A bean efficacy study: A dose response study to investigate the cholesterol-lowering effects of beans

Project Title:A bean efficacy study:  A dose response study to investigate the cholesterol-lowering effects of beans
Principal Investigator:Alison Duncan, University of Guelph
Co-Investigators:Dan Ramdath, Agriculture and Agri-Food Canada and Thomas Wolever, INQUIS Clinical Research Ltd (formerly Glycemic Index Laboratories)

Objectives of the study are to:

  1. To determine the effect of multiple dosages whole mixed beans on fasting serum lipid profiles (total cholesterol, LDL cholesterol (primary outcome), HDL cholesterol, triglycerides, cholesterol ratios) and apolipoproteins (apolipoprotein B, apolipoprotein AI) in hypercholesterolemic adults.
  2. To determine the effect of multiiple dosages of whole mixed beans on on fasting serum and fecal short chain fatty acid (SCFA) profiles and fecal bile acids in hypercholesterolemic adults.
  3. To determine the effect of multiple dosages of whole mixed beans on the gut microbiota in hypercholesterolemic adults.

Beans are very nutrient-dense with high amounts of dietary fibre, protein, vitamins and minerals, and low amounts of fat along with a low glycemic index. It then makes sense that people who consume beans have better nutrient intakes and overall diet quality than those who do not consume beans. Consuming beans has also been linked with lower risk of many diseases including heart disease. Studies have shown that beans can improve markers of heart disease risk such as LDL cholesterol and total cholesterol, which are among the most established markers of heart disease risk and therefore often a target for medical nutrition therapy. In fact, the most recent recommendations from the Canadian Cardiovascular Society recommend a dietary pattern high in legumes (which includes beans) for the management of high blood cholesterol to prevent heart disease.

Despite this information, bean consumption is low and there is interest in advancing ideas to change this. Health claims on bean products would provide an opportunity to communicate the benefits of beans to the consumer at the time that they are grocery shopping and would help to improve awareness of the health benefits of beans and increase the likelihood of bean consumption. However, before health claims can be approved, there is a need for more evidence, especially related to how much beans are needed to improve blood cholesterol and how beans actually improve blood cholesterol.

This research will provide that evidence by first examining two serving levels of beans and second by including measurements that would help understand how beans lower cholesterol. This research will involve a high-quality human clinical trial conducted at two sites (Guelph and Toronto) in which 60 adults who have high blood LDL-cholesterol will consume three treatments for 4 weeks each separated by a 4-week break. The treatments will include 1 cup of canned mixed beans, ½ cup of canned mixed beans and a white rice control. Blood and fecal samples will be collected before and after each treatment for analysis of blood cholesterol profile and measures that could help understand mechanisms such as bile acids, short chain fatty acids and gut bacteria. Results of this research will generate needed evidence to help the approval process of a health claim that can be included on bean products to inform consumers about the health effects of beans.