The review suggests regulating the gut microbiome and altering your diet to reduce anxiety could be effective approaches to gut health and anxiety.
A team of researchers has reviewed literature covering 1503 people and determined that regulation of the intestinal microbiota could have a positive effect on anxiety.
Symptoms of anxiety are common in those with mental and some physical disorders, with up to a third of people suffering symptoms in their lifetime. Research has indicated that the gut microbiome can affect brain function through the ‘gut–brain axis’; however, it has remained inconclusive whether regulating the gut can help mental disorders.
The team, from the Shanghai Mental Health Center at Shanghai Jiao Tong University School of Medicine (China), reviewed 21 studies, of which 14 used probiotic “good bacteria” interventions and seven non-probiotic interventions such as diet regulation.
Of the 21 studies, 11 showed a positive effect on symptoms of anxiety. Of the 14 using probiotics, 36% found them to be effective, while six of the seven non-probiotic studies showed an effect (86%). Of five studies that used both interventions and normal treatment, only those that used non-probiotic interventions reduced anxiety symptoms.
The authors believe that the increased efficacy from non-probiotic interventions might be due to the higher impact of diet change compared with probiotic supplementation. The authors postulated that this might be due to diet change resulting in a significant difference in energy supply for the bacteria, the period of the interventions being too short to have a significant effect, or the wide range of species used resulting in some not being effectively implanted.
Of the studies, only four reported mild adverse effects (such as dry mouth and diarrhea), and none reported serious adverse events.
While the study suffered limitations owing to its observational nature and differences in design of the included studies, the authors are hopeful that further research will be carried out and confirm once and for all whether altering the intestinal flora can improve anxiety.