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Latest study suggests probiotic regulation can help reduce stress levels

2019-07-24 09:15 Wednesday

People who experience symptoms of anxiety may benefit from taking steps to regulate the microorganisms in their gut by using probiotic food and dietary supplements, or making other adjustments to their diet, according to a recent academic study.


Probiotics are living organisms are found naturally occurring in some foods. These are also known as "good" or "friendly" bacteria because they fight harmful bacteria and prevent them from settling in the gut where they can cause trouble.

You can commonly find probiotics in dietary supplements and as ingredients in functional foods like bio yogurt, miso extract or kombucha tea. Doctors have traditionally suggested them to patients to help with digestive problems.

Symptoms of anxiety are highly common in patients with mental illness and a variety of other physical disorders and diseases, especially those related to stress, says the study, published in the journal General Psychiatry.

Clinical health figures have shown that up to a third of people will be affected by some sort of anxiety symptoms in their lifetime.

More than ever, scientific research has indicated that gut microbiota – the extensive ecosystems of microorganisms found in the gut which perform functions necessary for the immune system and metabolism, by providing essential inflammatory mediators, nutrients and vitamins – can have a positive role in regulating brain function. This relationship is known as the "gut-brain axis."

More research has suggested that some mental disorders could be treated by regulating intestinal microbiota, but there has been no specific evidence to support this so far.

To address this question, a team from the Shanghai Mental Health Center at Shanghai Jiao Tong University School of Medicine, set out to investigate. They reviewed twenty-one studies that had looked at just over 1,500 people in total.

Of the 21 studies, fourteen had chosen probiotics as potential ways to regulate intestinal microbiota. Meanwhile, seven chose non-probiotic methods to affect gut flora, such as by adjusting daily diets.

The researchers found that probiotic supplements in 7 studies within their analysis contained only one kind of probiotic; 2 studies used a product that contained 2 kinds of probiotics, and the supplements used in the other 5 studies included at least 3 types.

Overall, eleven of the 21 studies showed a positive effect on anxiety symptoms by actively regulating intestinal microbiota, meaning that more than half (52 percent) of the studies showed this approach to be effective. On the other hand, some studies that used this approach did not find it worked.

Of the fourteen studies that had used probiotics as the intervention, more than a third (36%) found them to be effective in bringing down symptoms of anxiety, while 6 of the remaining 7 studies that had used non-probiotic methods as interventions found those to be effective – a rate of 86% effectiveness.

Non-probiotic interventions were also more effective in the studies that used interventions to regulate intestinal microbiota (IRIF) alone. In those studies only using IRIF, 80% were effective when using non-probiotic interventions, while only 45% were found to be effective when using probiotic approaches such as a supplements and functional ingredients.

Most of the studies did not report any serious adverse events from consuming probiotics, and only 4 studies reported mild adverse effects such as dry mouth or diarrhoea from participants.

The study was observational only, and as such, could not establish a definite cause. Indeed, the authors acknowledge there were some limitations to their approach, such as differences in study designs, subjects, interventions and measurements, making the data unsuitable for further analysis. Nevertheless, they say the overall quality was high for the 21 studies they looked at.

The researchers finally reported that: "We find that more than 1/2 of the studies included showed it was positive to treat anxiety symptoms by regulation of intestinal microbiota.

"There are 2 kinds of interventions (probiotic and non-probiotic interventions) to regulate intestinal microbiota, and it should be highlighted that the non-probiotic interventions were more effective than the probiotic interventions. More studies are needed to clarify this conclusion since we still cannot run meta-analysis so far."

They also suggest that, in addition to the use of regular psychiatric drugs for the healthcare treatment of patients, "we can also consider regulating intestinal flora to alleviate anxiety symptoms."

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