Nutritional Psychiatry: The Link Between Diet and Mental Health

Most people don’t feel particularly happy after they consume a fast-food meal. For some, this might be caused by disappointment or guilt surrounding an unhealthy dietary choice, but for others, it might be the components of the meal itself creating a worse mood.

Recent discoveries in the field of nutrition science have established a compelling link between the food we consume and our mental health. Yet, healthcare providers often overlook diet as a means of treating psychological disorders. What do we actually know about nutritional psychiatry, and can patients suffering from mental disorders use nutrition to feel better?

The Link Between Mental Health and the Microbiome

One of the most important neurotransmitters — not just for mental health but for overall well-being — serotonin, is responsible for stabilizing a person’s mood, regulating sleeping patterns and encouraging feelings of happiness. Humans produce about 95 percent of the body’s serotonin in the gastrointestinal tract. Here, the neurotransmitter helps the hundreds of millions of nerve cells in the stomach and intestines break down food during digestion, and it provides a mood boost while doing so.

Also within the gastrointestinal tract is the microbiome, or billions of bacteria that also assist in breaking down food. The foods a human consumes influences the types of bacteria present in their microbiome — which also has an effect on the levels and effectiveness of neurotransmitters. So-called “good” bacteria protect the lining of the gastrointestinal tract, while the “bad” bacteria can cause inflammation, bloating and pain. What’s more, the helpful bacteria improve the absorption of nutrients and maintain the activity of neural pathways between gut and brain, ensuring that serotonin functions to improve one’s mood. In contrast, when too many harmful bacteria proliferate in the microbiome, serotonin’s effectiveness can falter.

Fortunately, it is possible to influence the balance of good and bad bacteria within the microbiome, and in doing so, one can have greater control over one’s mental and physical health. Though the field of nutritional psychiatry is relatively new, all healthcare providers can enroll in a nutrition science course to learn the basics of nutrition and its links to disease prevention. Then, healthcare providers can build nutrition into a broader treatment plan for mental illnesses to ensure holistic healing.

Strategies for Increasing Gut Health for Emotional Wellbeing

When serotonin levels are low, it might be useful to consider altering one’s dietary practices to encourage the proliferation of good bacteria in the microbiome. Some strategies for boosting gastrointestinal health through nutrition and thereby fostering a positive environment for serotonin production and uptake include:

Eat probiotic and fiber-rich foods. Probiotic foods are those that contain the healthy bacteria one’s body needs to break down nutrients in the gut. Fermented foods, like yogurt, sauerkraut and kombucha, grow these bacteria and shuttle them into the microbiome when they are consumed. Yet, once good bacteria are in the microbiome, they need to be sustained — which is where fiber comes in. Fiber is a prebiotic, meaning it is an essential nutrient for keeping bacteria alive. Whole grains, fruits and vegetables are the best sources of dietary fiber.

Limit alcohol intake. Alcohol is strongly acidic, and frequent alcohol use can make the gut an inhospitable place for bacteria while degrading the lining of the gastrointestinal tract and increasing inflammation. Gut experts recommend limiting intake to ensure two to three fully alcohol-free days each week. When one does drink alcohol, it should be with food.

Reduce sugar and other sweeteners. Sweet foods can be detrimental to the microbiome by causing dysbiosis, or an imbalance in the types of bacteria in the gastrointestinal tract. Both sugar and aspartame have been linked to “bad” gut bacteria, and it is likely that an overabundance of other sweeteners is similarly detrimental. Enjoying a dessert a few times a week won’t devastate the microbiome, but not every meal should have an unnaturally sweet component.

Quit smoking. Though tobacco smoke has a much more immediate effect on the cardiovascular system, smoking does result in worse health for one’s microbiome. Helpful bacteria are more susceptible to harmful effects of tobacco, so smokers tend to have less-effective microbiomes than nonsmokers have. Quitting nicotine entirely is the best strategy for healing the gut (and the mind) from these effects.

Serotonin is a well-known influencer of mood, yet few realize that so much serotonin is produced in the gastrointestinal tract, not the brain. Nutritional psychiatry aims to harness the power of the gut in generating serotonin and other mood-boosting neurotransmitters, improving the efficacy of mental health treatment in the short and long term.