A prebiotic may ease anxiety in young adults
Written by James Kingsland on May 4, 2021 — Fact checked by Anna Guildford, Ph.D.
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- There is an intimate, two-way line of communication between the gut and the brain, called the gut-brain axis.
- This allows the gut microbiota — the community of microorganisms living in the gut — to affect mood, with possible links to anxiety and depression.
- There is good evidence that prebiotics, which feed “friendly” bacteria in the gut, can help relieve depression in healthy adults.
- A new study suggests that a type of prebiotic may also reduce anxiety in some females in late adolescence, through changes in their gut microbiota.
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At first glance, the brain and the gut do not have a lot in common, but in reality, they work closely together through an exchange of hormonal, immune, and nervous signals.
The ecosystem of microorganisms that live in the human gut plays an important role in this relationship.
For example, research in mice suggests that a significant reduction in the diversity of gut bacteria, or an increased number of disease-causing species may lead to depression.
At the same time, there is some evidence that probiotics, which introduce friendly bacteria into the gut, can improve symptoms of depression.
A recent review of the research to date, reported by Medical News Today, concludes that probiotics alone or in combination with prebiotics — which feed the friendly bacteria that are already in the gut — may be effective treatments for depression.
However, the same review also notes there is insufficient evidence that these supplements have a beneficial effect on people with anxiety.
Nevertheless, some research does hint that prebiotics may help otherwise healthy people cope with stress, and that they can reduce milder forms of anxiety.
For example, a 2014 study found that a type of prebiotic supplement called galacto-oligosaccharides (GOS) reduced healthy adults’ production of the stress hormone cortisol and improved their emotional processing skills.
GOS are a type of carbohydrate that is indigestible. This means that they reach the intestine intact, where they can feed the microbiota that live there.
On the basis of the earlier study, psychologists at the University of Surrey in Guildford in the United Kingdom investigated whether GOS could be beneficial to the long-term mental health of adolescent females on the threshold of adulthood.
The transition from adolescence to adulthood is a key developmental stage for the emergence of a person’s ability to regulate emotions such as fear and anxiety.
The present research, which appears in the journal Scientific Reports, suggests that the supplement may reduce anxiety in individuals with the highest trait anxiety levels.
It also found a small but noteworthy increase in the abundance of a genus of bacteria called Bifidobacterium in the gut of those individuals, which may explain this change.
“This new research marks a significant step forward in that we were able to show that we can use a simple and safe food supplement such as prebiotics to improve both the abundance of beneficial gut bacteria in the gut and to improve mental health and well-being in young women,” says Dr. Kathrin Cohen Kadosh, senior author of the study.
GOS are found naturally in dairy products, beans, and certain root vegetables.
Medical News Today asked Dr. Cohen Kadosh whether poor diet in adolescence and young adulthood could affect anxiety levels due to its influence on the gut microbiota.
“[T]he GOS dietary supplement in our study led to an increase in beneficial gut bacteria, which in turn affected behavior and well-being. Based on this, it is plausible to suggest that a diet rich in GOS could have similar effects outside the lab; we already know that this is the case in animals.”
Dr. Cohen Kadosh added that this could be particularly important during a formative period, when behavioral patterns and the underlying brain networks develop continuously and become established.