Substantiating a Health Claim for Pulses (Beans and Peas) and Cholesterol Lowering Abilities

OBJECTIVES: The aim of this study is to conduct a multi-centre randomized, controlled trial to compare the biological effectiveness of bean vs rice and peas vs rice (control) on LDL-cholesterol after 6 weeks in mildly hypercholesterolemic men and women. The primary outcome is LDL-cholesterol at 6 weeks, adjusted for baseline.

In addition, the effects of beans and peas on other factors associated with cardiovascular disease. Secondary outcomes are: total cholesterol, triglycerides, high density lipoprotein-cholesterol, non-HDL cholesterol, body weight, body mass index, glucose, insulin, glycated hemoglobin and biomarkers of vascular function; these are measured at 3 and 6 weeks. LDL-cholesterol at 3 weeks is also a secondary outcome. Inflammation and metabolism will be investigated. Participants' assessment of study food acceptability, satiety and gastrointestinal responses will also be collected.

BACKGROUND: Pulses (beans, peas, lentils and chickpeas) are healthy foods that contain twice the amount of protein as cereals, are very high in fibre, key vitamins and minerals like folate and iron and are low in fat. Canada is the world's largest producer and exporter of lentils and peas, and Alberta produced 34% of the pea crop and 12% of beans in 2010. Current consumption of pulses in Canada is low, due to a lack of pulse-based convenient food products. An approved health claim can drive interest in development of food products with particular ingredients as seen with oat beta-glucan. Experts agree that existing evidence for the cholesterol-lowering effects of pulses is particularly strong for beans, but more studies are needed to show the effects of peas, lentils and chickpeas are comparable to beans. Results from this study will be used to substantiate a health claim for beans and other pulse crops in the future, similar to the health claims that exist for beta-glucan and plant sterols.

METHODS AND PROCEDURES: This multi-center study will compare the effects of consuming beans (pinto, black, Great Northern, navy) to control (rice-based) and peas (yellow, green) to control (rice-based) foods for 6 weeks on Low Density Lipoprotein-Cholesterol in mildly hypercholesterolemic (>3 mmol/L and < 5mmol/L; not on medications) adults. There will be 3 study arms: i) beans, ii) peas, and iii) rice (control). The study groups will be asked to consume food items containing 120 grams of cooked beans or cooked peas daily for 6 weeks. The control group will be asked to consume 110 g of cooked, convert rice (one 3/4 cup serving per day) foods in matrices identical to those containing beans or peas for 6 weeks. The study or control foods will be incorporated into the participants normal dietary pattern. All food items will be provided to participants free of charge. Food items, generally in the form of soups or stews, will be developed by a collaborator in Food Science at the University of Manitoba in the initial phase of this project .

The investigators plan to recruit approximately 180 participants (n= 75 participants at the University of Manitoba and n= 105 at University of Alberta). Interested individuals (potential participants) will first attend a screening visit. The screening visit procedures will be discussed prior to the screening visit, including the need to fast (i.e., no food or beverage intake except water for 12 hours) for blood sampling to determine if Low-density-lipoprotein-cholesterol and triglyceride levels are within acceptable range. Once at the screening visit, individuals will be provided with a description of the study by the investigating team's study coordinator. The eligibility criteria will be reviewed with candidates by the investigating team's study coordinator to assess their suitability for the study. Individuals meeting all inclusion/exclusion criteria will be contacted by the study coordinator with this information. All individuals who are screened will be contacted by the study coordinator once eligibility has been confirmed. An appointment for a baseline assessment meeting will be scheduled for those who are eligible and who confirm interest in the study; those who are not eligible or who are eligible and no longer wish to participate will be thanked for their time.