High-fibre diets could cut blood sugar levels

Consuming high levels of fibre could help microbiota in the gut to limit blood-sugar levels, a new Rutgers University study has found.

The study divided sufferers of type 2 diabetes into two groups, with one group following an intervention diet consisting of several high-fibre foods, such as wholegrains and Chinese medicinal foods that are high in fibre and prebiotics. The control group received standard patient education and a diet of similar energy and macronutrient composition. After 12 weeks, the researchers observed a larger reduction in blood glucose levels than in the control group.

The scientists found that 89% of participants on the intervention diet achieved satisfactory glycaemic control, whereby glycated haemoglobin fell below the 7% threshold, compared to 50% from the control group.

The intervention diet also encouraged a select group of bacterial strains responsible for producing short-chain fatty acid (SCFA), which again induced better glycaemic control, in part through increased glucagon-like-peptide-1 (GLP-1) and fasting PYY peptide. These two hormones help to stimulate the production of insulin.

Rutgers University professor at the Department of Biochemistry and Microbiology Liping Zhao said: “When the fibre-promoted SCFA producers were present in greater diversity and abundance, participants had better improvement in haemoglobin A1c levels, partly via increased glucagon-like peptide-1 production.”

The study identified 141 bacterial strains as SCFA producers and found that 15 multiplied in response to the diet. Not all strains of the same species were considered ‘positive responders’ to the diet and of the 15 capable strains only five produced butyrate, which may improve insulin sensitivity in type 2 diabetes patients.

The scientists hypothesised that the findings could provide new strategies for treating type 2 diabetes and the illnesses linked to microbiota imbalance.

​“Targeted promotion of the active SCFA producers as ecosystem service providers via personalised nutrition may present a novel ecological approach for manipulating the gut microbiota to manage T2DM and potentially other dysbiosis-related diseases,” Zhao added.

“Our study lays the foundation and opens the possibility that fibres targeting this group of gut bacteria could eventually become a major part of your diet and your treatment.”

Zhao told Food Processing technology: “We recruited type 2 diabetes patients whose HbA1c was in the range of 7-10%. They have been diabetic for a few years and on medication but with no serious complications yet.”

He also stressed the importance of participant awareness in the study, saying: “Education is the key. Feedback of improvements in their glycemic control is also critical. When patients see the improvements, they are more motivated to follow the diet.”

“We need more clinical trials to find out how much you can recover the health of type 2 diabetes patients by restoring a healthy gut microbiota via a high-fibre diet.”