Anyone who has cozied up with a bowl of mac and cheese after a hard day will agree that food can trigger feelings of happiness and comfort. (Photo: Hispanolistic/Getty)

Why Psychiatrists Are Prescribing Food

The food-mood connection is interesting, but the research is still in its infancy. Here’s what we know.

Christine Byrne is a journalist and soon-to-be registered dietitian.

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Anyone who has cozied up with a bowl of mac and cheese after a hard day will agree that food can trigger feelings of happiness and comfort. The idea that food affects mood is a familiar one. But the emerging field of nutritional psychiatry aims to better understand how overall diet and specific nutrient intake can influence mental health, and apply it in a clinical setting. Psychiatrists and researchers are beginning to consider their patients’ eating habits an integral part of addressing mental health conditions like anxiety and depression, making diet recommendations in addition to providing psychotherapy and (in some cases) prescription medication.

The question of how to put the food-mood connection into practice is a hard one to answer. Nutritional psychiatry research is still in its early stages; so far, most of it points to eating the same type of diet that has long been recommended for physical health. And while a healthy eating prescription sounds simple and harmless enough, too much focus on eating the “right” foods can actually worsen mental health. Here’s what you should know before you start applying any food-mood principles in your own life.

An Up-and-Coming Field

The International Society for Nutritional Psychiatry Research, which coined the phrase “nutritional psychiatry,” was established in 2013. Its founder and president, Felice Jacka, is a professor at Deakin University School of Medicine in Australia, where she researches the link between diet and mental health. The ISNPR now boasts hundreds of members, all practitioners or researchers in psychiatry and related fields. Psychiatrists at prominent institutions like Columbia University and Massachusetts General Hospital are teaching and applying nutritional psychiatry. And media outlets from Bon Appetit to The New York Times are helping popularize the approach.

It’s an exciting notion, but it’s worth approaching the field with some skepticism. The market is filled with companies and people interested in turning a profit: unregulated supplements with names like #Mood Pills and Miss Mellow make vague promises about making you feel happier or lessening your anxiety. Influencers and health coaches make anecdotal—and dubious—claims that the carnivore diet healed their depression and that their diet plans could replace medication.

What you eat, of course, impacts how your brain functions. The brain needs calories to operate, and chemical messengers travel back and forth between your gut and brain via the vagus nerve triggering all sorts of functions, from hormone production to cognition. But researchers are excited about the prospect of finding concrete associations between specific nutrients and mental health.

The most well-supported recommendation in nutritional psychiatry is the use of omega-3 fatty acids to help treat and prevent depression. A 2019 meta-analysis published in Nature analyzed data from 26 existing randomized controlled trials, which included a total of 2,160 participants, all adults with diagnosed clinical depression. The authors found that a daily dose of one gram of omega-3 fatty acid was associated with a significant improvement in depressive symptoms. It’s not totally clear why, but researchers guess that it’s due to both omega-3 fatty acid’s anti-inflammatory effects and their role in producing compounds that support brain function. One important note is that they were looking at omega-3 supplements, not omega-3s from food sources like fatty cold-water fish.

A 2018 review of 213 studies, published in the World Journal of Psychiatry, sought to identify other nutrients that are critical to mental health. The authors identified 12 essential nutrients that, based on existing evidence, seem to be associated with the prevention and treatment of depressive symptoms: folate, iron, omega-3 fatty acids, magnesium, potassium, selenium, thiamine, vitamin A, vitamin B6, vitamin B12, vitamin C, and zinc. The authors then assigned an “antidepressant food score” to various foods, based on their concentration of these nutrients. The highest-scoring foods were leafy green vegetables, organ meats, oysters, clams, and mussels. Other types of seafood, fruits, and vegetables also made the list.

We know these nutrients play a role in the biological pathways related to depression, but the evidence isn’t enough to confidently conclude that getting more of them actually alleviates depression. Just because a nutrient affects a particular pathway, doesn’t mean that it will necessarily have an impact on the outcome (in this case, depression). 

