Aims: Glucose control is essential to slow disease progression in people with type 2 diabetes mellitus (T2DM). The acute effects of dry bean consumption on glucose control are well established, but their long-term effects in daily diets are less known.

Methods: The effect of daily consumption of ½ cup pinto beans, compared to ½ cup green beans, on fasting glucose, postprandial glucose and hemoglobin A1c (HbA1c) in adults with T2DM was examined. After a 2-week wash-in period, 13 participants were randomized to two 12-week long treatments: pinto beans and green beans. Before and after each intervention period, a fasted venous blood sample for glucose and HbA1c analyses was drawn. On 28 non-consecutive days, including the washin, participants kept diet records and measured capillary glucose using a glucometer 1 hour after the meal during which the treatments were consumed.

Results: Eight participants completed both treatment periods. There were no statistically significant changes (p<0.05) in fasting glucose, HbA1c or average postprandial glucose values between the two interventions.

Conclusions: Pinto beans and green beans result in comparable glycemic control when incorporated into the normal diet of adults with T2DM even though pinto beans have more available carbohydrate per serving.