Dietary Fiber and Glycemic Control in T2D: Is There a Link?

The following article is part of coverage from the American Diabetes Association’s 80th Scientific Sessions (ADA 2020). Because of concerns regarding the coronavirus disease 2019 (COVID-19) pandemic, all ADA 2020 sessions and presentations were transitioned to a virtual format. While live events will not proceed as planned, readers can click here to view more news related to research presented during the ADA 2020 virtual experience.

Increased dietary fiber intake from either a high-fiber diet or supplementation plays little role in improving glycemic control in type 2 diabetes (T2D), according to study results presented during the American Diabetes Association’s 80th Scientific Sessions, held online from June 12 to 16, 2020.

Researchers conducted a 12-week, randomized, open-label, comparator-controlled study to examine the effects dietary fiber on glycemic control in 72 patients with T2D. All patients were overweight and received metformin therapy.

The participants were randomly assigned 1:2:1 to an intensive nutrition program including a high-fiber diet, dietary fiber supplements, or standard diet. Dieticians reinforced dietary recommendations in all 3 groups on a monthly basis. The study groups were similar with regard to age, body mass index, metformin intake, hemoglobin A1c (HbA1c), and initial fiber and calorie intake at baseline.

Biochemical and anthropometric measurements taken at baseline and 12 weeks displayed significant improvements in HbA1c and body weight in all 3 groups, with no between-group differences in the magnitude of changes. Mean HbA1c decreased from 7.1%±0.5% to 6.6%±0.6% in the high-fiber diet group, from 7.1%±0.5% to 6.8%±0.5% in the fiber supplement group, and from 7.2%±0.4% to 6.7%±0.5% in the group that followed standard diet recommendations (P <.001 for all), and mean body weight decreased by 2.1±2.6 (P <.0001), 1.0±1.8 (P <.05), and 1.1±2.1 kg (P <.05), respectively.

Compared with the standard diet group, dietary fiber intake increased significantly in the high-fiber diet and fiber supplementation groups, but was not found to be associated with HbA1c. Calorie intake, however, was significantly associated with reductions in HbA1c in all 3 groups (r =0.307; P <.01).

“[O]ur study suggested that rather than fiber intake, caloric restriction followed by moderate weight loss is the main driver for glycemic improvement in overweight patients with T2D,” concluded the investigators.

Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.

Reference

Tramontana F, Maddaloni E, Greci S, et al. The effect of dietary fiber in combination with metformin therapy in type 2 diabetes. Presented at: American Diabetes Association 80th Scientific Sessions; June 12-16, 2020. Abstract 227-OR.

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