Soluble fibre supplements may improve glucose control
People with type 2 diabetes who take soluble fibre supplements have slightly lower blood sugar than their peers who don't add this type of fibre to their diets, a research review has found.
Researchers focused on supplements containing viscous fibre — a type of soluble fibre that forms a thick gel when mixed with water.
Foods such as legumes, asparagus, oats and flax contain viscous fibre; supplements with this type of fibre include guar gum, psyllium and pectin.
To examine the connection between viscous fibre supplements and blood sugar, researchers examined data from 28 clinical trials with almost 1400 participants with type 2 diabetes.
People were randomly chosen to take viscous fibre supplements, other types of supplements without viscous fibre or no supplements at all.
Most trials in the study focused on HbA1c levels.
Among the people taking viscous fibre supplements, half consumed doses above 13g daily for periods ranging from three weeks to a year.
Compared with participants who didn't take viscous fibre, those who did had lower levels of HbA1c and lower fasting glucose levels.
The results "suggest that intake of around one tablespoon of concentrated viscous fibres — such as konjac, guar, pectin or psyllium — would result in reductions in A1c and other diabetes risk factors", according to senior study author Dr Vladimir Vuksan of St Michael's Hospital and the University of Toronto in Canada.
Fibre supplements are associated with average HbA1c reductions of 0.58%, which is greater than the minimum 0.3% reduction the US Food and Drug Administration looks for in evaluating new diabetes drugs, the study authors note.
In addition to HbA1c, other markers of diabetes, including fasting glucose and insulin sensitivity, were also improved.
People with diabetes have long been advised to consume more fibre as a way to help lower their blood sugar, but many don’t get anywhere near enough fibre to make a meaningful difference in diabetes, the study authors write in Diabetes Care.
Supplements have become an increasingly common way for these patients to get more fibre.
While the reason viscous fibre seems to lower blood sugar isn't clear, scientists think that it might work in a variety of ways, including improving microbial health in the gut.
More information: Diabetes Care 2019.