Study reveals how a gut microbe helps break down sugars

European researchers have published a complete systematic analysis of how the microbe Akkermansia muciniphila (AM) feeds on sugars locked away in mucus secreted in the digestive system. As the microbe protects the gut barrier from harmful pathogens, it is included in biotics to support gut health. 

The study focused on 66 enzymes that AM uses to break down O-glycans (sugars), which comprise around 80% of gel-forming secreted mucins or glycoproteins in the mucus lining the human large intestine. This layer is a barrier between host cells and microorganisms in the colon. 

Although an estimated 60% of human gut microbiota can access mucin as a nutrient source, the researchers say this process and its links to disease are not fully understood. 

“This is the first time we have comprehensively seen how microbes break down the food source O-linked sugars in the gut. This is the first time that a set of enzymes has been used to completely break down the glycan part of mucin,” says co-author Dr. Lucy Crouch, Sir Henry Dale Fellow at the University of Birmingham, UK. 

“These newly characterized enzymes may be used in characterizing the different glycans that humans produce, which can indicate disease.”

Immunity benefits

Under healthy conditions, mucin is produced and broken down in a balanced manner, but disease states are linked to a disrupted mucosal layer and changes in bacteria proportions. Research indicates that AM prevalence decreases proportionally to disease and inflammation markers. 

Using mucus from a pig model, the researchers determined that a combination of enzymes from AM could completely break down the mucin. They say that the study, published in Nature Microbiology, is the first comprehensive understanding of the molecular mechanisms behind a microbe breaking down O-glycans. 

The researchers determined that AM enzymes could completely break down the O-glycans in the gut’s mucus.“These glycans, and others like them, are receptors for various pathogens and their toxins, such as Shiga toxin. So, if we can modify the glycans, we may be able to change the severity of disease,” says Crouch. 

“AM proteins and outer membrane extracts of AM have been shown to exert positive effects on the host, e.g., a positive effect on metabolism. Some of these proteins interact with host receptors to likely suppress an immune response. AM is relatively close to the host as it wants the mucus we produce, so we probably interact with it in many different ways.”

Biotic developments

The abundance of Akkermansia species is linked to a stable and diverse gut microbiome. Research indicates that Akkermansia species tends to decline in older adults, which is associated with poorer health outcomes. 

Last year, biotech companies Pendulum Therapeutics and BiomeSense conducted a 14-week study to explore the AM strain, which they say makes up around 4% of intestinal bacteria. 

“We know that AM is a hugely important microbe, and levels of the microbe can be a good indicator of overall health,” highlights Crouch. 

“The bacteria are always beneficial for the gut, and lower levels are associated with inflammatory diseases and diabetes. AM is hugely sensitive to decreasing levels of fiber in the diet, too.”

Meanwhile, the nutrition industry includes Akkermansia bacterial strains in probiotics for gut and metabolic health while also developing specific prebiotics to increase Akkermansia bacteria in the gut. The Akkermansia Company received a US patent for its Akkermansia probiotic to support metabolic disorders, particularly obesity. 

Research shows that Nexira’s VinOgrape plus natural grape extract enriches the gut in AM. Speaking to Nutrition Insight, the company highlighted AM’s beneficial role in addressing metabolic disorders. Nexira referred to research linking the beneficial bacteria to reduced fat mass and inflammation.