Does eating oat β-glucan–enriched bread prevent T2D in adults?

Regular oat-derived β-glucan–enriched breads do not provide metabolic benefits to adults at risk of type 2 diabetes (T2D) in real-life settings, as shown by a recent study.

"A simple bread replacement may not be sufficient to improve glucose homeostasis in individuals at risk of T2D,” the investigators said. 

A randomized, double-blind dietary intervention was conducted for 16 weeks in 194 adults (mean age 58 years, BMI 32 kg/m²; HbA1c 5.6 percent; LDL cholesterol 3.5 mmol/L) across sites in Germany, Norway, and Sweden. Participants consumed ≥3 slices/day of either β-glucan–enriched bread (6 g β-glucan/day) or control bread for 6 days/week.

At week 16, the investigators did not observe any significant difference in HbA1c (Δ, –0.01 percent, 95 percent confidence interval [CI], –0.03 to 0.06; p=0.49) between groups. 

Likewise, no between-group differences were noted in fasting glucose (Δ, –0.02 mmol/L, 95 percent CI, –0.11 to 0.14), insulin (Δ, –0.76 pmol/L, 95 percent CI, –0.99 to 2.5), or LDL cholesterol (Δ, –0.11 mmol/L, 95 percent CI, –0.27 to 0.05; p>0.05 for all).

“A high intake of whole grains is associated with reduced risk of T2D and cardiovascular disease, and soluble fibre from oats and barley, that is, β-glucans, has been shown to lower blood cholesterol and postprandial glycaemia,” the investigators said. 

“Despite such data and the European Food Safety Authority health claims supporting β-glucan–induced reductions in glucose and cholesterol, effectiveness in real-life settings among individuals at elevated risk of developing T2D remains unclear,” they added.