Chlorogenic acid (5-O-caffeoyl-quinic acid; CGA) is an important constituent of coffee so consumed regularly in the human diet. CGA intake has been associated with decreased risk of cardiovascular disease and type 2 diabetes. This study investigated whether CGA improves cardiovascular, liver and metabolic responses in a diet-induced rat model of metabolic syndrome induced by a high-carbohydrate, high-fat diet. This diet causes central obesity, impaired glucose tolerance, dyslipidaemia, cardiovascular remodelling, non-alcoholic fatty liver disease and tissue inflammation.
Male Wistar rats (8-9 week old, 335 ± 5 g, n = 48) were divided into 4 groups and fed with either corn starch diet (16 weeks), corn starch diet with ≈180 mg/kg/day CGA in food for last 8 weeks, high-carbohydrate, high-fat diet (16 weeks) or high-carbohydrate, high-fat diet with ≈100 mg/kg/day CGA in food for last 8 weeks. Rats were evaluated for metabolic, cardiovascular and liver structure and function at the end of protocol.
In high-carbohydrate, high-fat diet-fed rats, CGA reduced energy intake and food efficiency to reduce visceral fat (especially retroperitoneal fat pads) and abdominal circumference compared to their obese control rats. In these obese rats, CGA reversed the elevated systolic blood pressure and attenuated left ventricular diastolic stiffness while reducing collagen deposition and infiltration of inflammatory cells in the left ventricle. CGA also decreased inflammation and fat deposition in the liver, and plasma liver enzyme activities of obese rats. However, CGA did not change the plasma lipid profile.
These results suggest that the decreased risk following CGA consumption is related to the decreased inflammation associated with high-carbohydrate, high-fat diets.