Effect of feeding grape pomace on selected metabolic parameters associated with high fructose feeding in growing Sprague-Dawley rats.

The effect of feeding grape pomace on certain metabolic parameters associated with high fructose (HF) feeding was studied. Forty male growing Sprague-Dawley rats were randomly assigned into groups: (1) control; (2) HF; (3) HF with low-level (1.5% of diet) grape pomace (HF+LP), and (4) HF with high-level (5.0% of diet) grape pomace (HF+HP). The HF+LP and HF+HP diets provided 115 and 218 mg of procyanidins/kg, respectively. Compared with the controls, HF-fed animals consumed less and were smaller, whereas animals in the HF+LP and HF+HP groups were in between. A similar trend was observed for abdominal fat and abdominal fat as a percentage of body weight. No change in heart or kidney weight occurred. Liver weight as a percentage of body weight was higher for animals when fructose was included in the diet compared with those on control diet, and inclusion of grape pomace had no effect. Fasting plasma glucose, insulin, and triglyceride levels tended to be higher in animals fed HF diet, and grape pomace reduced their levels to values similar to the control animals. Compared with control animals, HF-fed animals had higher weekly postprandial plasma triglycerides, which were reduced by feeding grape pomace, but no change in plasma cholesterol was observed. Glucose intolerance was observed in animals fed HF diet and was accompanied by a 25% increase in homeostatic model assessment (HOMA) of insulin resistance. Inclusion of grape pomace increased glucose tolerance and insulin sensitivity. No significant change (P>.1) in HOMA of β-cell function or Quantitative Insulin-Sensitivity Check Index was observed. Overall, HF diet did not produce as strong a response of metabolic syndrome as has been shown in the literature. The inclusion of grape pomace in the diet was effective in modulating some aspects of metabolic parameters associated with metabolic syndrome, and the higher level of grape pomace in the diet produced a slightly better response than the lower level.