At any moment in time, approximately 26% of Americans are struggling with a diagnosable mental illness. So, if you have dinner with three friends, the odds are one of you is not doing well. Most common are depression and anxiety, with a 29% chance of receiving a depression diagnosis in a lifetime, and a 31% chance of experiencing anxiety. Many people suffer from both.
Unfortunately, most of us don’t make the connection between the way we feel and labels like depression and anxiety. We assume that having low energy and being unmotivated or anxious is what everyone experiences.
Dr. Uma Naidoo, a leader in the new field of nutritional psychiatry, Harvard professor, and director of the ground-breaking Nutritional & Lifestyle Psychiatry Program at Massachusetts General Hospital, told Worth, “A family member might tell them they’re acting differently, withdrawn, or losing weight. The same with anxiety. Someone may be waking up with a pit in their stomach and not tie it to anxiety.”
Dr. Drew Ramsey, also a nutritional psychiatrist, and author of Eat to Beat Depression and Anxiety, feels the words ‘depression’ and ‘anxiety’ are bandied about so heedlessly and in so many different contexts, that, not surprisingly, they mean different things to different people. When he and Dr. Naidoo use the words, they refer to diagnoses consistent with the DSM-5, the Diagnostic and Statistical Manual of Mental Disorders, which is the bible used by mental health professionals.
A poor diet can cause more than the triumvirate of diseases everyone can recite verbatim–obesity, diabetes, and heart disease. Also, multiple studies conducted over the last 20 years have demonstrated a connection between a poor diet and mood disorders like depression and anxiety. The problem is that most of us haven’t been paying attention to these studies.
According to Naidoo, Here’s What the Scientists Have Found
Sugar. There’s an astonishingly high correlation between sugar consumption (from foods and sodas) and depression. The reason may be that sugar impedes the body’s ability to make a protein (BDNF) that is essential for brain growth, development, and stress management.
High-glycemic-Load Carbohydrates. Carbs that are easily turned into glucose (sugar) in the body. This includes anything made with white flour (like bread and pasta), white rice, and potatoes. However, low-glycemic index carbs, like beans and most fruits, are not damaging. Several large studies have shown a correlation between consumption of high glycemic load carbs and depression.
Artificial Sweeteners. Not surprisingly, these compounds which are hundreds of times sweeter than sugar, have multiple negative effects on the brain. Aspartame (think Diet Coke) inhibits dopamine and serotonin. Sucralose causes mice to develop the same gut bacteria tied to depression in humans.
Bad Fats. This includes trans fats, which were banned in the U.S. in 2020, and saturated fats. It also includes many fried foods because even ‘good’ fats, reused many times and kept at high temperatures, can become harmful.
Caffeine and alcohol (if anxiety and/or sleep are concerns)
The Gut Microbiome in Anxiety and Depression
Everywhere we turn these days, people are talking about the gut microbiome, the living organisms in the digestive tract that help break down food. We now understand they do much more than that. They create and respond to neurotransmitters that, via the vagus nerve and the circulatory system, are in direct conversation with the brain. Joe Weiss, Gastroenterologist, and Clinical Professor of Medicine at the University of California San Diego, told Worth, “First, you must understand that there are over a trillion species of microbes, and they are everywhere, not just in the gut. They’re floating in the air. We all have unique species on our skin, in our lungs, eyes, ears, etc. They’re even inside cells in the body.” This connection starts when we are embryos. The same cells that become the brain and spinal cord travel through the body to form the enteric (gut) nervous system.
The ones in the enteric nervous system are responsible for most of the body’s serotonin. “Everyone thought serotonin worked only in the brain. We now know that only 5% is in the brain. Over 90% is made in the gut and stays there,” he added.
Other heavy-hitting neurotransmitters made in the gut include dopamine (pleasure, addiction, Parkinson’s if too low, schizophrenia if too high), adrenaline (fight or flight), GABA (calmness, ability to focus), and acetylcholine (memory and cognition).
The above is why psychiatrists like Drs. Naidoo and Ramsey know they can improve many psychiatric conditions with what amounts to a prescriptive diet. Their recommendations overlap because both are using the results of high-level studies to shape their advice.
