The smell of spicy, warm comforting red beans and bright, fluffy white rice wafts through the air. You take a bite and immediately smile as the flavors and textures blend miraculously. Forming a complete protein and supplying all nine essential amino acids, rice and beans have been a staple food for millennia Furthermore, with 13,000 varieties of beans to try, the options are endless. Originating in South America, black beans are common in Latin American and Caribbean cuisines, while chickpeas’ origins in Europe make them a common choice in Middle Eastern and Indian dishes. Black beans, chickpeas, red beans, pinto beans, lentils and many more legumes are most commonly consumed with a grain such as rice, tortillas, or potatoes [1]. Though tasty and a well-known staple, can this magical combination be deemed healthy?
Scientists have found that, for populations at higher risk of developing diseases, the promotion of traditional foods, such as legumes, can often ameliorate symptoms. As a high fiber and high protein food, legumes have particularly been reported to reduce the risk of diseases including coronary heart disease, obesity, diabetes, high cholesterol, or strokes [2]. If traditional foods like rice and legumes may improve disease risk, does eating them together offer any superior benefits over-consuming the items individually? One study regarding the consumption of rice and beans, specifically brown rice and colorectal cancer found a significant decrease in the amount of cholesterol while lowering the risk of cardiovascular disease by regulating lipid metabolism [1]. Another study contained an experimental group of individuals who were given a combination of either black beans and rice or chickpeas and rice compared to the control group of healthy women who were just given white rice. Researchers found that the experimental group experienced a significantly reduced glycemic response when compared to the control group [2]. This correlates to less insulin release, and therefore better long-term glucose control and reduction in blood lipids. Moreover, many scientists hypothesize that a lower glycemic response may contribute to a decrease in disease [3].
Additional research looked at the ability of beans to mitigate the negative effects of the high glycemic index of rice [2]. The glycemic index numerically represents how quickly the body converts carbohydrates, specifically glucose, into energy, [4]. White rice, for example, has a high glycemic index. This means that after digestion, the body rapidly releases sugar into the bloodstream, which then causes glucose and insulin levels to spike. Legumes, on the other hand, have a low glycemic index, meaning that the body slowly releases energy after consumption. Foods with low glycemic indices generally increase satiety and reduce rates of gastric emptying [2]. Specifically, legumes increase the release of two satiety hormones, GLP-1 and CCK, which may have contributed to the 31% increase in satiety self-reported by individuals in the experimental group compared to the control. Another study examined 17 participants with type II diabetes who were asked to consume either a combination of pinto beans and rice, red kidney beans and rice, or black beans and rice, and compared these findings to a control group that solely consumed rice. Researchers found that post-prandial (after meal) glucose levels were lower for the experimental group compared to the control group. As type 2 diabetes affects eight percent of the U.S. population and an even greater portion of minority individuals (11.8% of Hispanic individuals and 12.6% of African-Americans), knowledge of how to lower postprandial glucose levels may make culturally familiar foods increasingly accessible.
References:
1) Thompson, S. V., Winham, D. M., & Hutchins, A. M. (2012, April 11). Bean and rice meals reduce postprandial glycemic response in adults with type 2 diabetes: A cross-over study. Retrieved from https://nutritionj.biomedcentral.com/articles/10.1186/1475-2891-11-23
2) Winham, D. M., Hutchins, A. M., & Thompson, S. V. (2017, October 04). Glycemic Response to Black Beans and Chickpeas as Part of a Rice Meal: A Randomized Cross-Over Trial. Retrieved from https://www.mdpi.com/2072-6643/9/10/1095/htm
3) Publishing, H. H. (2020, March 25). A good guide to good carbs: The glycemic index. Retrieved from https://www.health.harvard.edu/healthbeat/a-good-guide-to-goodcarbs-the-glycemic-index
4) Beans and Grains: The Perfect Pairing. (2014, December). Retrieved from https://www.todaysdietitian.com/newarchives/120914p36.shtml
5) Glycemic Response. (2016, January 26). Retrieved from https://caloriecontrol.org/glycemic-response/
6) Bazzano LA;He J;Ogden LG;Loria C;Vupputuri S;Myers L;Whelton PK; “Legume Consumption and Risk of Coronary Heart Disease in US Men and Women: NHANES I Epidemiologic Follow-up Study.” Archives of Internal Medicine, U.S. National Library of Medicine, pubmed.ncbi.nlm.nih.gov/11718588