CNA / THE NEW YORK TIMES – As people around the world struggled with higher levels of stress, depression, and anxiety over the past year, many turned to their favorite foods: ice cream, pastries, pizza, hamburgers. However, recent studies suggest that the sugary, high-fat foods that we often crave when we are stressed or depressed, however comforting they may seem, are the least beneficial to our mental health. Instead, whole foods like vegetables, fruits, fish, eggs, nuts and seeds, beans and legumes, and fermented foods like yogurt may be better choices.
The results come from an emerging area of research known as nutritional psychiatry, which studies the relationship between diet and mental wellbeing. The idea that eating certain foods could benefit brain health, much like how it could benefit heart health, seems to be common sense. In the past, however, nutritional research has largely focused on how the foods we eat affect our physical rather than mental health. For a long time, the potential impact of food on happiness and mental wellbeing has been “practically ignored”, as a team of researchers recently said.
But over the years, a growing body of research has provided fascinating clues about how foods can affect our mood.
A healthy diet promotes a healthy intestine, which communicates with the brain via the so-called gut-brain axis. Microbes in the gut produce neurotransmitters like serotonin and dopamine that regulate our mood and emotions, and the gut microbiome is involved in mental health outcomes. “A growing body of literature shows that the gut microbiome plays a formative role in a variety of psychiatric disorders, including depression,” a team of scientists wrote in the Harvard Review of Psychiatry last year.
Large population studies have also shown that people who eat a lot of nutritious foods report less depression and higher levels of happiness and mental wellbeing. One such study from 2016, in which 12,400 people participated for about seven years, found that those who consumed more fruits and vegetables during the study period scored significantly higher on questionnaires about their general happiness and life satisfaction.
However, large observational studies can only show correlations, not causality, which begs the question: which comes first? Do anxiety and depression drive people to choose unhealthy foods, or vice versa? Are people who are happy and optimistic more motivated to consume nutritious foods? Or does a healthy diet directly brighten your mood?
The first major study shedding light on the relationship between food and mood was published in 2017. A team of researchers wanted to know if dietary changes could help relieve depression. Therefore, they recruited 67 clinically depressed people and divided them into groups. One group met with a nutritionist who taught them to follow a traditional Mediterranean diet. The other group, who served as controls, met regularly with a research assistant who provided social support but not nutritional advice.
At the start of the study, both groups consumed a lot of sugary foods, processed meat, and salty snacks, as well as very little fiber, lean protein, or fruits and vegetables. But the diet group made big changes.
They replaced sweets, fast food, and pastries with whole foods like nuts, beans, fruits, and legumes. They switched from white bread to whole grain and sourdough bread. They gave up sugary cereals and ate cereal and oatmeal. Instead of pizza, they ate pan-fried vegetables. And they replaced highly processed meat with seafood and small amounts of lean red meat.
Importantly, both groups have been advised to continue taking antidepressants or other medications that have been prescribed for them. The aim of the study was not to see if a healthier diet could replace medication, but if it would provide additional benefits such as exercise, good sleep, and other lifestyle behaviors.
After 12 weeks, the mean depression scores improved in both groups, which was to be expected for anyone who participated in a clinical trial that offered additional support, regardless of which group they were in. Depression scores, however, improved to a far greater extent in the group that followed the healthy eating group: about a third of these people were no longer classified as depressed, compared with eight percent of those in the control group.
The results were remarkable for several reasons. The diet benefited mental health even though the participants did not lose any weight. People also saved money by eating more nutritious foods, which shows that eating healthy can be economical. Prior to the study, participants spent an average of $ 138 per week on groceries. Those who switched to healthy eating cut their food bills to $ 112 per week.
The food we recommend was relatively cheap and available in most grocery stores. That included things like canned beans and lentils, canned salmon, tuna and sardines, and frozen and conventional products, said lead author Felice Jacka.
“Mental health is complex,” said the director of the Food and Mood Center at Deakin University in Australia and the president of the International Society for Nutritional Psychiatry Research, Dr. Jacka. “Eating a salad won’t cure depression. But a lot can be done to lift your spirits and improve your sanity, and it can be as simple as increasing your intake of plants and healthy foods. “
A number of randomized trials have reported similar results. In a study of 150 adults with depression published last year, the researchers found that people who followed a fish oil-fortified Mediterranean diet for three months had greater reductions in symptoms of depression, stress and depression after three months compared to a control group Had anxiety.
However, not every study has produced positive results. For example, a large, year-long study published in JAMA in 2019 found that a Mediterranean diet reduced anxiety, but didn’t prevent depression in a group of high-risk people. Taking supplements such as vitamin D, selenium, and omega-3 fatty acids had no effects on depression or anxiety.
Most mental health professionals have not followed dietary recommendations, partly because experts said more research is needed before they can prescribe a specific mental health diet. However, public health experts in countries around the world have begun encouraging people to adopt behaviors such as exercise, sound sleep, a heart-healthy diet, and avoiding smoking that can reduce inflammation and have benefits for the brain. The Royal Australian and New Zealand College of Psychiatrists issued guidelines for clinical practice urging doctors to consider diet, exercise, and smoking before starting any medication or psychotherapy.
Individual clinicians also include nutrition in their work with patients. The psychiatrist and clinical assistant professor at Columbia University College for Physicians and Surgeons in New York, Dr. Drew Ramsey, begins his sessions with new patients by taking their psychiatric history and then examining their diet. He asks what they eat, learns about their favorite foods, and finds out if foods that he thinks are important for the gut-brain connection are missing in their diet, such as plants, seafood, and fermented foods.
Dr. Ramsey published a book, Eat to Beat Depression and Anxiety, in March and founded the Brain Food Clinic in New York to help people with mood disorders improve their diet. He often recites a jingle so people can remember the basics of his dietary advice: “Seafood, vegetables, nuts, and beans – and a little dark chocolate.”
Dr. Ramsey said these foods help promote compounds like brain-derived neurotropic factor (BDNF), a protein that stimulates the growth of new neurons and protects existing ones. They also contain large amounts of fiber, unsaturated fat, antioxidants, omega-3 fatty acids, and other nutrients that have been shown to improve gut and metabolic health and reduce inflammation, all of which can affect the brain.
Dr. Ramsey said he doesn’t want people to believe that the only factor that matters to brain health is food. “A lot of people get their food just right, live very active lives, and still have significant mental health problems,” he said.
But he also teaches people that eating can strengthen them. “We cannot control our genes, who our parents were, or whether we have accidental trauma or violence,” he said. “But we can control how we eat, and that gives people actionable things to do to take care of their brain health on a daily basis.”