Medically reviewed by Onikepe Adegbola, MD, PhD
Several brain disorders are related to brain-gut-microbiome interactions. Several studies have shown that the gut microbiome and brain are connected via channels. Diet affects not just the gut microbiota but also the formation and function of the brain via these communication routes.
The goal of this review is to compile information from preclinical and clinical research on the relationship between dietary habits and treatments and a variety of neurologic and psychiatric disorders. Depression, cognitive decline, Parkinson’s disease, autism spectrum disorder, and epilepsy are among these illnesses.
Psychosomatic medicine asserts that stress, emotional, and cognitive influences affect body functions.
Diet Can Have Multiple Effects On The Brain
Research from the Human Microbiome Project and early rodent studies have introduced the concept of the brain-gut-microbiome (BGM) axis.
Nutritional psychiatry has emerged as an exciting area of study in psychiatry since researchers have concluded that diet has a significant influence on the composition and function of gut microbiomes. In addition to the direct effect of macro and micronutrients on the brain, research has shown that diet could also influence gut microbiomes, thereby affecting mood and cognitive function.
The brain and gut microbiome are connected by hubs. The hubs are connected with multiple feedback loops to create a nonlinear system. Dietary components influence the brain, the gut, and the gut microbiome in different ways. Several components of the diet can directly affect the gut. They reach the brain after they are absorbed in the small intestine.
Communication Between Neurons And The Endocrine System
Metabolism of dietary components is common among microbes. Some of these metabolites have been shown to affect brain structure and function in preclinical studies
Enteroendocrine cells contain important signaling molecules, including hormones, which can act as neurotransmitters. This neuroendocrine channeling can influence your appetite and alertness.
An endocrine metabolite called indoxyl sulfate may have a role in the pathogenesis of a variety of diseases, including Alzheimer’s disease and depression.
As part of the immune-regulatory pathways, the gut microbiome is directly able to affect brain neuroinflammation via immune activation.
There is an intricate link between inflammatory signals produced in the gut in response to certain diets and the gut microbiota’s role. It ultimately generates anti-inflammatory signals. But researchers could not understand the complete mechanism between diet, the gut microbiome, and brain disease. However, scientists have found certain evidence for selective neurological and psychiatric diseases.
Diet And Pathophysiology Of Mental Disorders
In recent studies, it was shown that MDD patients have an altered gut microbiome in comparison to healthy controls.
Due to the crucial role of dietary factors in bile acid synthesis, secondary bile acids are only generated by certain gut microbes. It makes sense that dietary factors and the gut microbiome may play a role in the observed changes in the primary/secondary bile acid ratio. There is some strong evidence linking gut microbes and depression. Some of them also play a role in Alzheimer’s disease.
What Is The Biggest Challenge?
Several published studies suggest that nutritional interventions may provide therapeutic benefits in chronic brain disorders, a significant advance in an area that has not seen significant progress in the development of novel medications. Among all the challenges, the disease specificity of altered gut microbial signaling mechanisms is a major question.
There is mounting evidence that a mostly plant-based diet, high in fiber and polyphenols, is beneficial to mental health.
Through multiple mechanisms, diet and microbiota interact to affect brain structure and function throughout the lifespan.
The practical implications of specific dietary interventions remain limited until an objective therapeutic benefit is established.
Horn, J., Mayer, D. E., Chen, S., & Mayer, E. A. (2022, April 20). Role of diet and its effects on the gut microbiome in the pathophysiology of mental disorders. Nature News. Retrieved May 3, 2022, from https://www.nature.com/articles/s41398-022-01922-0