Ingestion of Bean Leaves Reduces Metabolic Complications and Restores Intestinal Integrity in C57BL/6 Mice with Obesity Induced by a High-Fat and High-Fructose Diet.

Consumption of foods with fiber and compounds can promote gastrointestinal health and reduce obesity complications. Therefore, treatment with common bean leaves (BL) against obesity was evaluated in mice with a high-fat and high-fructose diet (HFFD) for 14 weeks. The bromatological and phytochemical characterization of BL were determined. Afterwards, the animals were supplemented with BL (10%) or a standard diet (SD) as a strategy to encourage a healthy diet for 12 additional weeks. Changes in body composition, lipid profile, and intestinal integrity were analyzed. The characterization of BL stood out for its content of 27.2% dietary fiber, total phenolics (475.04 mg/100 g), and saponins (2.2 mg/100 g). The visceral adipose tissue (VAT) decreased in the BL group by 52% compared to the HFFD group. Additionally, triglyceride levels were 23% lower in the BL consumption group compared to the HFFD group. The improvement in lipid profile was attributed to the 1.77-fold higher fecal lipid excretion in the BL consumption group compared to the HFFD group and the inhibition of pancreatic lipase by 29%. Furthermore, BL supplementation reduced the serum levels of IL-6 (4.4-fold) and FITC-dextran by 50% compared with those in the HFFD group. Metabolic endotoxemia was inhibited after BL supplementation (-33%) compared to the HFFD group. BL consumption as a treatment in obese mice reduces adipose tissue accumulation and improves the lipid profile. Furthermore, we report for the first time that BL consumption improves intestinal integrity.

Bean Leaves Ameliorate Lipotoxicity in Fatty Liver Disease.

Bioactive compounds in plant-based food have protective effects against metabolic alterations, including non-alcoholic fatty liver disease (NAFLD). Bean leaves are widely cultivated in the world and are a source of dietary fiber and polyphenols. High fat/high fructose diet animal models promote deleterious effects in adipose and non-adipose tissues (lipotoxicity), leading to obesity and its comorbidities. Short-term supplementation of bean leaves exhibited anti-diabetic, anti-hyperlipidemic, and anti-obesity effects in high-fat/high-fructose diet animal models. This study aimed to evaluate the effect of bean leaves supplementation in the prevention of lipotoxicity in NAFLD and contribute to elucidating the possible mechanism involved for a longer period of time. During thirteen weeks, male Wistar rats (n = 9/group) were fed with: (1) S: Rodent Laboratory Chow 5001® (RLC); (2) SBL: 90% RLC+ 10% dry bean leaves; (3) H: high-fat/high-fructose diet; (4) HBL: H+ 10% of dry bean leaves. Overall, a HBL diet enhanced impaired glucose tolerance and ameliorated obesity, risk factors in NAFLD development. Additionally, bean leaves exerted antioxidant (↑serum GSH) and anti-inflammatory (↓mRNA TNFα in the liver) effects, prevented hepatic fat accumulation by enhanced ↑mRNA PPARα (ß oxidation), and enhanced lipid peroxidation (↓liver MDA). These findings suggest that bean leaves ameliorated hepatic lipotoxicity derived from the consumption of a deleterious diet.

Phaseolus vulgaris L. Leaves Increase Short-Chain Fatty Acid (SCFA) Production, Ameliorating Early Metabolic Alterations.

High-fat/high-fructose diets promote early metabolic disorders in weight and lipid and glucose metabolism. Bioactive compounds such as polyphenols and fiber present in plant-based food prevent the development of metabolic disorders. The objective of the present study was to evaluate the effect of Phaseolus vulgaris L. Flor de Mayo Eugenia (FME) bean leaves on early metabolic alterations in male Wistar rats fed a high-fat/high-fructose diet. After proximate and chemical analysis of FME bean leaves, thirty-six male Wistar rats (ethical approval 06FCN2019 and 77FCN2019) were randomly assigned to one of four groups: 1) standard diet (S) fed with Rodent Laboratory Chow 5001®; 2) standard diet + 10% dry FME bean leaves (SBL); 3) high-fat (lard) and high-fructose diet (H); and 4) high-fat/high-fructose diet + 10% dry FME bean leaves (HBL). The study was carried out for six weeks. Group H exhibited early metabolic alterations compared to Group S: final weight gain (↑15%), abdominal fat accumulation (waist circumference, ↑11%), triglycerides (↑30%), glucose (↑16%), insulin resistance (HOMA-IR, ↑32%), and fecal triglycerides (↑284%) and decreased total short-chain fatty acids (SCFAs, ↓17%). FME bean leave supplementation (HBL) prevented body weight gain (↓12%), abdominal fat accumulation (waist circumference, ↓10%), and early insulin resistance (glucose area under the curve, ↓6%) compared to Group H. The supplementary bean leave diet increased SCFA production (↑54%), most likely mediated by the fiber and polyphenols present in the leaves. Therefore, bean leaves are a low-cost alternative for human nutritional care and prevention of early metabolic alterations.