People who suffer from anxiety can reduce their symptoms by eating friendly bacteria, a new study has found.
Anxiety is estimated to affect up to five per cent of the UK population with slightly more women affected than men.
It is also more common in people from the ages of 35 to 59. It is estimated a third of people will be affected by anxiety symptoms during their lifetime.
Now a new review suggested the condition might be alleviated by regulating gut bacteria with probiotic and non-probiotic food and supplements.
The findings suggested a potentially useful link between gut microorganisms and mental disorders
The gut microbiota is trillions of microorganismswhich perform important functions in the immune system and metabolism by providing essential inflammatory mediators, nutrients and vitamins.
But previous research has shown it can help regulate brain function through something called the “gut-brain axis.”
Recent research also suggests that mental disorders could be treated by regulating the intestinal microbiota, but there is no specific evidence to support this.
So scientists from the Shanghai Mental Health Centre at Shanghai Jiao Tong University School of Medicine, investigated if there was evidence to support improvement of anxiety symptoms by regulating intestinal microbiota.
They reviewed 21 studies that had looked at 1,503 people collectively.
Of the 21 studies, 14 had chosen probiotics as interventions to regulate intestinal microbiota (IRIFs), and seven chose non-probiotic ways, such as adjusting daily diets.
Probiotics are living organisms found naturally in some foods that are also known as “good” or “friendly” bacteria because they fight against harmful bacteria and prevent them from settling in the gut.
They found probiotic supplements in seven studies contained only one kind of probiotic, two studies used a product that contained two kinds of probiotics, and the supplements used in the other five studies included at least three kinds.
Dr Jinghong Chen said: “First of all, more than half of the 21 studies included in this paper showed that regulating intestinal flora can effectively improve anxiety symptoms.
“Of the 14 studies that used probiotics as the intervention, 36 per cent of
the studies were effective, while six of the seven studies using non-probiotics as interventions were effective, and the effective rate was 86 per cent.”
Explaining why non-probiotic interventions were more effective than the probiotic interventions was possible due to the fact that changing diet (a diverse energy source) could have more of an impact on gut bacteria growth than introducing specific types of bacteria in a probiotic supplement.
Also, because some studies involved introducing different types of probiotics, these could have fought against each other to work effectively.
Many of the intervention times used might also have been too short to significantly increase the abundance of the imported bacteria.
Two thirds of the studies used probiotic intervention to regulate intestinal flora, while only a third used non-probiotic ways
Dr Chen said: “On the one hand, this indicates that more and more researchers have
realised that microflora plays an increasingly important role in human health, but on the other hand, the function of diets in daily life has been neglected by people.
“The effect of dietary structure adjustment is better than that of probiotic supplements.
“In the future, more attention can be paid to the regulation of intestinal flora through non-probiotic ways, or the combination of probiotic and non-probiotic means,
which may have unexpected effects.
“In the clinical treatment of anxiety symptoms, in addition to the use of psychiatric drugs for treatment, we can also consider regulating intestinal flora to alleviate anxiety symptoms.
“Especially for patients with somatic diseases who are not suitable for the application of psychiatric drugs for anxiety treatment, probiotic methods and/or non-probiotic ways can be applied flexibly according to clinical conditions.
“However, there are still some studies showing that the effect of regulating intestinal flora to improve anxiety symptoms is limited.
“More studies are needed to clarify this conclusion since we still cannot run meta-analysis so far.”
The review was published in the BMJ’s General Psychiatry.
