By Victoria Vernail

Gluten is a class of proteins naturally found in wheat, barley, and rye. Gluten is present in many common foods, including beloved pastas and baked goods, because it helps ingredients stick together. Food that is gluten-free may have a dry and crumbly texture compared to gluten-containing foods because it is missing the key binding agent. Fruits, vegetables, meat, and eggs are naturally gluten free, but more foods are manufactured with gluten-free alternatives. This manufacturing increases the accessibility of a gluten-free diet. Historically, the gluten-free diet is  the only effective way to treat celiac disease (a gluten allergy) and non-celiac gluten sensitivities. Approximately 1% of the global population has celiac disease, but the prevalence of gluten sensitivities is estimated to be near 10% and rising.¹ More recently, the gluten-free diet is being called the “fad diet of the decade” as celebrities and the media promote the diet as a weight-loss trend. Therefore, the gluten-free diet is becoming more popular amongst the general population.

While there is no evidence that gluten causes inflammation in individuals without a sensitivity to gluten, people may choose to eat a gluten-free diet. A gluten-free diet might help a healthy person think they feel better by promoting other inherently healthy habits like reducing consumption of processed food or reading food labels. It is also possible that there is a subset of the population that are unknowingly sensitive to gluten, as gluten sensitivities are becoming more prevalent in the US population.² Therefore, individuals with unexplained symptoms of GI discomfort, anxiety, or brain fog that do not improve with other interventions could potentially benefit from a gluten-free diet. This mindset is supported by neurologist and author of the book Grain Brain, Dr. David Perlmutter. Scientific studies have proven that a gluten-free diet has widespread health benefits in gluten sensitive individuals that extend past the gut (Figure 1).

For individuals with celiac disease and gluten sensitivities, the body mounts an immune response against gluten leading to inflammation in the gut.^3,4 The signs of this immune response include elevated blood levels of gluten antibodies that treat ingested gluten as a foreign invader. The symptoms of celiac disease are not restricted to the gut, as systemic inflammation may contribute to the manifestation of fatigue, joint pain, reproductive problems, neuropathy, and psychiatric conditions. The extraintestinal effects of gluten in celiac disease are at least in part explained by damage to the gut that leads to the spread of inflammation to the brain, perhaps through the gut-brain connection (Figure 2). Therefore, there is a growing interest in reducing gut inflammation to improve neurological conditions. One of the ways to reduce inflammation and stop the immune response in gluten sensitive individuals is to eliminate gluten from the diet, which is shown to improve the following:

1. Anxiety and Depression

Autoimmune diseases, including celiac disease, have been linked to states of increased stress and anxiety. In clinical populations, celiac disease is associated with greater rates of anxiety and depression compared to healthy individuals.⁵ This anxiety and depression could be related to the struggles that come with receiving a chronic disease diagnosis or the physical symptoms that celiac disease patients often experience. Regardless of etiology, studies show that implementing a gluten-free diet may minimize mood disorders in celiac disease patients.⁶ One potential explanation for this improvement in mood, while on a gluten-free diet, is the reduction of inflammation throughout the body as a result of removing gluten from the diet. Activation of the immune system and elevation of inflammatory mediators have been shown to induce depressive symptoms.^7,8 Therefore, a gluten-induced immune response may similarly signal to the brain to promote mood dysregulation. Elimination of gluten from the diet may result in the reduction of inflammation-associated anxiety and depression.

2. Autism and Schizophrenia

Gut inflammation is linked to neurological and developmental disorders. Individuals diagnosed with autism spectrum disorder often experience both intestinal and behavioral symptoms, thought to be due, in part, to a leaky gut.⁹ Clinical research concluded that autistic children who consumed a gluten-free diet had improved symptoms compared to autistic children who maintained a regular diet.¹⁰ Some of these symptoms included stomachache and bloating, social interaction, and stereotyped behaviors. Individuals diagnosed with schizophrenia have seen similar improvements. In a study of schizophrenic patients who ate either a gluten-free diet or a gluten-containing diet, the gluten-free group reported lower negative symptoms (such as avoidance, lack of motivation, and decreased communication).¹¹ It is important to note that while the individuals in these studies did not have a celiac disease diagnosis, they may have been gluten sensitive. The schizophrenic participants studied had antibodies present against gluten which occurs at a higher rate in schizophrenia diagnoses than the general population.¹² The presence of gluten antibodies could mean that there is a relationship between a diagnosis of gluten sensitivity and certain neurological conditions, but the direction of that relationship is not known. Regardless, several studies have demonstrated that a gluten-free diet could be beneficial in reducing both gastrointestinal symptoms and affect in vulnerable populations including autistic and schizophrenic patients.

3. Cognition and Neurodegeneration

            Individuals with celiac disease and gluten sensitivity often report cognitive difficulties including brain fog. In a study that measured cognitive impairment by quantifying information processing, celiac disease patients scored poorly, similar to individuals with a blood alcohol content of 0.5% (0.05 g/100 mL).¹³ The presence of the antibody against gluten was positively correlated with worse cognitive scores. When the same patients followed up after a year of a gluten-free diet, they scored significantly better on the cognitive tests, and they did not show signs of gluten reactivity. In a second study using brain imaging techniques, celiac disease patients had significantly different patterns of brain activity compared to matched controls.¹⁴ These data show that there are physical changes that occur in the brain in response to gluten, which could potentially explain the cognitive deficits in gluten sensitive individuals. Furthermore, gluten-induced cognitive impairment could lead to an increased risk of neurodegenerative conditions. For example, elevated levels of the antibody against gluten are correlated with multiple sclerosis severity.¹⁵ Additionally, while there is no clear correlation between gluten sensitivity and Alzheimer’s disease, increased inflammation is implicated in Alzheimer’s disease progression.¹⁶ Overall, limiting gluten-induced inflammation could improve cognition in gluten sensitive individuals. 

Because of the growing link between chronic inflammation and disease,¹⁷ scientists and the general population alike are searching for ways to reduce inflammation and mitigate the risk of disease. One potential avenue may be by limiting gluten. Many people could benefit from a gluten-free diet because the prevalence of gluten sensitivities in the US is steadily increasing. Gluten sensitivities often manifest with nonspecific and extraintestinal symptoms, making it difficult to diagnose. Even so, it is important to understand that the gluten-free diet was designed specifically for individuals with gluten sensitivities and may not be the best dietary practice for the general population.

TL:DR

• Celiac disease and gluten sensitivity diagnoses are increasing in the US.
• Symptoms of gluten sensitivities can be neurological, in addition to gastrointestinal.
• A gluten-free diet can lessen symptoms of anxiety, mood disorders, and cognitive impairment in celiac or gluten-sensitive individuals.

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References

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