Psychology Today | Georgia Ede, MD
If you are living with a mental health problem of any kind, there are many dietary strategies you can use to try to address the root causes of your symptoms, and the so-called paleo diet is an excellent place to start for just about everyone.
While definitions can vary, I define a paleo diet as a pre-agricultural whole foods diet. Pre-agricultural because it excludes the grains, legumes and dairy products that only became staple foods in most cultures after the birth of agriculture, and whole foods because it excludes the dizzying array of modern processed “foods” which began flooding our markets with the industrialization of our food supply in the mid-20th Century. A paleo-style diet consists therefore of meat, seafood, and/or poultry, fruits and vegetables, nuts and edible seeds, and may also include eggs.
A paleo-style diet has the potential to improve your physical health, but how might it benefit your brain? I am not aware of any clinical studies testing the effects of a paleo-style diet on mental health, but in my nutrition consultation service, I have witnessed significant improvements, particularly in certain individuals with depression, anxiety, and ADHD; and I am not alone. Cutting-edge nutritional psychiatrists who recommend paleo style diets include Dr. Ann Childers in Oregon, Dr. Ignacio Cuaranta in Argentina, Dr. Emily Deans in Massachusetts and Dr. Kelly Brogan in New York.
How might these whole foods dietary patterns work to improve psychiatric disorders in some people? Let’s take a look at how the removal of specific food groups may work to support better brain health.
No Grains & Legumes
Grains and legumes have only been major staple foods in most human diets for about 10,000 years, which in the grand scheme of nearly two million years of human evolutionary history is actually a very short period of time.
Grains and legumes have a lot in common. All grains and legumes are seeds, most of which are considered inedible in their natural state. Eaten raw, most grains and legumes are poor sources of nutrients and can even make you very sick. Why is that?
No self-respecting creature wants to be eaten—and plants are no exception. Plants defend themselves with sophisticated chemical weapons designed to maim or kill animal cells. All seeds contain plant embryos—the future generation of the parent plant, therefore seeds typically contain high concentrations of the fiercest defensive chemicals in the plant’s arsenal. These include a wide variety of lectins, which can poke holes in animal cells and aggravate the immune system, phytoestrogens which disrupt normal estrogen activity, goitrogens which interfere with thyroid function, and many others.
Furthermore, all seeds contain special substances designed to help them hold on to the nutrients needed for future successful sprouting. These so-called antinutrients include protease inhibitors which interfere with our ability to digest seed proteins, and phytic acid, a mineral magnet that significantly interferes with our ability to absorb iron, zinc, magnesium and calcium—all vital to brain function. The following graph illustrates the rather significant impact of phytic acid on zinc absorption in human subjects. The blue line shows how nicely blood zinc levels rise after consuming zinc-rich oysters alone. Notice that if you eat that same amount of oysters with black beans (legumes), you absorb only about half the amount of zinc, and if you eat them with corn tortillas (corn being a grain), you absorb virtually none of the zinc from the oysters.
Soaking, sprouting, fermenting, or boiling can all help make grains and legumes easier on the body and improve their nutritional value, but none of these processes completely neutralizes all of the problematic compounds in these foods. To learn more, please see my article “Grains Beans Nuts and Seeds.”
Beyond gluten-free, the Paleo diet is free of all grains, not just glutinous grains like wheat. Corn, oats, rice, quinoa, buckwheat, bulgur and all other grains are off the menu. While all of these grains pose risks, grains that contain gluten bear special mention—particularly when it comes to mental health. Strictly speaking, gluten is neither a toxin nor an antinutrient—it is simply a seed storage protein found in wheat, barley, rye, and triticale. We are clearly not well equipped to use this protein for food, as evidenced by the fact that we can’t completely break it down into individual amino acids.
There seem to be important connections between gluten and neuropsychiatric disorders. The best-selling book Grain Brain by neurologist David Perlmutter M.D. has helped introduce the public to the risks to brain health of gluten and other grains. While the relationship between gluten and psychiatric disorders remains poorly understood, and more research is clearly needed, the information we do have suggests clear risks to mental health—at least in susceptible individuals.
Gluten can cause Celiac disease, an autoimmune disease characterized by the production of antibodies against proteins in the small intestine. It is well established that Celiac disease, which affects about 1% of the population, is often accompanied by psychiatric symptoms, particularly depression and psychosis. However, some people without Celiac disease appear to have an abnormal immune reaction to gluten which may also be associated with psychiatric symptoms. For example, people with schizophrenia, autistic spectrum disorder and bipolar disorder are more likely to have antibodies against gluten-derived peptides (short chains of amino acids resulting from the incomplete digestion of gluten) in their bloodstream than those in the general population. Levels of antibodies can be up to four times higher in people with schizophrenia compared to people without schizophrenia. There have been a number of published case reports of people with schizophrenia and autistic spectrum disorders improving on gluten-free diets. This 2015 paper meticulously and convincingly documents the case of a 14-year-old Sicilian girl with severe psychotic symptoms including hallucinations, paranoia, and suicidal thoughts due entirely to non-Celiac gluten sensitivity.
Several studies suggest that gluten may contribute to depression symptoms in some people and in my own clinical experience, I have witnessed several cases of depression, including at least one case of severe bipolar depression, which resolved when gluten was removed from the diet. This certainly does not mean that everyone who eliminates gluten will see their psychiatric symptoms disappear, but if you or someone you love is suffering with mental health problems, it is good to know that this is a distinct possibility in some cases; therefore a gluten-free diet is well worth a try. If you embark on a gluten-free trial, I would recommend abstaining from gluten for a period of at least six weeks and avoiding gluten-free processed foods made with refined carbohydrates such as baked goods and breakfast cereals.
No Refined Carbohydrates
One of the things that all healthier diets share is the avoidance of refined carbohydrates such as added sugars and processed cereals. Eating too many of the wrong carbohydrates too often can cause high blood sugar and insulin levels, which promote inflammation, oxidative stress, and hormonal instability throughout the body and brain. These damaging forces can drive imbalances in the activity of neurotransmitters such as serotonin, dopamine, glutamate and GABA—the very same neurotransmitter imbalances most psychiatric medications are designed to try to correct. If your insulin levels run too high too often, your brain can become insulin resistant, making it harder for insulin to cross into the brain where it is needed to help brain cells generate energy and the vital components they need for daily operations. We are gradually coming to understand that inflammation, oxidative stress, and insulin resistance represent important root causes of many chronic brain illnesses, including many psychiatric disorders.