Dried beans lower cholesterol and glycated hemoglobin while peas lower blood pressure in adults with mild hypercholesterolemia

Abstract

Pulses (dried beans, peas, lentils and chickpeas) are healthy foods yet are not regularly consumed in the typical North American diet. Recent meta‐analyses indicate that pulses are effective for lowering blood cholesterol and blood pressure and for glycemic control. Many of these studies have been conducted with beans and there is a relative absence of studies using dried peas. The objective of this multi‐site randomized clinical trial was to compare the effects of consuming foods containing Beans or Peas to Rice (control) on blood cholesterol, glycemia and blood pressure in men and women with mild hypercholesterolemia but not taking any cholesterol‐or glucose‐lowering medications. Participants (n=180, 20–75 years old) consumed the study foods (a selection of 5 items containing 120 g beans or peas or rice per serving) five times per week for 6 weeks as part of their usual diet; the rest of the diet was self‐selected. The study foods were provided frozen and contained either Beans (black, great northern, pinto, navy, mixture of all 4), Peas (yellow, green, mixture of both) or white Rice. Anthropometric measurements and fasting blood samples were obtained at baseline and 6 weeks. Data were analyzed by ANCOVA. Participants had a body mass index in the overweight range (~28 kg/m2), mildly elevated LDL‐cholesterol and total cholesterol (~3.8 and ~5.9 mmol/L, respectively), slightly elevated systolic blood pressure (~128/76 mmHg), but fasting glucose (~5.2 mmol/L) and glycated hemoglobin (~5.6%) within normal ranges. Consumption of the study foods for 6 weeks did not alter anthropometric measurements (body mass index, waist or hip circumference). After 6 weeks, the Beans group, but not the Peas group, had significantly lower LDL‐cholesterol (P=0.14) and total cholesterol (P=0.14) compared to the Rice group. Although fasting blood glucose and insulin were unchanged, the Beans group, but not the Peas group, had significantly lower glycated hemoglobin (P=0.05) compared to the Rice group. In contrast, systolic blood pressure was reduced (P=0.05) and there was a trend for lower diastolic pressure (P=0.097) in the Peas, but not the Beans group. In conclusion, regular consumption of pulses in amounts consistent with a food guide serving improved cardiovascular risk factors in people with mild hypercholesterolemia. However, pulse type was important as Beans lowered cholesterol and glycated hemoglobin whereas Peas lowered systolic blood pressure. The benefits for glycemia and blood pressure management were observed in individuals with normal glycated hemoglobin and blood pressure considered prehypertensive. Regular consumption of a mixture of pulses holds promise as a food‐based approach for reducing risk of cardiovascular disease and type 2 diabetes.Support or Funding InformationAlberta Innovates BioSolutions and Alberta Pulse Growers