When dealing with stress and anxiety, the conventional approach often involves recommending increased physical activity or practicing relaxation techniques. While these methods are indeed effective, making dietary changes can also prove to be highly beneficial. Recent research has revealed the impact of a specific diet known as the “psychobiotic diet” in reducing stress and anxiety.
In addition to probiotics and prebiotics, there are lesser-known components called psychobiotics. These are foods that positively influence the psyche by affecting the gut microbiome.
A study conducted by APC Microbiome Ireland, a group of dedicated scientists in Ireland focusing on gut microbiome research, demonstrated the stress-reducing effects of psychobiotic nutrition. The findings, published in the journal Molecular Psychiatry, indicated that incorporating psychobiotics into one’s diet could enhance resistance to stress.
In summary, not only are physical activity and relaxation techniques helpful in managing stress, but dietary adjustments that include psychobiotics can also play a significant role in reducing anxiety and promoting overall well-being.
Influence of diet on mental health
According to one of the authors, John Cryan, who wrote in The Conversation, there has been a significant body of research over the past decade highlighting the substantial impact of nutrition on our mental health. In fact, adopting a healthy diet can significantly reduce the risk of developing various common mental illnesses.
Although the precise mechanisms of how food affects the psyche are not fully understood, one potential explanation lies in the connection between the brain and the intestinal flora. This communication occurs through what is known as the gut-brain axis, which comprises the central nervous system, the neuroendocrine and neuroimmune systems, the hypothalamic-pituitary-adrenal axis, the sympathetic and parasympathetic arms of the autonomic nervous system, the enteric nervous system, the vagus nerve, and the gut microbiota.
Interestingly, the areas of the brain responsible for emotions and cognitive abilities maintain close contact with the digestive system through this intricate gut-brain axis. This connection underscores the significance of the gut microbiome and its potential influence on mental well-being and cognitive function. However, while these connections are recognized, the specific details of how they work together are still being investigated.
Relationship between gut microbiota and stress
Prior research has suggested a connection between stress, behavior, and the state of the gut microbiota, but it remained unclear whether dietary changes could effectively impact stress levels.
Addressing this question, John Cryan and his team embarked on a study with 45 healthy participants, ranging in age from 18 to 59, who had previously been following a relatively low-fiber diet.
The researchers divided the participants into two groups. One group was provided with a “psychobiotic diet” designed by nutritionist Kirsten Berding, which included foods known to promote better mental health, specifically prebiotics and fermented foods. The study spanned four weeks, during which the effects of the psychobiotic diet on the participants’ stress levels were observed.
By conducting this study, the researchers aimed to explore the potential link between dietary interventions and their impact on stress, shedding light on the role of psychobiotic foods in promoting mental well-being.
What is the psychobiotic diet?
Dr. Berding’s psychobiotic diet comprises daily intake of the following:
- 6 to 8 servings of fruits and vegetables that are rich in prebiotic fiber, such as onions, leeks, cabbage, apples, or bananas.
- 5 to 8 servings of whole grains.
- 2 to 3 daily servings of fermented foods, including options like sauerkraut, kefir, kombucha, or kimchi.
- 1 to 2 servings of legumes per day, which should include soybeans and their derivatives, specially adapted for an ovo-lacto-vegetarian diet.
In contrast, the control group received general nutrition advice and was encouraged to follow the standard guidelines for a healthy omnivorous diet.
What is the size of the servings?
In the Irish study, the recommended portion sizes for various food groups were as follows:
- Whole grain cereal: One serving could be equivalent to 1 slice of whole wheat bread, ½ cup of unsweetened muesli, or 1 cup (200ml) of cooked brown rice or whole wheat pasta.
- Fruits and vegetables: One serving might consist of 1 apple, 10 grapes, 5 strawberries, two tangerines, a bowl of lettuce, or ½ cup of cooked vegetables.
- Fermented foods: For liquid-based fermented foods, one serving was considered as 200 ml, while for solid options like sauerkraut or similar, it was 1 cup (200 g).
- Legumes: A serving of legumes was defined as ½ cup (200 ml) in cooked form.
It’s essential to note that these portion sizes were used specifically in the context of the Irish study and may vary in other countries or dietary guidelines.
Psychobiotic nutrition against stress
After the 4-week study, participants following the psychobiotic diet reported experiencing lower levels of stress compared to those in the other group. Remarkably, the degree to which they adhered to the psychobiotic nutrition guidelines correlated with a reduction in stress levels.
Both groups showed an improvement in sleep quality, but the psychobiotic eating group demonstrated more significant benefits. This observation aligns with previous research indicating the involvement of the gut microbiota in the sleep process.
The psychobiotic diet led to slight modifications in the composition of the gut microbiota. Specifically, it resulted in notable increases in the levels of certain substances, such as short-chain fatty acids and tryptophan, which are produced by gut bacteria.
These substances have strong links to mental health, which could explain why individuals consuming psychobiotics experienced reduced stress and better sleep quality.
The findings highlight the potential role of psychobiotics in positively influencing mental well-being through gut-brain interactions.
