Does Food Affect Mental Health?

Joel Davies


We always think about how food impacts our physical health, but what about our mental health? Since food has such an impact on physical health, it would only make sense that food also has a strong impact on mental health. And if so, wouldn’t it also make sense that food affects the onset and severity of mental disorders? The psychological and medical industries have researched this question increasingly in recent years; overwhelmingly, research indicates that the consumption of certain foods and diets significantly influences the onset and severity of mental disorders across the board.

Now, before I explain specifically how, it’s critical to understand that particular foods and diets do not cause mental disorders; some people can eat horrible diets, yet do not suffer from mental disorders, and vice versa. This is because mental disorders are caused by the unique mix of biological factors (ex. genetic predisposition), psychological factors (ex. self-efficacy), and environmental factors (ex. friend group). However, this does not mean that food, much like genetic predisposition, doesn’t significantly contribute towards people’s development of mental disorders.

Food’s strong effect on mental health is likely due to the very intricate and direct connection the gut and brain have with each other. Think about it for a second; when you see a delicious sandwich, you immediately get hungrier, or when you are nervous about a presentation, your stomach gets the butterflies. These day to day instances expose just how intricate the brain-gut connection is. Dr. Mihaela Fadgyas-Stanculete explains, “emerging data reveals the interaction between psychiatric disorders including generalized anxiety disorder, panic disorder, major depressive disorder, bipolar disorder, and schizophrenia and IBS” or irritable bowel syndrome, an intestinal disorder. Because of the brain-gut connection, if you have a digestive disorder or issue like IBS already, you are more at risk to develop any of these mental disorders.

This connection between the gut and brain is so strong because of all the nerve cells, serotonin (and neurotransmitter) production, and bacteria in our gut. According to Harvard’s Dr. Eva Selhub, “95% of your serotonin is produced in your gastrointestinal tract, and your gastrointestinal tract is lined with a hundred million nerve cells.” As serotonin is a neurotransmitter that supports mood stability, appetite, and sleep among other functions, it is pragmatic that diet patterns would pose a significant impact on someone’s mood, especially over a lengthy period. Additionally, Selhub addresses how:
“The function of these neurons and the production of neurotransmitters are highly influenced by the billions of “good” bacteria that make up your intestinal microbiome. These bacteria play an essential role in your health… they provide a strong barrier against toxins and “bad” bacteria, limit inflammation, improve how well you absorb nutrients from your food, and activate neural pathways that travel directly between the gut and the brain.”
Through recent evidence, it is becoming apparent that unhealthy diets are more likely to increase the number of bad bacteria in the gut, and therefore more likely to increase inflammation, malabsorption of nutrients, deactivation of neuronal wiring, and neuronal malfunctioning.

The unhealthy diets discussed in this research are composed of what Selhub says are the “staples of the ‘Western’ dietary pattern.” More specifically, unhealthy diets are high in processed foods, refined grains, other refined foods, fast food, soft drinks, and sugar. Skipping meals and poor appetite are also labeled as unhealthy dieting in this research.
For children and adolescents, a significant relationship is found “between unhealthy dietary patterns and poorer mental health”, increasing the likelihood of developing depression and anxiety as well as “a higher prevalence of attention-deficit/hyperactivity disorder” or ADHD. Many well-conducted studies have also found similar results in adults. Fewer studies have examined the relationship between food and mental disorders such as eating disorders, bipolar depression, schizophrenia, etc., but so far, evidence has shown there is a correlation between diet and these specific mental disorders (such as high sugar intake worsening symptoms of schizophrenia).

Just as diets can strongly influence the onset and severity of mental disorders, they can also prevent or lessen the severity as well. As Dr. T.S. Rao said, “nutritional treatment may be appropriate for controlling and to some extent, preventing depression, bipolar disorder, schizophrenia, eating disorders and anxiety disorders, attention deficit disorder/attention deficit hyperactivity disorder (ADD/ADHD), autism, and addiction”. What one eats could not only keep one’s schizophrenia under control but could altogether prevent it.
So, what are these foods, supplements, and diets that are currently being used to help treat/prevent mental disorders? The most researched are probiotics, omega-3 fatty acids, traditional (and similar) diets, and certain vitamins and minerals. According to Selhub, “studies have shown that when people take probiotics (supplements containing good bacteria), their anxiety levels, the perception of stress, and mental outlook improve, compared with people who did not take probiotics”.

Omega-3 fatty acids also play a significant role in mental disorders, as omega-3 makes up a decent portion of the brain, contributing to its development and functioning. Omega-3 deficiencies, which are more prevalent in Western diets, are linked to mental health problems, as are omega-3 and 6 imbalances. In one randomized controlled study, 77% of depressed seven to fourteen-year-olds who took omega-3 (with psychotherapy) achieved remission while only 56% who took a placebo (with psychotherapy) achieved remission, being one of many studies to capture omega-3’s impact on mental health. Omega-3’s anti-inflammation properties, as well as its aid in dopamine and serotonin transmission, help justify why omega-3 fatty acids are able to help treat/prevent mental health problems.

Traditional diets refer to eating foods that our ancestors ate such as diets high in fruits and vegetables, fish, nuts, healthy fats, and low processed foods. Much research has demonstrated that traditional diets are beneficial towards mental health by treating/preventing mental disorders. “Studies have compared ‘traditional’ diets, like the Mediterranean diet and the traditional Japanese diet, to a typical ‘Western’ diet and have shown that the risk of depression is 25% to 35% lower in those who eat a traditional diet… Scientists account for this difference because these traditional diets tend to be high in vegetables, fruits, unprocessed grains, and fish and seafood, and to contain only modest amounts of lean meats and dairy”. Selhub adds that because most foods eaten in traditional diets are unprocessed, more foods “are fermented, and therefore act as natural probiotics” in traditional diets. Traditional diets also seem to provide a sufficient amount of omega-3 and a balanced ratio of omega-3 and omega-6 fatty acids.

Vitamin and mineral deficiencies have been linked to mental disorders; specifically, B complex vitamins, folate, calcium, chromium, iodine, iron, lithium, selenium, and zinc. More notably, zinc and folate have been shown to increase the effectiveness of antidepressants as other studies have demonstrated B complex vitamins’ ability to improve mood and further function in cognitive disorders, especially in the elderly according to Dr. Rao. The gold standard mood stabilizer, lithium, has also helped treat many mental disorders for decades, especially bipolar disorder.

Though a fairly new area of research, dieting’s influence on mental health has an enormous potential for benefitting millions of lives, especially since dieting and nutritional treatments are extremely cost efficient. It is important not only to expand the research and implementation of dieting treatments, but the education of this research as well.