Going with the grain: Fiber, cognition, and the microbiota-gut-brain-axis

Abstract

Healthy dietary intake has been acknowledged for decades as one of the main contributors to health. More recently, the field of nutritional psychiatry has progressed our understanding regarding the importance of nutrition in supporting mental health and cognitive function. Thereby, individual nutrients, including omega-3 fatty acids and polyphenols, have been recognized to be key drivers in this relationship. With the progress in appreciating the influence of dietary fiber on health, increasingly research is focusing on deciphering its role in brain processes. However, while the importance of dietary fiber in gastrointestinal and metabolic health is well established, leading to the development of associated health claims, the evidence is not conclusive enough to support similar claims regarding cognitive function. Albeit the increasing knowledge of the impact of dietary fiber on mental health, only a few human studies have begun to shed light onto the underexplored connection between dietary fiber and cognition. Moreover, the microbiota-gut-brain axis has emerged as a key conduit for the effects of nutrition on the brain, especially fibers, that are acted on by specific bacteria to produce a variety of health-promoting metabolites. These metabolites (including short chain fatty acids) as well as the vagus nerve, the immune system, gut hormones, or the kynurenine pathway have been proposed as underlying mechanisms of the microbiota-brain crosstalk. In this minireview, we summarize the evidence available from human studies on the association between dietary fiber intake and cognitive function. We provide an overview of potential underlying mechanisms and discuss remaining questions that need to be answered in future studies. While this field is moving at a fast pace and holds promise for future important discoveries, especially data from human cohorts are required to further our understanding and drive the development of public health recommendations regarding dietary fiber in brain health.

Microbiota and body weight control: Weight watchers within?

“…The Mediterranean, vegetarian and vegan diets include a high amount of these foods [ 378 , 379 ]. High-fibre intake has been associated with intestinal health, improved bowel motility, low risk of intestinal inflammation and colorectal cancer, low cholesterol absorption and improvement in cognitive functions [ [379] , [380] , [381] ].…”

Metabolic Syndrome, Cognitive Impairment and the Role of Diet: A Narrative Review

“…This is predominately due to the action of specific bacteria in the gut on the production of several metabolites, such as short-chain fatty acids [112], that may influence the beneficial health patterns observed in the microbiotagut-brain axis. Although there is an increased connection between dietary fiber on overall mental health, only relatively few studies have explored the connection between dietary fiber and cognition, with mixed results [113].…”

Arabinoxylans as Functional Food Ingredients: A Review

“…According to the available data, increasing daily dietary fibre intake reduces the risk of cardiovascular-related issues, diabetes, and cancer. In addition to this, emerging evidence has shown that dietary fibre consumption patterns are linked to improved mental health [ 94 , 95 ] and other cognitive functions [ 96 ]. Because of this, it is vital that a better understanding of the mechanism behind fibre’s specific health benefits is established.…”