Impact of Diet Containing Grape Pomace on Growth Performance and Blood Lipid Profile of Young Rats.

Grape pomace (GP), the residue of grapes after wine making, is rich in dietary polyphenols and fiber, and it has potential to serve as a functional food ingredient to improve health. However, high polyphenol diets have also been reported to inhibit the growth of young animals and cause liver necrosis. This study investigated the effect of diets containing different amounts of GP on the growth performance and blood lipid profile by using a young rat model. Twenty female Sprague-Dawley rats of age 7 weeks were randomly divided into four groups that were fed AIN-93G diets that were modified by substituting 0%, 10%, 20%, and 30% of carbohydrate with GP for 10 weeks (the diets, thus, obtained contained 0%, 6.9%, 13.8%, and 20.7% of GP). The group fed original AIN-93G (0% GP) was used as control. Feed consumption, body weight, length, and height were recorded weekly. Blood samples were taken biweekly to analyze plasma lipid profile. At the end of the feeding period, the rats were fasted overnight and euthanized by exsanguination under anesthesia. Livers, hearts, and kidneys were collected, and their weights were recorded. Results show that the diet containing a maximum of 20.7% of GP did not influence the body weights, lengths, and heights of rats. As the GP content increased, the blood triglyceride and very low-density lipoproteins (VLDL) decreased, the high-density lipoprotein (HDL) and low-density lipoprotein (LDL) increased slightly but were statistically significant, and total cholesterol remained constant. In conclusion, GP in the AIN-93G diet did not influence the growth performance of young rats, but it exhibited both positive and negative effects on the blood lipid profile.

Bioavailability of polyphenols from peanut skin extract associated with plasma lipid lowering function.

Peanut skin is a rich source of polyphenols including procyanidins and is shown to have hypolipidemic properties. This study investigated the bioavailability of peanut skin polyphenols using a rat model. First, the bioavailability of peanut skin polyphenols in rat plasma was evaluated. Our results showed procyanidin A2 levels in plasma peaked within 30 min of ingestion. The results of a second study show that peanut skin extract supplemented in addition to oil gavage resulted in significant decrease in plasma triglyceride and VLDL within 5h. In the third study, rats were given a Western type diet for 5 weeks with peanut skin extract at a dose of 150 and 300 mg/kg body weight. The main effects observed were lowering of total blood lipid and reduction of the plasma fatty acids profile. Our results suggest that procyanidin A may impart a key role of hypolipidemic effect seen in peanut skin polyphenols.