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Originally published on www.kellybroganmd.com
Could there be a food-based cure for schizophrenia, bipolar, and depressive disorders? It is my firm conviction that diet – both what it may be deficient in as well as its potential toxicity – can cause what we label as mental illness. In medical school, we learn about the mental repercussions of nutrient deficiencies such as Beriberi (thiamin), Pellagra (niacin), and B12-deficiency induced dementia. We know that minerals such as magnesium and zinc are critical cofactors for basic functions, and that fatty acids are essential in the support of cell membrane health.
I believe in a partnership with my patients; however, my most paternalistic mandate, as a psychiatrist, is that of a gluten and casein free dietary trial.
What's that? they often ask.
Gluten, from the Latin, "glue" is a composite of proteins comprised of gliadin and glutenin, found in wheat, with similar 'glutinous' proteins known as prolamines found in related grains such as rye (secalin), corn (zein), and barley (horedin), and casein is the name for a family of proteins in mammalian milk. How does this relate to the average patient scheduling an appointment with a psychiatrist? Is it possible that our modern, post-industrial foods – sugar, gluten, processed dairy, and genetically modified soy and corn are conspiring with nutrient deficiencies in an incendiary collaboration that will give rise to gut/brain pathology?
If we accept an inflammatory model of mental illness as having the strongest prospects for guiding preventive medicine interventions and non-toxic, reparative treatment approaches, then we must look at underlying drivers of inflammation.
Immune activating and inflammatory proteins, such as those found in wheat and dairy products, may be critical triggers to consider. One of the mostly highly processed foods in our diet - wheat – is almost exclusively rendered as high-glycemic flour, prepared with sugar, and often genetically modified vegetable oils which are oxidized (rancid). Dairy is homogenized and pasteurized, creating a dead, high-sugar liquid with distorted fats, denatured proteins and unabsorbable or thoroughly destroyed vitamins.
Cross-reactivity and stimulation of antibody response by foods like dairy, oats, corn, millet was examined in this study, suggesting that there is important overlap between grains and dairy. Why and how would these foods cause the problems that they do? There are a number of identified reasons for the disturbances caused by America's darling duo, cheese and bread:
- Fire in the Hole
Lectins in grains and nightshade plants, and proteins in dairy and gluten – namely casein, gliadin and glutenin – can trigger intestinal changes, local, and systemic inflammation. Only recently have we begun to understand how and why. In the case of gluten, zonulin-mediated permeability affords gut contents, including bacterial toxins, access to the bloodstream, where they can play a significant role in driving inflammation and associated psychiatric symptoms, as discussed here.
- Bugging the Bugs
It turns out that diet can be a major determinant of what bugs are most active in our guts, and that the bacteria in our guts may also determine the degree to which we are sensitive to local inflammatory effects of gluten. Gut bacteria are the gatekeepers sounding the alarm by sending inflammatory messages to the rest of the body including the brain.
- Molecular mimicry
When the immune system reacts to a perceived threat such as a food protein, antibodies formed in response may also bind to tissue in glands and organs that share overlapping amino acid sequences. Antibodies can be formed against brain cells, specifically, at times with permanent resultant damage. A study of 400 volunteers found that half of those who reacted to wheat also reacted to brain-based peptides, and the same was found in the subgroup reacting to dairy, suggesting a clustering of reactivity to both brain tissue and these foods.
- The Pleasure of Pizza
Digested proteins from cow dairy and gluten, termed exorphins, interact with opiate receptors in the brain, which accounts for the potentially addictive quality of these foods, and the associated withdrawal when they are taken off the menu.
What does the evidence suggest?
Research into the etiology or cause of syndromes centers around two primary outcomes of interest – associative data that suggests a relationship between an exposure and a cluster of symptoms (% of people with gluten sensitivity who have psychiatric problems), and treatment data that suggests a causative role for that exposure based on the therapeutic effects of its removal (cutting out dairy leads to treatment of depression).
Suspect # 1: Gluten
Assessment of psychiatric pathology in celiac patients has supported a statistically significant incidence of anxiety (panic), depression (21% in this study), bipolar patients, and schizophrenia (27% in this study). When we consider the available evidence base, we have to zoom out to appreciate its inherent limitations – antibody-mediated immune response is just one mechanism by which the body can be alerted to a perceived threat. If you ask to be screened for gluten intolerance, that screening will typically include antibodies to only alpha gliadin, endomesial antibody, and one type of tissue transglutaminase. This testing neglects the role of the innate immune system in non-celiac gluten enteropathy, an inflammatory disorder that often has extra-intestinal manifestations. According to gluten-researcher, Dr. Hadjivassiliou, "gluten sensitivity can be primarily, and at times, exclusively, a neurological disease".
Since 1953, there have been observations linking schizophrenia and Celiac disease, suggesting that the role of the immune system plays prominently in this poorly understood disorder.