Does the consumption of gluten-containing grains contribute to psychiatric disorders such as schizophrenia?
Believe it or not, this question has been asked for well over 60 years by researchers who stumbled upon evidence that the removal of gluten from the diet results in improved symptoms, or conversely, that gluten grain consumption leads to higher prevalence of both neurological and psychiatric problems.
Reports of the resolution of emotional disturbances after the institution of a "gluten free" diet exist in medical literature at least as far back as 1951.[i] In 1954, Sleisenger reported to have found three schizophrenics among a group of thirty-two adults with celiac disease,[ii] and in 1957, Bossak, Wang and Aldersberg reported discovering 5 psychotic patients among 94 patients with celiac disease.[iii] The initial recognition that celiac disease, or at least gluten sensitivity, occurred at a far higher prevalence among schizophrenics than the healthy, opened up the door to more elaborate investigations.
Wartime Reduction In Gluten Grain Rations Reduces Schizophrenia Prevalence
For instance, in 1966, a remarkable epidemiological study was published in The American Journal of Clinical Nutrition titled,"Wheat "Consumption" and Hospital Admissions for Schizophrenia During World War II," which sought to confirm the possible relationship between schizophrenia and celiac disease by investigating the reported decrease in the number of admissions to mental hospitals during some wars.
The author of the study, F. C. Dohan, M.D., looked at the number of women admitted to the mental hospitals in Finland, Norway, Sweden, Canada and the United States before and after World War II. These figures were then compared to volume of wheat and rye consumed during those two periods. As Dohan explains:
The percent change in the mean annual number of first admissions for schizophrenia to the hospital in each of the five countries from the respective pre-war mean was compared to the percent change in the "consumption" of wheat and wheat plus rye."
The results can be view in the figure below:
As you can see above, the percent change from prewar values during World War II in the number of patients admitted to hospitals for the first time with schizophrenia in five countries was found to be significantly correlated to the percent change in the amount of wheat and wheat plus rye consumed. As gluten grain rations decreased, so did the worldwide rate of first-time admission to psychiatric institutions.
Increasing Body of Research Implicates Gluten Grains in Schizophrenia Pathogenesis
Since then, a number of studies have been published linking the consumption of gluten-containing grains to schizophrenia:
- Schizophrenia Bulletin, 2011: Persons with schizophrenia have higher than expected titers of antibodies (7 fold increased prevalence) related to celiac disease and gluten sensitivity.[iv]
- Schizophrenia Research, 2010: Individual with schizophrenia have a novel immune response to gliadin distinct from those with celiac disease (i.e. absence of antibodies to the transglutaminase enzyme and the HLA-DQ2/DQ8 genetic locus of susceptibility.[v]
- Acta Psychiatra Scandinavica, 2006: A review of the literature found a drastic reduction, if not full remission, of schizophrenic symptoms after initiation of gluten withdrawal has been noted in a variety of studies.[vi]
- Biological Psychiatry, 1984: Only two chronic schizophrenics were found among over 65,000 examined or closely observed adults in remote regions of Papua New Guinea (PNG, 1950-1967) and Malaita , Solomon Islands (1980-1981), and on Yap , Micronesia (1947-1948), who do not consume grains. Researchers noted that when these peoples became partially westernized and consumed wheat, barley beer, and rice, the prevalence reached European levels.[vii]
- Science, 1976: Schizophrenics maintained on a grain-free and milk-free diet challenged with gluten saw interruption of their therapeutic progress. After termination of the gluten challenge, the course of improvement was reinstated.[viii]
New Research Confirms Gliadin-Schizophrenia Link
The latest study to confirm the gluten-schizophrenia link was published this month in the World Journal of Biological Psychiatry and titled, "Elevated gliadin antibody levels in individuals with schizophrenia." Researchers compared the blood work of 950 schizophrenics with 1,000 healthy controls. They discovered that the odds ratio of having anti-gliadin IgG antibodies was 2.13 times higher in schizophrenics, indicating that t the least schizophrenics are more likely to experience an adverse immune response to wheat proteins.
Gliadin is the alcohol soluble complex of proteins found within what is known colloquially as gluten (the term is misleading as wheat technically contains over 23,000 different proteins, not one), and is considered the primary immunotoxic class of proteins in wheat. For instance, in celiac disease, a genetically mediated immune process unfurls where upon exposure to gliadin, the enzyme tissue transglutaminase modifies the protein, and the immune system cross-reacts with the small-bowel tissue, causing an inflammatory reaction that results in the destruction of the intestinal villi.
The discovery of antibodies to gliadin in the blood of both celiac disease patients and schizophrenics implies several things:
- The Wheat Protein Gliadin Doesn't Break Down During Digestion: Undigested wheat-derived macromolecules can act as antigens, provoking an antibody-mediated immune response, particularly if they get through the intestinal lining and into the blood. The fact that antibodies to wheat protein gliadin can be found in the blood indicates that it is not being fully broken down into constituent amino acids.
- Wheat Proteins In the Blood Stimulate Auto-Immunity: The presence of gliadin in the blood also indicates intestinal permeability. It turns out that gliadin has been found to up-regulate the protein zonulin in the gut of those either with or without celiac disease, which essentially opens "pandora's box" of intestinal permeability, and subsequent autoimmunity.[ix] In another essay, we also described the intestinal permeability generating effects of wheat lectin, also known as Wheat Germ Agglutinin (WGA) – [see Opening Pandora's Bread Box]
- Wheat Protein May Cause The Immune System To Attack the Nervous System: Anti-gliadin antibodies appear to cross react with neurological self-structures, which may explain how they contribute to schizophrenia. A study published in 2007 in the Journal of Immunology found that anti-gliadin antibodies bind to neuronal synapsin I, a protein found within nerve terminal of axons, which the study authors believe may explain why gliadin contributes to "neurologic complications such as neuropathy, ataxia, seizures, and neurobehavioral changes."[x] Another example of anti-gliadin antibodies possibly contributing to the formation of autoantibodies against neurological self-structures is in autism. A 2004 study in Nutritional Neuroscience found that children with autism show antibody elevations against gliadin and cerebellar (brain) proteins simultaneously. In other words, wheat proteins may simulate antibodies that cross-react, resulting in neurological damage.[xi] Learn more on the topic by reading our article: Wheat: A Missing Piece In the Autism Puzzle