But the connection between diet and mental health goes a lot deeper than getting a little hangry now and then. About five years ago, I learned this firsthand. After suffering increasingly severe symptoms from a mystery illness (which I’d later learn was Lyme disease) to the point that I could no longer walk more than five minutes without debilitating pain, I had to leave my job in NYC and move back in with my parents. I felt completely isolated and slipped into such a low emotional state that I’d wake up crying and walk (or hobble) through my days in an apathetic fog. But one day, on a whim, I decided to ditch my go-to breakfast cereal and PB&J sandwiches for a veggie-heavy, paleo-style diet to help ease my pain. After a month, my pain was still there, but something I never expected happened—I felt significantly more optimistic—dare I say happy? But as a reminder: this was my personal experience. For other people, Lyme disease can be far more severe and have subsequent mental health implications. In fact, an emerging field of research known as nutritional psychiatry is getting an increasing amount of attention for just this reason, with studies revealing drastic improvements in depression, anxiety, and other conditions among patients who make strategic dietary changes. This has prompted more mental health professionals to start asking their patients a simple yet potentially life-altering question: What have you been eating? “We now have a very large and consistent evidence base…to say that the quality of your diet is linked to your risk of depression in particular,” Jacka said in a recent video she posted to her Twitter page earlier this month. But while the observational evidence between diet and mental health has been clear for several years, only recently have randomized controlled trials shown that improving diet may actually help treat mental health conditions like depression. Case in point: The 2017 SMILES study, led by Jacka, found that moderately to severely depressed people who were coached by a dietitian to follow a Mediterranean style diet for 12 weeks experienced significant improvements in mood compared to people who simply received social support. By the end of the study, around 30% of patients receiving the nutritional support were in remission for their depression compared to 8% of the social support group. Even more recently, a 2019 meta-analysis examined 16 randomized controlled trials looking into the impact of dietary interventions on mental health and concluded that improving diet (namely by increasing vegetables and fiber and scaling back on fast food and sugars) does have a measurable benefit to depression—and to a lesser extent, anxiety. This exciting body of research—along with other research1 examining the effect of individual foods and nutrients on mental health—has prompted a number of mental health professionals to incorporate food into their practice in a big way (even some colleges, like Columbia University, are starting to teach psychiatry students about the food-mood connection). In addition to the usual questions about mental health history, social support systems, and goals, Drew Ramsey, M.D., an assistant clinical professor of psychiatry at Columbia University and a self-proclaimed nutritional psychiatrist, asks patients to describe what they eat. He’s looking for potential nutrient deficiencies/insufficiencies that may affect mental health and exacerbate symptoms as well as insight into a person’s relationship with food. From there, he will guide patients on how to tweak their diet to support their overall mental health, often in conjunction with more conventional modalities like talk therapy and medication. Other practitioners, like nutritional psychiatrist Georgia Ede, M.D., utilize lab work to evaluate metabolic health and nutritional status. “These include blood tests for insulin resistance (sometimes referred to as prediabetes or carbohydrate intolerance) and for nutrient deficiencies such as B12 and iron deficiency,” she says. To help his patients cover their nutritional bases, Ramsey guides them toward the nutrient-dense food groups that most Americans fall short in: leafy greens, brightly colored “rainbow” vegetables, seafood, and fermented foods. From there, he’ll talk with patients about what food within those categories they might enjoy and how to prep and cook them in a simple, joyful way. As a useful tool, he and a colleague created an antidepressant food list1, featuring the plant and animal foods (oysters, salmon, watercress, and spinach to name a few) that contain the highest levels of nutrients proven to help prevent or reduce depression. Interestingly, while plant-based diets are often considered the holy grail, they may not actually be ideal for mental health. “There’s some correlational data that people who eat no red meat, or who eat vegetarian diets, are at a much greater risk of depression,” says Ramsey. “This isn’t popular data among the plant-based crowd, but I think it’s important to consider.” But even so, Ramsey believes it’s his job as a nutritional psychiatrist to help you “feed your brain” regardless of the particular diet you subscribe to—whether that’s Whole30 or vegan. So, if you’re passionate about consuming zero animal products, he’ll provide support and make sure you’re eating and supplementing in a way that supports mental wellness. Other nutritional psychiatrists, like Ede, take a slightly different approach. While she says the most important food rule for mental health is to eat whole foods and avoid modern processed foods (namely refined carbohydrates and refined vegetable oils like soybean and corn oil), she often suggests that patients experiment with eliminating grains, legumes, and dairy as well. “I generally recommend what I call a ‘pre-agricultural