Pinto Beans (Phaseolus vulgaris L.) Lower Non-HDL Cholesterol in Hamsters Fed a Diet Rich in Saturated Fat and Act on Genes Involved in Cholesterol Homeostasis

Abstract

Background Pinto beans contain multiple active agents such as polyphenols, flavonoids, and saponins, and have been shown to lower cholesterol, but the mechanisms involved in this effect have not been explored. Objective This study was to investigate the changes in cholesterol metabolism in response to whole pinto beans (wPB) and their hulls (hPB) supplemented into a diet rich in saturated fat and the molecular mechanisms potentially responsible for these effects in hamsters. Methods Forty-four 9-wk-old male Golden Syrian hamsters were randomly assigned to 4 diet groups (n = 11), including a 5% (wt:wt) fat diet [normal-fat diet (NF)], a 15% (wt:wt) fat diet [diet rich in saturated fat (HSF), saturated fatty acids accounted for 70% of total fatty acids], or HSF supplemented with 5% (wt:wt) wPB or 0.5% (wt:wt) hPB for 4 wk. Plasma, liver, intestinal, and fecal samples were collected to evaluate multiple cholesterol markers and gene targets. Results The plasma non-high-density lipoprotein (non-HDL) concentration was significantly reduced in the wPB- and hPB-supplemented groups by 31.9 ± 3.5% and 53.6 ± 3.2%, respectively, compared with the HSF group (P < 0.01), to concentrations comparable with the NF group. The wPB-supplemented hamsters had significantly lower liver cholesterol (45.1%, P < 0.001) and higher fecal cholesterol concentrations (94.8%, P = 0.001) than those fed the HSF. The expressions of hepatic 3-hydroxy-3-methylglutaryl CoA reductase (Hmgcr) and small intestinal acyl-coenzyme A: cholesterol acyltransferase 2 (Acat2) were significantly decreased in animals administered wPB (by 89.1% and 63.8%, respectively) and hPB (by 72.9% and 47.7%, respectively) compared with their HSF-fed counterparts (P < 0.05). The wPB normalized the expression of Acat2 to the level of the NF group. Conclusion Pinto beans remediated high cholesterol induced by HSF in male hamsters by decreasing hepatic cholesterol synthesis and intestinal cholesterol absorption, effects which were partially exerted by the hulls.

Effects of Whole Brown Bean and Its Isolated Fiber Fraction on Plasma Lipid Profile, Atherosclerosis, Gut Microbiota, and Microbiota-Dependent Metabolites in Apoe−/− Mice

“…Yeap et al [ 60 ] found that feeding diets containing fermented mung beans to hypercholesterolemic mice significantly reduced their serum levels of triglycerides, cholesterol, and LDL cholesterol. Similar cholesterol-lowering effects of pinto beans have been observed using a hamster model [ 61 ]. We observed that mice fed the bean diets had higher diet consumption and body weight gain ( Figure S2 in the Supplementary Material ), which was also inconsistent with previous findings of the weight-lowering effects of another common bean (white kidney bean) in obese mice [ 33 ].…”

“…Neither of the bean diets affected plasma lipid profile compared with the HF diet ( Figure 1 ). This was unexpected, since many animal studies suggest a hypolipidemic effect of bean foods [ 32 , 59 , 60 , 61 ]. Diet supplementation with dietary fiber from white kidney bean was reported to reduce total cholesterol in the serum of diabetic rats [ 59 ].…”

The Role of Pulses in Cardiovascular Disease Risk for Adults With Diabetes

“…123 A recent study also provides support for the role of pulse phytochemicals with their examination of whole pinto beans and a supplement of pinto bean hulls (markedly higher in total phenolic content) in a saturated fat-rich diet on cholesterol metabolism and molecular mechanisms in a hamster model. 124 Results showed that both the whole pinto beans and pinto bean hulls significantly decreased non-HDL cholesterol compared with control (by 31.9% and 53.6%, respectively) and also caused hepatic mechanistic changes, including lower liver cholesterol, higher fecal cholesterol, and higher expressions of cholesterol metabolic enzymes. 124 The glucose-lowering effects of pulses, like their lipid-lowering effects, have also been attributed to numerous pulse components including dietary fiber, resistant starch, and phytochemicals.…”

“…124 Results showed that both the whole pinto beans and pinto bean hulls significantly decreased non-HDL cholesterol compared with control (by 31.9% and 53.6%, respectively) and also caused hepatic mechanistic changes, including lower liver cholesterol, higher fecal cholesterol, and higher expressions of cholesterol metabolic enzymes. 124 The glucose-lowering effects of pulses, like their lipid-lowering effects, have also been attributed to numerous pulse components including dietary fiber, resistant starch, and phytochemicals. For example, pulse fiber has been shown to reduce postprandial glycemic response by delaying carbohydrate digestion and glucose absorption.…”

Nutritional, bioactive components and health properties of the milpa triad system seeds (corn, common bean and pumpkin)

“…Corn has a protein content of 9.3–15.8%, mainly composed of zeins and globulins ( 26 – 29 ). Common beans present a protein content of 19.1–28.3%, including albumins, phaseolins, and glutelins ( 29 – 33 ). Pumpkin seeds are rich in protein with 21.3–37.7%, mainly constituted of globulins, glutelins, and albumins ( 12 , 34 – 37 ).…”