurological symptoms, from nerve pain and trouble talking, to brain fog and headaches.
Read on to learn about the cognitive effects of gluten, who is most at risk, and what to do about it.
What Is Gluten?
Gluten is a protein naturally found in grains such as wheat, rye, and barley. It’s the reason that flour stretches and helps hold baked goods together and keep their shape. Gluten is often added to processed foods to improve their texture and flavor.[1]https://pubmed.ncbi.nlm.nih.gov/28244676/
Most people can tolerate gluten, but around 1 in 100 Americans suffers from celiac disease, an autoimmune disorder that affects the digestive process. When people with celiac eat foods containing gluten, their immune system treats the gluten as a deadly invader, releasing antibodies and other molecules that damage the small intestine and block their body’s absorption of nutrients. The immune system starts to attack healthy cells, in this case, the villi, millions of finger-like structures that line the inside wall of the gut that are crucial to nutrient absorption.
If left untreated, celiac patients can develop bloating, stomach pain, diarrhea, gas, joint pain, skin issues, and fatigue. The long-term effects can be severe, and celiac disease can lead to other autoimmune disorders, osteoporosis, neurological conditions, and in some cases, cancer.
But even if you don’t suffer from celiac, you may still have a sensitivity to gluten. People with non-celiac gluten sensitivity may still feel crummy after eating gluten and experience symptoms like tiredness, brain fog, headaches, and even depression and anxiety. [2]https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4406911/
How Does Gluten Affect the Brain?
Scientists are beginning to pay more attention to what is known as the gut-brain axis — the idea that your gut and brain are constantly communicating with each other. [3]https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4367209/ If your gut microbiome is out of whack, your brain health can take a hit. Research shows a link between gut issues and various behavioral and mood disorders, including depression, anxiety, and neurodegenerative disorders such as Parkinson’s and Alzheimer’s. [4]https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4662178/ [5]https://pubmed.ncbi.nlm.nih.gov/32282304/
Research shows that gluten can change the brain of those with celiac disease. In a 2020 study, people with celiac disease showed slower reaction time, higher anxiety and depression, and damage to cerebral tissue compared to participants without celiac.[6]https://www.sciencedirect.com/science/article/abs/pii/S0016508520302390
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In one study, cutting out gluten for a year lowered anxiety in 35 participants with celiac disease.[7]https://pubmed.ncbi.nlm.nih.gov/11346203/
Typically, those who show neurological symptoms have no digestive symptoms.[8]https://pubmed.ncbi.nlm.nih.gov/20170845/
The impacts are less clear for those not suffering from celiac or gluten sensitivity. A 2021 study followed more than 13,000 women for 28 years and found that gluten had no impact on cognitive function.[9]https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2780271
The most common neurological symptoms of celiac and gluten sensitivity are gluten ataxia and gluten neuropathy.[10]https://www.karger.com/Article/Abstract/369509 [11]https://jamanetwork.com/journals/jamaneurology/fullarticle/789587
Gluten Ataxia
Gluten ataxia is a rare autoimmune condition in which the antibodies your body releases when you eat gluten attack a part of your brain called the cerebellum, which plays a major role in physical movement.[12]https://www.ncbi.nlm.nih.gov/books/NBK538167/
Symptoms may at first be mild but steadily get worse over time. They include:[13]https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6412791/
- Unsteadiness and clumsiness
- Difficulty controlling your arms and legs
- Poor coordination
- Problems with talking and slurred speech
- Slow eye movements
- Trouble swallowing
Gluten Neuropathy
Gluten neuropathy, a form of peripheral neuropathy, is a condition in which gluten antibodies cause nerve damage to the hands and feet.
