When it comes to managing stress, we’re often told that the best things to do are to exercise, make time for our favorite activities, or try meditation or mindfulness.
But the types of food we eat can also be an effective way to manage stress, according to research published by myself and other members of APC Microbiome Ireland. Our latest study showed that eating more fermented foods and fiber daily for just four weeks had a significant effect on reducing perceived stress levels.
Over the past decade, a growing body of research has shown that diet can have a huge impact on our mental health. In fact, a healthy diet can even reduce the risk of many common mental illnesses.
The mechanisms underlying the effect of diet on mental health are not yet fully understood. But one explanation for this link could be via the relationship between our brain and our microbiome (the trillions of bacteria that live in our gut). Known as the gut-brain axis, this allows the brain and gut to be in constant communication with each other, allowing essential body functions such as digestion and appetite to take place. produce. It also means that the emotional and cognitive centers of our brain are closely linked to our gut.
While previous research has shown that stress and behavior are also linked to our microbiome, it was not clear until now whether a change in diet (and therefore our microbiome) could have a distinct effect on the stress levels.
This is what our study aimed to do. To test this, we recruited 45 healthy people on relatively low-fiber diets, aged 18-59. More than half were women. Participants were split into two groups and randomly assigned a diet to follow during the four weeks of the study.
About half received a diet designed by nutritionist Dr. Kirsten Berding, which would increase the amount of prebiotic and fermented foods they ate. It’s called a “psychobiotic” diet because it included foods that have been linked to better mental health.
This group received an individual education session with a dietitian at the start and mid-point of the study. They were told they should aim to include six to eight servings a day of prebiotic fiber-rich fruits and vegetables (such as onions, leeks, cabbage, apples, bananas, and oats), five to eight servings of cereals per day and three to four servings of legumes per week. They were also told to include two to three servings of fermented foods daily (such as sauerkraut, kefir, and kombucha). Participants in the control diet received only general dietary advice based on the healthy food pyramid.
Less stress
Interestingly, those who followed the psychobiotic diet reported feeling less stressed than those who followed the control diet. There was also a direct correlation between how strictly participants followed the diet and their perceived stress levels, with those who ate more psychobiotic foods over the four-week period reporting the greatest reduction in perceived stress levels. .
Interestingly, sleep quality improved in both groups, although those on a psychobiotic diet reported greater sleep improvements. Other studies have also shown that gut microbes are involved in sleep processes, which may explain this link.
The psychobiotic diet caused only subtle changes in the composition and function of microbes in the gut. However, we observed significant changes in the level of some key chemicals produced by these gut microbes. Some of these chemicals have been linked to mental health, which may explain why diet participants reported feeling less stressed.
Our results suggest that specific diets can be used to reduce perceived stress levels. This type of diet may also help protect long-term mental health because it targets gut microbes.
Although these results are encouraging, our study is not without limitations. First, the sample size is small due to the pandemic limiting recruitment. Second, the short duration of the study might have limited the changes we observed – and it’s unclear how long they would last. Long-term studies will therefore be necessary.
Third, although participants recorded their daily diet, this form of measurement can be subject to error and bias, especially when estimating food intake. And while we did our best to make sure participants didn’t know which group they were assigned to, they might have guessed based on the nutritional advice given to them. This may have affected the answers they gave at the end of the study. Finally, our study only involved people who were already in good health. This means we don’t understand what effect this diet might have on someone who may not be as healthy.
Yet our study offers exciting evidence that an effective way to reduce stress may be diet. It will be interesting to know if these results can also be replicated in people with stress-related disorders, such as anxiety and depression. It also adds further evidence to this area of research, showing evidence of an association between diet, our microbiome and our mental health.
So the next time you’re feeling particularly stressed, you might want to think more carefully about what you plan to eat for lunch or dinner. Including more fiber and fermented foods for a few weeks may just help you feel a little less stressed.
John Cryan, Vice President for Research and Innovation, University College of Liege
This article is republished from The Conversation under a Creative Commons license.
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