Review explores gut-brain axis for sleep and metabolic health

Sponsored by ADS Vitality, a Netherlands-based clinical nutrition practice focused on improving metabolic health through diet, the research set out to explore the interplay between the gut microbial ecosystem and the sleep regulation pathways in the brain as crucial to the association between sleep disorders and metabolic syndrome (MetS). 

"Beneath the surface of this captivating connection, many pages remain unturned, especially one of the main mediators in this struggle: the diet," the researchers wrote. "Dietary patterns [have been] linked to the inauguration of chronic disruptions of the circadian cycle and alterations rewiring the gut microbiome."

Noting the need to further the understanding of the biological mechanisms behind this complex interacting network of neuroendocrine, immune and metabolic pathways, the systematic review aimed to describe common microbial features to improve sleep homeostasis and reduce metabolic syndrome in support of personalized dietary interventions.

Gut microbiota and sleep regulation​

Sleep disruptions are increasingly more common in today's society, with healthy sleep habits influenced by modern lifestyle factors such as shift work, nocturnal light and noise exposure, fast food, medication and social events, the researchers noted.

Chronic lack of sleep can lead to variety of health problems, including panic attacks, anxiety and depression as well as  cardiovascular disorders and an increased risk of developing diabetes and metabolic disorders. 

They noted that in this complex scenario, the role of the gut–brain axis as the main communicating pathway between gut microbiota and sleep regulation pathways in the brain reveals some common host–microbial biomarkers in both sleep disturbances and MetS.

“Over recent decades, a growing body of evidence has emerged linking the composition of the gut microbiota to sleep regulation,” the researchers wrote. “Interestingly, the prevalence of sleep disorders is commonly related to cardiometabolic comorbidities such as diabetes, impaired lipid metabolism and metabolic syndrome (MetS)."

Dietary interventions​

For their review, the researchers conducted a search of the PubMed database and identified a selection of 36 studies, both observational and randomized clinical trials exploring the gut microbial composition in both MetS and sleep disorders among adults over the last decade.

“We observed a potential common microbial signature correlating with sleep disturbances in both healthy and unhealthy subjects, mainly pointing out the detrimental role of lower abundances of butyrate producers, especially Faecalibacterium​, as well as an enrichment in the Bacteroidetes phylum​,” they reported. “A similar pattern of the decrease in short-chain fatty acid producers has been repeatedly observed in multiple cohorts of MetS.”

Tailored dietary interventions can play a role in modifying metabolic homeostasis, they suggested, which may mitigate sleep problems and improve the insulin resistance pathway that occurs in MetS.

For instance, supplementing with fibers such as “inulin in pre-diabetic subjects, arabinose-xylooligosaccharides (AXOSs) in overweight subjects, or enriched-fiber foods like whole-grain and barley bread in healthy people [could] restore cholesterol levels and microbial dysbiosis in patients with metabolic syndrome,” the researchers wrote.

As another example, following the Mediterranean diet (MedDiet) can mean a greater abundance of the Lachnospiraceae​ family. This diet can also have beneficial effects on cardiometabolic health, including on insulin and glucose levels, the researchers suggested.

Although there is not a direct correlation showing the effects of the MedDiet on sleep quality, other studies have demonstrated its positive effect on sleep disorders.

“A cross-sectional study on a large cohort of obese subjects from the PREDIMED-plus trial positively associated adequate sleep duration with beneficial effects on weight loss, BMI and waist circumference with the MedDiet coupled with physical activity,” the researchers noted.

Understanding the connections between dietary patterns and the gut-brain axis may lead scientists to better ways to handle sleep and metabolic health.  

“Determining the components of the gut microbiome that interact with this axis could be crucial for the design of tailored interventional approaches," the researchers wrote. "Personalized nutritional interventions targeting this metabolic pathway could indeed add great value to the study of associated gut microbial changes."

Source: Nutrients​
doi: 10.3390/nu16030390​
“The Microbiota–Gut–Brain Axis in Metabolic Syndrome and Sleep Disorders: A Systematic Review”
Authors: A. Santos, S. Galiè