Leafy Greens. If Dr. Ramsey’s mantra was summed up in three words, it would be “eat leafy greens.” He’s so passionate about this that he’s even published a recipe book entitled Fifty Shades of Kale. He’s softened his stance a little in the decade since the book was published. He now concedes that people who don’t like kale can expand their options to Swiss chard, broccoli rabe, collards, and spinach, all of which contain folate, a B vitamin necessary for the creation of neurotransmitters.
Rainbow Fruits and Vegetables. Dr. Ramsey’s favorite color in this ‘rainbow’ is the reddish-purple created by anthocyanins, an especially nutritious flavonoid (food pigment). Berries contain a lot of anthocyanins so I asked Dr. Ramsey about acai and blueberries, two fruits that have attained superfood status. He was dismissive, saying, “The reason I don’t rely on them is they’re expensive, they’re fetishized, and they’re unreachable to the average consumer. Most importantly, they miss the point. They’re no better than any other berry. All berries tend to be interesting and good for you.”
Seafood. Primarily fatty fish (for their omega-3 fatty acids) low on the food chain (to avoid mercury.) Dr. Ramsey points out that farmed salmon is dyed pink so he only consumes wild salmon. Also good are bluefish and mackerel. Vegans can get omega-3s from algae, although it is not as concentrated as in fish.
Nuts, Beans, and Seeds. A study on depressed and anxious college students in Australia a few years ago showed significant mood improvement in those who, among other things, added a serving of nuts to their diet each afternoon. Beans are an excellent prebiotic, indigestible fiber that feeds healthy large intestine bacteria.
Meat. The first controversial category on this list. Dr. Ramsey was a vegetarian but now believes that moderate consumption of ethically raised meat (grass pastured) is healthy, sustainable, lower calorie than grain-fed meat, and contains numerous essential nutrients including a nourishing fatty acid profile.
Eggs & Fermented Dairy. It’s doubtful that anyone was surprised to see leafy greens on the list. We all know we should eat our vegetables, but many readers probably bristled at the often-maligned foods: eggs and dairy products. However, both psychiatrists told Worth that studies confirm choline (eggs) has been linked to decreased anxiety. Along with choline, eggs are high in high quality protein and B vitamins. Examples of fermented dairy include yogurt and kefir.
Dark Chocolate. The item everyone has been waiting for. It turns out that (dark) chocolate is brain food. A study using U.S. government data from over 13,000 adults showed a 57%(!) reduction in depression in those who ate dark chocolate. However, if the study is to be believed, this group was eating an average of eight ounces of chocolate a day. If you’d like a return for a smaller investment that won’t expand your waistline, less than an ounce a day of dark chocolate reduces salivary cortisol, a stress and anxiety marker.
Although both nutritional psychiatrists agree about which foods are mood enhancers, Dr. Naidoo has a slightly different approach than Dr. Ramsey. In her bestselling book, This Is Your Brain on Food, she focuses on specific foods for specific mental disorders.
For depression, she suggests probiotics (fermented dairy, miso, kimchi), prebiotics (legumes), omega-3 fatty acids (fish, dark leafy greens), and the Mediterranean diet (fruits and vegetables), almost all foods on Dr. Ramsey’s list.
Neither doctor is expecting us to adopt a flawless diet. According to Dr. Naidoo, “It’s about exploring a diversity of foods which help your gut, which helps your mind.” So, if kimchi isn’t your thing, don’t worry. Just increase other foods on the list.
Dr. Naidoo believes anxiety is best controlled by cultured and fermented foods, tryptophan (as a supplement, not from foods), dietary fiber, and omega-3s. The latter two have an anti-inflammatory effect and inflammation is correlated with anxiety. She told Worth, “Poor diet leads to gut inflammation which leads to impairments like depression and anxiety, which often leads people to eat a poor diet. It’s a negative feedback loop.”
A sufferer of anxiety herself, Dr. Naidoo has just published a new book completely devoted to the subject, Calm Your Mind With Food.
I highly recommend both doctors’ books. They’re clear and easy to understand. Most importantly, they’re compelling. I’ve changed my diet since reading them. Maybe you will too.
