Food and Behaviour Research

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Time for a Paradigm Shift on Food and Mood

Odelya Gertel Kraybill

food and brain

Healthy eating patterns, such as the Mediterranean diet, are associated with better mental health than “unhealthy” eating patterns, such as the Western diet.

31/08/2020 - Psychology Today

An increasing number of studies have shown that
psychiatric conditions such as bipolar disorder, schizophrenia, depression, and certain eating disorders are accompanied by immune system dysregulation, inflammation, and high levels of cytokines

In a recent essay, Norwitz et al. (2020) reviewed several studies on this. One reported on a meta-analysis of 69 studies, which demonstrated that patients with a major depressive disorder had a significant elevation of cytokine levels and indications of brain-inflammation postmortem. The authors suggested that psychiatric conditions are linked to neurometabolic inflammatory diseases. 

Inflammation is a defense mechanism triggered in the body when it recognizes an attack and gathers special resources in response. It’s a survival response that the body deploys to protect against a variety of threats, not only infections but also irritants, stress, and physical trauma. When we are exposed to any of these, the body produces small protein cells called cytokines. These small cells facilitate the response of the body to a threat. Their presence can be measured and used to assess inflammation levels in the body (Chang et al., 2010).

Stress and Inflammation

Exposure to childhood adversity has been linked to the development of inflammatory conditions later in life. Stress at a young age is associated with gut inflammation that can lead to problematic mental and physical conditions. The mechanism seems to be that stress hormones affect the organisms living in the gut and their balance with each other. Gut imbalance can lead to damage in the lining of the gut (known as “leaky gut”). As a result, toxins and bacteria “leak" through the intestines and enter the bloodstream. This triggers a reaction of the immune system: inflammation. 

One of the consequences of the sequence set off by adverse childhood experiences (ACEs) is a change in the microbiome. Callaghan et al. (2019) found that "children with a history of early caregiving disruptions had distinctly different gut microbiomes from those raised with biological caregivers from birth. Brain scans of all the children also showed that brain activity patterns were correlated with certain bacteria. For example, the children raised by parents had increased gut microbiome diversity, which is linked to the prefrontal cortex, a region of the brain known to help regulate emotions.”

Neurometabolic Diseases Linked to Psychiatric Conditions

Norwitz et al. (2020) suggested that psychiatric conditions are a set of shared metabolic diseases, including glucose hypometabolism, neurotransmitter imbalances, oxidative stress, and inflammation, that commonly underlie schizophrenia, bipolar disorder, and major depressive disorder and their associated comorbidities. 

Norwitz et al. (2020) emphasize the need for a metabolic approach to therapy in these conditions. One approach they highlight as promising is the ketogenic diet. The keto diet is a high-fat, low-carbohydrate diet that induces the body and brain to use fat and ketone bodies instead of glucose as a source of energy. Historically the ketogenic diet has been an evidence-based treatment for epilepsy. Recently it has been demonstrated to be effective in treating obesity and type II diabetes.  

Norwitz et al. (2020) suggest that it holds promise for the treatment of glucose hypometabolism, neurotransmitter imbalances, oxidative stress, and inflammation, all of which can be metabolic components of psychiatric conditions. Recognition of this, the authors say, is stirring increased interest in the ketogenic diet as a novel treatment for psychiatric conditions, albeit with caution due to its possible impacts on cardiovascular diseases. 

Dietary Inflammation

In another recent report, Firth et al. (2020) suggested that healthy eating patterns, such as the Mediterranean diet, are associated with better mental health than “unhealthy” eating patterns, such as the Western diet. Firth et al. (2020) suggested that the effects of certain foods or dietary patterns on glycemia, immune activation, and the gut microbiome may play a role in the relationships between food and mood. The authors proposed that promoting healthy, nutritious diets while decreasing the consumption of highly processed and refined “junk” foods may provide benefits beyond physical health, including improved psychological well-being.

An All-Wellness Approach Is Needed
 
The evidence of links between food and mood continues to grow, issuing a clear call for a more comprehensive approach to mental health that addresses the physiological and biological as well as the emotional, cognitive, spiritual, and social aspects of wellness. Nutritional psychology and nutritional psychiatry are emerging specialties that can assist therapists in addressing all aspects of wellness.