In a new review of scientific evidence, a research team has found that foods or supplements containing microbes which are associated with positive health outcomes can also help treat symptoms of depression. These findings were published in the journal BMJ Nutrition, Prevention & Health, on Monday.
These food supplements are proven to be effective in treating many ailments of the human body. In simple terms, probiotics are beneficial bacteria, while prebiotics are food for these bacteria.
The research team from the University of Brighton and Croydon University Hospital in the United Kingdom evaluated 71 studies published between 2003 and 2019 that looked at how probiotics, prebiotics, and compounds that help probiotics flourish, can help treat depression in adults.
From all these studies, 7 were robust enough to be added to the final review and all of these studies showed significant improvement in symptoms of depression after the use of probiotics. These studies included comparison with other methods of treatment and placebos.
The scientists found that while probiotic supplements either alone or in combination with prebiotics may be linked to measurable reductions in depression, the possible contribution to lesser degree of anxiety was not clear in this review.
There were a few limitations attached to the study as well. Some of these included the limited duration of the study or the number of subjects which was very small.
These limitations can make it difficult to draw any firm conclusions about the overall effects. For example, how long the effects lasted and whether there were any unwanted side effects associated with prolonged use.
The scientists working on the study explained that though it is unknown how these food supplements help ease depression. There can be two ways in which they can work.
First, probiotics may limit the production of inflammatory chemicals, such as cytokines. These probiotics can also help direct the action of tryptophan, a chemical thought to be important in the gut-brain axis in psychiatric disorders.
The second way which was described was based on underlying factors. Depression may be caused by other underlying conditions, such as impaired insulin production and irritable bowel syndrome. In such conditions, probiotics may help reduce the severity of these underlying causes which eventually ease depression symptoms.
With new evidence coming in every day, probiotics have become more popular. As researchers learn more about gut bacteria, gastrointestinal health, and the significance of good bacteria, more and more people are consuming these products.
Research shows for those that suffer from depression, probiotics may be a worthy candidate for anyone who struggles with it.
— Lori Shemek, PhD (@LoriShemek) August 27, 2019
Previously other research has also shown how these food supplements can help relieve depression.
In 2016, a small study found that people with major depression who took a probiotic supplement for 8 weeks, had lower depression scores on the Beck Depression Inventory, a common method of evaluating depression symptoms.
In another small study, the probiotic Bifidobacterium longum NCC3001 helped with improvement of quality of life and reduce symptoms of depression in people with irritable bowel syndrome.
In a 2017 research review, scientists found that people who took a daily probiotic supplement had improvement in symptoms of both depression and anxiety.
Other research has also shown that these probiotic supplements work best when used in conjunction with other treatments, including medication and psychotherapy.
However, experts agree that more research is needed before these supplements can be used to treat depression and anxiety.
Associations between anxiety, depression and gut microbiome are clear. However, it's too early to recommend probiotics as a treatment for anxiety and depression explains Bercik #BCNMicrobiome #WorldMicrobiomeDay #GutToKnowYou pic.twitter.com/i0uAR9CTVl
— GutMicrobiota Health (@GMFHx) June 26, 2020
Depression in United States
The most common type of mental disorder in United States is the major depression.
Major depression can result in severe impairments that interfere with or limit one’s ability to carry out major life activities. According to statistics, an estimated 17.3 million adults in the United States had at least one major depressive episode in 2017 alone.
The prevalence of major depressive is also higher among adult females (8.7%) compared to males (5.3%) and the prevalence of a major depressive episode is highest among individuals aged 18-25 (13.1%).
An estimated 65% of Americans receive combined care by a health professional and medication treatment and 35% of adults with major depressive episode do not receive treatment.