Effect of Gluten on Alzheimer's Disease Risk

Although most people consider celiac disease and non-celiac gluten sensitivity to be conditions that involve mainly their digestive systems, research indicates these conditions actually may have wide-ranging effects on your body, including your joints, your hormones, and even your brain.

Given that, could they contribute to, or even cause, Alzheimer's disease and dementia?

Fortunately, the evidence from medical studies so far says gluten ingestion does not raise your risk of dementia or Alzheimer's disease if you have celiac disease or gluten sensitivity.

The Evidence

Dr. Alessio Fasano, head of the Massachusetts General Hospital's Center for Celiac Research and Treatment, tells VerywellHealth.com that the most recent study, conducted in Sweden, indicates that having celiac disease does not increase your risk for dementia and Alzheimer's disease.

The study looked at some 8,846 people age 50 and over who had been diagnosed with celiac disease using endoscopy and an intestinal biopsy to confirm celiac-related intestinal damage and compared them to 43,474 people who didn't have celiac disease. The median age of study subjects was 63 years old.

Over a follow-up period of more than eight years, dementia was diagnosed in 4.3 percent of those with celiac disease and in 4.4 percent of the control group. "It is reassuring that we did not find a strongly increased risk," the authors wrote.

The study did identify an increased risk of a dementia diagnosis during the first year following a diagnosis of celiac disease. However, this risk didn't extend beyond that first year, and the study's authors said it might have been due to the fact that those in the study were carefully evaluated, and medical conditions that already existed but hadn't yet been identified were more likely to be diagnosed and treated. This is a relatively common finding in medical studies, which often uncover existing but previously untreated medical conditions that are unrelated to the condition that researchers are studying.

Vascular Dementia Risk Possibly Raised

More concerning, the study did identify a slightly increased risk of vascular dementia — a type of dementia caused by decreased blood flow to your brain — among people with celiac disease. This is potentially problematic, the authors wrote, because people with celiac disease have a small increased risk of cardiovascular disease, which raises your risk of vascular dementia.

It's possible that this increased risk of vascular dementia could be due to vitamin deficiencies — specifically, a deficiency in vitamin B12, the authors wrote. However, more research will be needed to determine if this is true.

"Our finding of an increased risk of vascular dementia (and not Alzheimer's dementia) may be due to chance but does raise the possibility that vascular dementia may be a long-term consequence of celiac disease analogous to the previously established risk of cardiovascular and cerebrovascular disease," the authors conclude.

More Research Likely on Alzheimer's and Celiac

Although the study from Sweden is strong evidence that celiac disease doesn't raise your risk of dementia and Alzheimer's disease, it probably won't be the last word on the subject. Several older case studies have suggested that gluten ingestion may possibly worsen or even cause Alzheimer's and other forms of dementia in people with celiac disease.

Dr. Fasano says he expects more research to further explore the issue: "To really determine if there is any relationship between celiac disease and late-onset Alzheimer's disease, we need prospective studies that follow individuals over a long period of time. With these studies, we might be able to determine how celiac disease affects the development of Alzheimer's disease or other forms of dementia and cognitive decline."

Another study found that a subset of genes associated with celiac disease and other autoimmune diseases, including rheumatoid arthritis and inflammatory bowel disease, is associated with Alzheimer's disease. The common element appears to be inflammation, the study's authors wrote. But again, more research is needed on those genes and their effects to tease out any possible connection.

No Evidence for Claims in Grain Brain

You may be familiar with neurologist Dr. David Perlmutter, the author of Grain Brain, who blames the gluten protein in the gluten grains wheat, barley, and rye (and to a certain extent, all grains) for declining brain health that in some cases leads to dementia. His prescription is to avoid grain-based carbs, especially gluten.

Dr. Perlmutter's Grain Brain warns that wheat (and other grains) are bad for brain health in everyone, not just those with celiac disease or non-celiac gluten sensitivity. He blames increases in blood sugar linked to grain consumption, saying that this causes insulin resistance and metabolic syndrome, diabetes, and ultimately intellectual decline and dementia.

The problem is, Dr. Permutter's conclusions are supported mainly by his own anecdotal evidence, and aren't backed up by robust medical studies. There's no scientific evidence showing that gluten and/or grains might cause Alzheimer's disease or other forms of dementia.

Inflammation and the Microbiome

One scientist who is studying the question of whether gluten ingestion can contribute to dementia in those who have non-celiac gluten sensitivity is Dr. Mak Daulatzai, a cardiologist and senior medical research fellow at the University of Melbourne in Australia. According to a speculative 2015 paper by Dr. Daulatzai, alterations in your gut microbiome caused by non-celiac gluten sensitivity could lead to body-wide inflammation, which in turn could lead to an increased risk for dementia and Alzheimer's disease.

"Our bodies tolerate most foods and do not mount an immunological reaction," Dr. Daulatzai tells Verywell.com. "However, in the case of gluten, [some peoples' bodies] consider it to be a foreign noxious substance," and react to it. This causes inflammation, he says, and can "induce psychological/psychiatric and neurological manifestations" of non-celiac gluten sensitivity, potentially including dementia.

Dr. Daulatzai says this proposed mechanism for dementia remains speculative and unproven, although he notes his team is working on research that could provide back up for his theory.

A Word From Verywell

Current evidence indicates that having the celiac disease does not raise your risk for Alzheimer's disease or dementia. Meanwhile, there's no medical evidence indicating gluten sensitivity can raise your risk for those two brain-related conditions — although Dr. Daulatzai's research has proposed a possible mechanism for such a link, it remains unproven and speculative.

So while the gluten-free diet has obvious benefits for your health if you have celiac disease or gluten sensitivity, you, unfortunately, can't count on it protecting you from Alzheimer's disease or dementia. Fortunately, there are other ways you can help to reduce your risk of Alzheimer's, including exercise (both physical and mental).