Molecular weight affects oat β-glucan dose needed to impact glycaemic response in nondiabetics

Molecular weight (MW) appears to be an important factor in determining the required dose of oat β-glucan (OBG) to elicit a significant reduction in mean glucose peak among healthy people without diabetes, a recent meta-regression has found.

Drawing from the online repositories of Medline, Embase, and the Cochrane library, the researchers retrieved acute, crossover, and single-meal feeding trials that assessed the impact of adding OBG or oat bran to a carbohydrate-containing test-meal. The primary outcome was glucose incremental area under the curve (iAUC).

Meta-regression analysis revealed that the minimum dose of OBG to induce glycaemic response (MinDose) at the 120-minute follow-up was 3.2 g for low-MW OBG. This dropped to 2.2 and 0.2 g for medium- and high-MW OBG, respectively. In calculating these MinDoses, the researchers also used a comparator control test-meal, which contained an equivalent amount (30 g) of available-carbohydrates.

The same was true for longer follow-ups, such that MinDoses required to affect glucose iAUC increased with lower MWs of OBG.

Similarly, MinDoses associated with a 10-percent, 15-percent, and 20-percent reduction in glucose iAUC were 1.4, 2.1, and 2.8 g, respectively, for high-MW OBG. In contrast, such values could not be determined for medium- and low-MW OBG.

“More high-quality trials are needed to determine the MinDose for insulin responses and MinDose for glucose and insulin responses in [patients] with T2D,” the researchers said.