whole foods diet’ made up of whole plant and animal foods as one of the best ways to meet the brain’s nutritional needs,” she says. While nixing all grains and legumes may sound odd, she says these foods contain phytic acid, which can interfere with the absorption of important brain-healthy minerals like magnesium and zinc; and lectins, which can damage the gut lining and aggravate the immune system. This approach is enough for most people, but sometimes Ede will go a step further with patients. “For people who have insulin resistance, I recommend a lower-carbohydrate or perhaps even very low-carbohydrate ketogenic version of this same diet.” Several years ago, Ede met with a 40-year-old woman who’d had lifelong symptoms of procrastination, poor motivation, low energy, distractibility, and disorganization that interfered with her work and home life. She was diagnosed with ADHD and prescribed Adderall, which definitely helped but brought uneven benefits throughout the day and caused unpleasant side effects like constipation. She gradually removed grains, legumes, dairy, and most processed foods from her diet, which helped her mood and improved her physical health yet did nothing for her ADHD. But when she agreed to try a ketogenic diet this year, her symptoms began to improve within a few days. “She has since stopped taking Adderall and reports that she functions even better when in ketosis than on Adderall, and without any side effects,” says Ede. Again, this might not be the case for everyone and it’s possible that this woman had a misdiagnosis. The root of ADHD is important to determine, and sometimes patients are treated for ADHD when the real issue is anxiety. In general, ADHD cannot be treated effectively without medication, but anxiety is often more responsive to lifestyle changes like diets. The truth is, every body is a little bit different, and the fact that there are slightly different approaches within the nutritional psychiatry field is likely a really good sign. In fact, according to the experts I interviewed, there are likely three main mechanisms by which the diets described above promote mental wellness: by providing your brain with the nutrients it needs to grow and generate new connections, tamping down inflammation, and promoting gut health. “Our brains continue to make new connections that give birth to new brain cells into our adult life, which is known as neuroplasticity, and the major regulator of this process is a neurohormone called brain-derived neurotrophic factor (BDNF),” says Ramsey. Low levels of BDNF have been associated with both depression and Alzheimer’s, but certain nutrients such as zinc, magnesium, and the omega-3 fatty acid DHA promote the expression of BDNF, through the stimulation of Ketamine. Nixing refined carbohydrates, sugars, and highly processed vegetable oils can help significantly reduce inflammation as well. “Inflammation causes oxidative stress (a form of biochemical stress), which leads to distress signals in the brain that can lead to either depression or anxiety2—or both,” integrative physician Vincent Pedre, M.D., recently told mbg. “On the flip side, we know that the brain will release [pro-inflammatory] cytokines in response to mental stress.” This is why an anti-inflammatory diet, like the Mediterranean diet, which contains fatty fish such as salmon and sardines that are rich in omega-3s can be such a great choice. “DHA is powerfully anti-inflammatory and has been associated not only with reduced Alzheimer’s risk but improvement of depression as well,” says Perlmutter. Finally, by forgoing processed foods and eating more fiber-rich foods (veggies, fruits, legumes, whole grains), prebiotic foods (onions, scallions, garlic, artichokes, leeks, cabbage) and probiotic foods (fermented foods like kimchi, sauerkraut, and kefir), the good bacteria in our gut are able to thrive, leading to an overall healthy microbiome. “Quite a bit of research shows that the microbiome really impacts our reaction to stress and anxiety,” says Lisa Mosconi, Ph.D., a neuroscientist, nutritionist, and associate director of the Alzheimer’s Prevention Clinic at Weill Cornell Medical College. This is in part due to the gut’s impact on GABA, the major inhibitory neurotransmitter that’s been implicated in a multitude of health challenges including anxiety disorders, insomnia, and depression. When our microbiome is healthy and populated with good bacteria, we can better regulate GABA production and benefit from its calming, soothing properties, says Mosconi. Too much bad bacteria, on the other hand, can sort of hijack the GABA system and impair your ability to cope with stress. This is basically true for every neurochemical, but GABA is not the only chemical related to stress balance. Beyond these three mechanisms, diets rich in whole foods are generally just great for maintaining balanced blood sugar, which is key for staying calm, happy, and level-headed on a day-to-day basis. It’s also important not to forget about other lifestyle factors that can make a huge difference in your mental health—and many nutritional psychiatrists and other functional medicine practitioners implement these tools in their practice as well. “These efforts must go well beyond food choices,” says Perlmutter. “The flames of inflammation are fanned by stress, lack of exercise, and most importantly, not enough restorative sleep. Interestingly, each of these is independently associated with risk for both depression as well as Alzheimer’s disease.” The research on nutritional psych is promising, but can be limiting. If you are looking for an alternative, you can try integrative psychiatry that already has incorporated nutrition, as well as infusions and lab work. Either way, the future of medicine is functional and cellularly based.