In a 2006 study of those with neuropathy, 34% of participants showed high gluten antibodies compared to 12% of those without neuropathy. Biopsies showed that 80% of participants carried genes that predispose them to celiac disease.[14]https://jnnp.bmj.com/content/77/11/1262
Symptoms typically start in the hands and feet but can be felt in other parts of the body.[15]https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6412791/#B11-nutrients-11-00380 They include:
- Tingling
- Numbness
- Pain
- Burning feeling
- Weakness
Who Is Most at Risk?
Celiac is an inherited disease, which means that if you have a blood relative with it, you’re more likely to develop it.[16]https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4535670/ If you don’t have one of the two genes that predispose you to celiac, then your odds of developing it are extremely low.
Around 10% of people with celiac disease will develop neurological symptoms. [17]https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3829244/
A growing body of research shows that celiac patients who have gluten antibodies for a protein called transglutaminase 6 (TG6) are at higher risk of brain shrinkage, ataxia and neuropathy.[18]https://pubmed.ncbi.nlm.nih.gov/30885888/
Nutrient deficiencies may also trigger cognitive issues. One study found that deficiencies in copper, folate, and vitamin E may cause neurological symptoms like ataxia and neuropathy in those with celiac disease.[19]https://n.neurology.org/content/83/20/1789.abstract
What To Do
Get Tested
If you’re dealing with issues like brain fog, headaches, or mental fatigue, talk to your doctor about your symptoms.
You may need to tell your doctor that you suspect gluten intolerance, as some doctors may not consider a dietary correlation with your symptoms.
To test you for celiac, they will first do a blood test to screen for certain antibodies that are higher than normal in people with celiac. The most common test is a tissue transglutaminase, or tTG, which looks for high levels of an antibody that attacks tTG, an enzyme in the intestines.[20]https://pubmed.ncbi.nlm.nih.gov/22326684/ The blood test won’t be reliable if you haven’t been eating regular amounts of gluten.
You could also get a genetic test that scans for cellular receptors called human leukocyte antigens (HLA-DQ2 and HLA-DQ8) — the genes that predispose you to celiac disease. Roughly 97% of those with celiac disease have one of these genes.[21]https://www.hindawi.com/journals/grp/2012/637187/ If your genetic test comes back negative, it is nearly impossible for you to develop celiac disease in the future.[22]https://www.cureceliacdisease.org/wp-content/uploads/341_CDCFactSheets4_GeneticTesting_R11.pdf If your test comes back positive, it doesn’t necessarily mean you have celiac; rather, you have a stronger likelihood of developing it.
If your antibody test is positive, your doctor will refer you to a gastroenterologist, who will carry out an endoscopy to obtain tissue samples from the small intestine. They will be looking for damage to the villi or inflammatory cells.
If the sample shows signs of celiac disease, your doctor will recommend that you follow a strict gluten-free diet for life. As of now, cutting out gluten completely is the only way to switch off the body’s immune response to it and reduce symptoms.
The good news is, gluten-free products have flooded into the market over the last decade or so, and it’s easier than ever to satisfy nearly every craving you may have with a gluten-free replacement.
Temporarily Eliminate It
There’s no test for gluten sensitivity, but if you’re feeling mentally foggy or drained, try cutting out gluten completely from your diet for 5-6 weeks.[23]https://waojournal.biomedcentral.com/articles/10.1186/s40413-016-0139-7
If your thinking starts to feel clearer and your brain fog lifts, then gluten may be the culprit. Slowly start reintroducing gluten into your diet. If you start to feel worse, then you may benefit from permanently avoiding gluten, or eating it only occasionally.
Check for Unlikely Sources of Gluten
Gluten isn’t only present in bread. A wide variety of processed and unprocessed foods contain it. Some less common foods where gluten may be lurking include:
- Soy sauce
- Beer
- Salad dressings
- Cereal
- Potato chips
- Deli meats
- Roasted nuts
- Condiments
Another place to look – your medicine cabinet. Although most medications are gluten-free, some medications use gluten to bind the pills together.
The bottom line — a lot of people tolerate gluten, while others have a hard time with it. Check with your doctor if you have any symptoms.
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