Even though we’re still in the early phases of identifying powerhouse nutrients, research does support the association between mental health and certain eating patterns. There’s mounting evidence that a healthy gut microbiome filled with a diverse set of probiotic (good) bacteria has a positive impact on mood and mental health, among other things. Probiotics produce hundreds of neurochemicals that your brain uses to regulate many physical and mental processes in your body, the American Psychological Association explains. For example, 95 percent of our body’s serotonin (the neurotransmitter that helps regulate mood) is produced by probiotics in the gut. The best way to support your probiotic bacteria is to feed them prebiotic fiber, found in whole, plant foods like fruits and vegetables. On the other hand, processed foods and simple sugars can feed less-healthy gut bacteria, so too much of these things can cause harm.

2019 meta-analysis published in Molecular Psychiatry found an overall association between a Mediterranean diet—high intake of plant foods, moderate intake of fish and poultry, and olive oil as the main source of fat—and lower risk of depression, although not every study they included supported this conclusion. The same review found a loose, inconclusive link between eating fewer processed foods and a lower risk of depression.

Putting Theory into Practice

Umadevi Naidoo, a psychiatrist and the director of nutritional and lifestyle psychiatry at Massachusetts General Hospital, became interested in nutritional psychiatry early in her career. She recommended simple adjustments to one of her patient’s nutrition while treating him for depression. First, he cut back on his daily coffee—which he took with ample creamer and several spoons of sugar. Then, he worked on replacing processed food with more fruits and vegetables. “It really made a difference in his care and his treatment and our therapeutic relationship,” she says.

Now Naidoo works with several patients who suffer from depression and anxiety to improve their overall diet quality, with small tweaks like increasing their intake of whole foods and decreasing their consumption of processed food and added sugar. She checks in with patients about their progress during their regular psychotherapy sessions. In general, this approach is best suited to patients whose diets are high in processed foods to start with, and who are able, financially and otherwise, to make dietary changes. Naidoo says that she’s seen many of her patients’ symptoms improve as a result.

In some ways, it’s similar to the work that registered dietitians do, but Naidoo explains that nutritional psychiatry is just one tool in her practice, and it doesn’t exclude the use of other forms of therapy or medication. Medication can be life-saving for patients with certain mental health disorders. “It is meant to be a complement, and offer more solutions to improving mental wellbeing,” she says.

Keep It Simple

Eating nutritious foods can absolutely support mental health, but some mental health experts worry that prescriptive nutritional psychiatry may encourage patients to be overly vigilant about what they eat. 

“​​The first thing that I think of when I hear about nutritional psychiatry is ‘great—even more pressure to eat perfectly,’” says Kim Daniels, a psychologist who specializes in food and body image concerns. Our cultural fixation on healthy eating is already harmful to many people’s mental health; orthorexia, a damaging obsession with a rigid idea of healthy eating, is now recognized by many experts as an eating disorder (although it’s not yet in the Diagnostic and Statistical Manual used across the field to identify mental disorders). And while nutritional psychiatry doesn’t necessarily mean “eat only nutritious foods all the time,” it can be interpreted this way.

Daniels also points out that the sense of empowerment people may feel with nutritional psychiatry—improving their mood through their own food choices instead of relying solely on medication and psychotherapy—can backfire. Eating seems like something you can control, but being too strict can lead to unmanageable feelings around food, and shame whenever you slip up.

Nutritional psychiatry is still in its infancy. So, for now, think of it as a field to watch. Yes, small changes in how you eat can be sustainable, particularly if they have a noticeably positive impact on your mental health. But there’s so much room for misinterpretation here that it’s worth taking the food-mood connection with a grain of salt.

Food is more than the sum of its nutrients. It is also a source of comfort, joy, and connection, all of which are important for mental health. Too much focus on food can lead to stress, anxiety, and guilt. The only conclusion we can confidently take away from existing research is to keep eating the same type of diet that’s long been recommended for physical health: lots of whole foods, fruits and veggies, and a good balance of macros from a variety of sources. Most importantly, make sure that any diet changes you make—for any reason—leave room for finding pleasure in eating. If you’re going to change your eating habits in the name of better mental health, make sure those changes are actually having that effect.

Lead Photo: Hispanolistic/Getty