Improvements in arterial stiffness due to bean and pea consumption are determined by metabolic state

Abstract

BackgroundHigher consumption of pulses (dried beans, peas, lentils, chickpeas) is associated with lower risk of cardiovascular disease due to declines in circulating LDL‐cholesterol levels and reduced blood pressure. These studies have focused on individuals who were healthy or had mild metabolic dysfunction. Furthermore, most studies have monitored cardiovascular risk factors and not vascular function directly.ObjectiveTo determine in a randomized clinical trial if metabolic disease parameters affect the response to bean and pea consumption with respect to vascular function assessed by pulse wave analysis.MethodsParticipants with mild hypercholesterolemia but not taking any cholesterol‐ or glucose‐lowering medications consumed a selection of 5 study foods containing 120 g beans or peas or rice per serving, five times per week for 6 weeks as part of their usual diet. At the Winnipeg site, vascular function was assessed non‐invasively at baseline and 6 weeks to determine arterial stiffness (augmentation index normalized to a heart rate of 75 beats per minute). The effect of body mass index, glycemia, lipidemia and blood pressure on the vascular response to beans or peas was determined by covariate analysis.ResultsNo changes in augmentation index were detected without taking metabolic parameters into account. Interestingly, arterial stiffness (lower augmentation index) was improved in persons who had consumed beans or peas, but not rice, and had levels of LDL‐cholesterol or total cholesterol above the median (3.7 mmol/L and 5.7 mmol/L, respectively) within the cohort. Lower arterial stiffness was also seen in persons consuming beans or peas and having a BMI below the median (27.5 kg/m2). Subgroup analysis also showed that insulin or triglycerides influenced augmentation index in persons consuming beans or peas, but the improvement occurred regardless of whether these values were above or below the median (53 pmol/L and 1.4 mmol/L, respectively). Metabolic factors associated with glycemia, including fasting glucose and HbA1c, were not associated with arterial stiffness.ConclusionsThis study has shown for the first time that augmentation index, a key parameter of arterial stiffness, can be influenced by several metabolic factors. Although contrary to expectations, participants with higher total and LDL‐cholesterol levels showed improvements in arterial stiffness in response to bean or pea consumption, while those with lower levels did not. In contrast, lower body mass index was associated with a reduction in arterial stiffness in persons eating beans or peas. These are the first data to indicate that the individual response of blood vessel elasticity to diet may depend upon the underlying metabolic characteristics of that individual even in the absence of overt disease.Support or Funding InformationAlberta Innovates BioSolutions and Alberta Pulse Growers