Gut microbes may mediate sugar-sweetened beverage impact on diabetes risk

Scientists have expanded knowledge of the gut microbiome’s impact on digestion and overall health. New research examines microbes’ role in mediating the link between sugary beverage consumption and diabetes risk.

Researchers identified differences in the gut microbiota and blood metabolites of people with high sugar-sweetened beverage consumption in a long-term study with US Hispanic and Latino adults. They linked this altered metabolite profile to a higher risk of developing diabetes in the next ten years. 

“Our study suggests a potential mechanism to explain why sugar-sweetened beverages are bad for your metabolism,” says senior author Qibin Qi, an epidemiologist at the Albert Einstein College of Medicine, US. “Although our findings are observational, they provide insights for potential diabetes prevention or management strategies using the gut microbiome.”

Previous research demonstrated that sugar-sweetened beverages alter the gut microbiome composition. However, according to the US research team, this is the first study to analyze whether microbial changes impact host metabolism and diabetes risk. 

The study is also the first to research the issue in US-based Hispanic and Latino populations. The researchers say this population group experiences high diabetes rates and consumes high volumes of sugar-sweetened beverages. 

Gut microbiome composition

For the study published in Cell Metabolism, the researchers used data from an ongoing large-scale cohort study with data from over 16,000 participants. 

At baseline, researchers asked participants to recall their diet from the past 24 hours and drew blood to characterize their serum metabolites. 

The team also collected fecal samples and characterized the gut microbiome of 3,035 participants in a follow-up visit. They used these data to identify the association between beverage intake, gut microbiome composition, and serum metabolites. 

High sugar-sweetened beverage intake, over two drinks daily, was associated with changes in the abundance of nine bacterial species. Four of these species produce short-chain fatty acids (SCFA), molecules known to impact glucose metabolism positively. SCFA are created when bacteria digest fiber. 

According to the researchers, bacterial species positively associated with sugary beverage intake correlated with worse metabolic traits. These bacteria were not associated with sugar from non-beverage sources. 

Other research suggests gut bacterium Bacteroides vulgatus influences sugar cravings through a metabolic pathway involving a free fatty acid receptor. The study notes that restoring B. vulgatus levels may help regulate sugar intake and glucose metabolism.

Participants with higher levels of specific serum metabolites were more likely to develop diabetes in the ten years after their initial visit.Modulating microbial metabolites

The team found associations between the intake of sugary beverages and 56 serum metabolites, including those produced by the gut microbiota or derivatives of other metabolites produced by the gut. 

They linked these metabolites with worse metabolic traits, such as higher fasting blood glucose and insulin levels, higher body mass index and waist-to-hip ratios, and lower ratios of high-density lipoprotein or “good” cholesterol. 

According to Qi, these “metabolites may predict future diabetes.” Participants with higher levels of these metabolites were more likely to develop diabetes in the ten years after their initial visit. 

However, since the team collected gut microbiome samples from a subset of participants, there was an insufficient sample size to determine if any specific microbes were directly associated with diabetes risk. 

“In the future, we want to test whether the bacteria and metabolites can mediate or at least partially mediate the association between sugar-sweetened beverages and the risk of diabetes,” says Qi. 

The researchers also aim to validate their findings in other populations and extend the analysis to determine if microbial metabolites are involved in different health issues linked to sugar consumption, such as cardiovascular disease. 

Sugar-sweetened beverages intake

In 2017 and 2018, US adults consumed an average of 34.8 grams of added sugar daily through sugar-sweetened beverages such as soda and fruit juice. These drinks are the main source of added sugar in US adults’ diets. 

Qi says that compared to added sugars in solid foods, sugars in beverages might be more easily absorbed and have a high energy density “because they’re just sugar and water.” 

Last month, researchers estimated that sugar-sweetened beverages were linked to 2.2 million new cases of type 2 diabetes and 1.2 million new cardiovascular disease cases worldwide in 2020. 

Meanwhile, research indicates that the UK’s soft drink levy has significantly reduced sugar consumption. Drinks alone reduced daily added sugar consumption by 3 grams in children and 5.2 grams in adults. This policy, implemented in 2018, adds a higher levy to drinks with a higher sugar content.