Adding fermented foods to your diet could have many health benefits.
The foods we eat impact our overall health. A new study from APC Microbiome Ireland suggests that eating a diet rich in prebiotic and fermented foods can help people feel less stressed.
The researchers further found that such a “psychobiotic” diet also improved a person’s quality of sleep. We’ve all heard the old adage “you are what you eat”. Over the years, researchers have proven this to be true, showing that the foods a person chooses to eat can have a profound impact on their overall health.
Now, researchers from University College Cork in Ireland say switching to a diet rich in prebiotics and fermented foods can help reduce a person’s perceived stress levels and improve sleep quality. This study was recently published in the journal Molecular Psychiatry.
The link between diet and stress
According to Dr. John F. Cryan, Professor and Chair of the Department of Anatomy and Neuroscience and Principal Investigator of the APC Microbiome Institute at University College Cork, Ireland, and lead author of this study, the research team have been working on the relationship between stress and the gut microbiome for over 15 years, ever since they discovered that animals that were stressed early in life had an altered microbiome.
Although previous research has already 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 stress levels. This is what this study sought to do.
The microbiome is made up of an entire community of microorganisms that live in our body. This includes both beneficial bacteria and pathogenic microorganisms, which if left unchecked can harm our health. The digestive tract contains its own neural network called the enteric nervous system, which allows direct communication with the brain or the “gut-brain axis”. The gut-brain axis is critical to our ability to deal with stress. When the gut is out of balance, it impairs our ability to handle stress appropriately.
Also involved is the health of the vagus nerve known as the 10th cranial nerve which directly connects the gut to the brain. In fact, damage to the vagus nerve has been shown to directly impact digestion by slowing stomach emptying. This is also the reason why people often have gastrointestinal symptoms when under stress. Although more research is needed, consensus research has shown that there is a link between digestive tract dysfunction and stress-related conditions, such as anxiety, depression, trusted source, and down syndrome. irritable bowel.
What is a psychobiotic diet?
For this study, participants consumed foods rich in prebiotics and fermented foods. Researchers call this a “psychobiotic” diet to refer to microbiota-targeted interventions that support mental health. The psychobiotic diet was the subject of his team’s book, The Psychobiotic Revolution.
For this study, Dr Cryan and his team recruited 45 people with a relatively low fiber diet, aged between 18 and 59, in the Cork region. The researchers asked participants in the psychobiotic diet group to eat daily:
6-8 servings per day of fruits and vegetables rich in prebiotic fiber, including onions, leeks, cabbage, apples, bananas and oats
5 to 8 servings per day of cereal
2-3 servings per day of fermented foods, such as sauerkraut, kefir, or kombucha.
3-4 servings per week of legumes
Meanwhile, the researchers told the participants in the control group to eat according to the food pyramid. And participants in both groups received advice from a registered dietitian.
Reduced perceived stress
At the end of the study, the researchers found that people on the psychobiotic diet had reduced their perceived stress, or their feelings about how much stress they were currently experiencing. In addition, scientists have found that the more a person adheres to the psychobiotic diet, the more they reduce their feelings of stress.
After reviewing the study, Dr. Sepe said the psychobiotic diet includes foods that are naturally rich in prebiotics, usually foods high in fiber, which are the best food sources for beneficial gut microbes, and foods fermented foods, which are naturally rich in probiotics, the beneficial bacteria that populate our gut. These foods help promote a balanced and healthy gut microbiome, which, given the link between gut health and our stress response, can help us better manage stress.
Improved sleep quality
The researchers also found that sleep quality improved in both the psychobiotic diet group and the control group. Indeed, diet can impact sleep in several ways. For starters, the gut and its microbes are responsible for producing serotonin, the precursor to melatonin, the hormone that regulates circadian rhythm and sleep.
If we don’t produce enough serotonin due to an imbalanced gut microbiome, melatonin production will be reduced, leading to altered sleep patterns. Additionally, the gut microbiome plays a role in the production of gamma-aminobutyric acid (GABA), a neurotransmitter that promotes calm and aids sleep. Therefore, by eating a diet that supports a healthy gut microbiome, we ensure we produce enough of these crucial neurotransmitters.
Fiber or Fermented Foods: Which is Better?
For the next steps in this research, Dr. Cryan said he and his research team will try to figure out which component of the diet is more important, fiber or fermented foods.
Diet and nutrition studies are notoriously difficult to conduct, as they rely on participants’ food diaries and self-reporting, which is prone to error.
People generally have trouble sticking to diets, so it’s hard to know for sure if people are really sticking to diet parameters.
