Alterations in carbohydrate and lipid metabolism induced by a diet rich incoconut oil and cholesterol in a rat model

Objective: The type of dietary fat as well as the amount of cholesterol occ urring in the diet have been associated with several metabolic disorders. T hus, the aim of the present study was to investigate the influence of a hyp ercholesterolemic diet enriched with coconut oil and cholesterol on carbohy drate and lipid metabolism in a rat model. Methods: Twenty male Wistar rats weighing about 190 g were assigned to two dietary groups. One group received a-semipurified control diet and the othe r was given a diet enriched in coconut oil (25% by weight) and cholesterol (1% by weight) for 26 days. Results: Our results indicated a significant increase in serum total choles terol (+285%; p<0.001), low-density lipoproteins (+154%; p<0.01), liver cho lesterol (+1509%; p<0.001), as well as a significant increase in river weig ht (+46%; p<0.001) in those rats fed the hypercholesterolemia-inducing diet as compared to controls. Moreover, a significant decrease in serum high-de nsity lipoproteins (-67%; p<0.001), triacylglycerols levels (-33%; p<0.05), and abdominal fat weight (-39%; p<0.01) were found. The observed alteratio ns in serum lipid and lipoprotein profile resembled a situation of type IIa hyperlipidemia in humans. Measurement of several enzymes concerned with li pid utilization revealed a significant increase in 3-hydroxy-3-methylglutar yl-CoA reductase activity (+68%; p<0.01) in the liver of animals fed the hy percholesterolemic diet, while a significant reduction in plasma lecithin-c holesterol acyltransferase activity (-66%; p<0.001) was found. The situatio n of hypoglycemia (-18%; p<0.05) was accompanied by lower levels of serum i nsulin (-45%; p<0.01) and liver glycogen(-30%; p<0.05) in the hypercholeste rolemic rats. Furthermore, glucose utilization was altered since lower gluc ose-6-Pase (-33%; p<0.05) and increased glucokinase (+212%; p<0.001) activi ties in the liver were found in the rat model of hypercholesterolemia. Conclusion: These results provide new evidence that a diet-induced hypercho lesterolemia in rats is associated with several adaptative changes in carbo hydrate metabolism. These findings may be of importance not only considerin g the role of western diets on cholesterogenesis, but also in other metabol ic disturbances involving lipid and carbohydrate metabolism.