Large population studies indicate that people who eat beans and soy foods at least four times a week are less likely to develop heart disease.1 It was thought that legumes had this effect due to their ability to reduce LDL cholesterol.2 However, a recent study in animals has brought a new idea to light.
A meta analysis of intervention studies on humans published this month indicates eating legumes significantly lowers blood pressure in people with high blood pressure as well as in people with normal blood pressure.3 The analysis of eight different trials found that when an average of one cup of legumes, including faba beans, lentils, chickpeas and beans, was substituted for foods of the same energy value there was a 2.25 mmHg reduction in blood pressure. A reduction of 2 mmHg is clinically relevant for lifestyle modification given that similar reductions are achieved with a low salt diet (4-5mmHg).4
A Canadian study in animals has found a new clue that may explain just how legumes are having this effect on blood pressure. The study, conducted in rats, showed that adding lentils to the diet can effectively block the increase in blood pressure that occurs with age. The findings also indicate that eating lentils can reverse the changes that occur in blood vessels as a result of high blood pressure.5
According to lead investigator Dr. Peter Zahradka, "These are amazing results, since they provide a non-pharmacological way of treating diseases associated with blood vessel dysfunction."
The investigation was undertaken after results from a clinical trial in 2013 indicated eating ½ cup a day of legumes, specifically a mixture of beans, peas, lentils and chickpeas, can improve blood flow to the legs of persons with peripheral artery disease, a condition that is closely linked to heart disease and diseases of the blood vessels.6
"The most notable finding of the latest study was the fact that lentils could alter the physical properties of blood vessels so that they resembled the vessels found in healthy animals," says
Dr. Zahradka. While human studies will still be needed to confirm these findings it does provide an interesting insight into how legumes may help prevent heart disease.
The Grains & Legumes Nutrition Council (GLNC) has commissioned the University of Wollongong to analyse data from a large Australian-based study to find out if there is a link between eating legumes and risk of heart disease in an Australian population. Results are expected later this year.
GLNC recommends Australians enjoy legumes such as lentils at least 2 - 3 times every week. Both dried and canned legumes are great additions to many meals. To reduce the salt in canned legumes, drain the canning liquid and rinse the legumes well.
For meal and snack ideas using legumes visit www.glnc.org.au
- Bazzano LA et al. Legume Consumption and Risk of Coronary Heart Disease in US Men and Women. Arch Internal Medicine. 2001;161(21):2573-8
- Bazzano LA et al. Non-soy legume consumption lowers cholesterol levels: A meta-analysis of randomized controlled trials. Nutrition, Metabolism and Cardiovascular Diseases. 2011;21(2):94-103
- Jayalath VH, et al. Effect of Dietary Pulses on Blood Pressure: A Systematic Review and Meta-analysis of Controlled Feeding Trial. American Journal of Hypertension. 2014;27(1):56-64
- Heart Foundation of Australia. Guide to management of hypertension, 2009.
- Hanson MG, Zahradka P, Taylor CG. Lentil-based diets attenuate hypertension and large-artery remodelling in spontaneously hypertensive rats. British Journal of Nutrition. DOI: http://dx.doi.org/10.1017/S0007114513002997
- Zahradka P et al. Daily non-soy legume consumption reverses vascular impairment due to peripheral artery disease. Atherosclerosis. 2013;230(2): 310–314