Nutritional psychiatry is an infant discipline. But it is emerging fast, with exploding research on gut-brain linkage. In brief, the discipline—focused on the use of food, supplements and essential nutrients—offers a great opportunity to treat patients who suffer from depression, anxiety and other mental health disorders.
Although psychiatric patients are known to suffer from poor physical health, largely due to lifestyle, adverse effects of medications and inadequate caring, doctors do not usually prescribe diets for them. Nutritional psychiatry is helping to fulfil this void. On World Mental Health Day, let us take you through some basic research.
The vagus connection
First and foremost, research shows that the food we eat impacts our mood (the SMILES trial, or Supporting the Modification of lifestyle in the Lowered Emotional States, 2017) and that a healthy diet can provide some protection against depression (World Journal of Psychiatry, 2018). That’s because, the stomach and the brain are connected by the vagus nerve, the longest nerve in the body. This nerve can sense the activity of different bacteria that inhabit the stomach—both good and bad—and transfers this information to the brain. The stomach microbes can also activate the vagus nerve. That can play a role on the brain and behaviour.
Good and bad bacteria
The food that you eat can regulate or irritate your stomach environment, altering the balance between good and bad bacteria and leading to diseases. The good bacteria in your stomach are good for you: they break down complex carbohydrates, produce vitamins and nutrients, protect against microbes that cause disease, detox, while helping the immune and nervous systems. Therefore, when the balance goes out of whack, you can get irritable bowel disease, asthma, obesity, metabolic syndrome, diabetes, mood disorders and cognitive problems.
Not just, they can affect your serotonin levels. Serotonin is a chemical messenger, that regulates your mood, appetite and smooth digestion, good sleep, learning and memory, positive feelings and pro-social behaviour. Low serotonin levels can lead to anxiety, depression, irritability, aggressiveness, fatigue, sleep and digestive issues. Most serotonin receptors lie in your intestines. Hardly a surprise, then, that a lack of balance in your gut can affect serotonin levels in your body.
So what should you eat for sound mental health?
Prebiotic and probiotic foods
Have both prebiotic and probiotic foods in your diet, to protect the balance in your stomach environment. A diet rich in onion, garlic, bananas and apples will provide prebiotics—a soluble fibre that feeds the good microorganisms, or probiotics, largely inside the large intestine. Probiotic foods that nourish good bacteria are fermented foods: yogurt with active cultures, pickles, kimchi and so on (without sugar or food colouring, please).
The Mediterranean diet
Recent studies suggest that eating a healthy balanced diet, such as the Mediterranean Diet, may protect against depression. The Mediterranean Diet focuses on eating whole grains, seafood and poultry at least twice a week; consuming beans, legumes, fresh fruit, and leafy greens, nuts like almonds and walnuts, vegetables like cauliflower, healthy fats like olive and canola oil, and less of red meat.
Avoid processed and packaged food
Processed and packaged foods disrupt the gut balance, because they are high in food chemicals. Eat whole foods, instead. Have more fruits and vegetables, instead of fruit and vegetable juices. Eat foods rich in fibre. Instead of sweets, have fresh fruits.