EFFECT OF DIETARY FATTY ACID UNSATURATION AND VITAMIN E INTERACTION ON SERUM AND LIVER LIPIDS IN RATS

Authors: MOHAMED, ALI - VA ST UNIV, BLACKBURG; HUSSEIN, AHMED - UAE UNIV, AL-AIN, EGYPT; Bhathena, Sam; HAFEZ, Y - UNIV MD EASTERN SHORE, MD

Submitted to: Journal of Nutritional Biochemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/4/2002
Publication Date: N/A
Citation: N/A

Interpretive Summary: We studied the effect of dietary fats with varying degree of unsaturation namely, coconut oil, olive oil and menhaden oil, on serum and liver lipid composition. Since unsaturated fatty acids are readily oxidized, we also studied the interaction between dietary fats and vitamin E, which is an antioxidant. We observed that serum total cholesterol and triacylglycerol were significantly lower in rats fed menhaden oil than in those fed olive or coconut oil, while the HDL-cholesterol was significantly higher in serum of rats fed menhaden oil and olive oil than in those fed coconut oil. In liver, total cholesterol was significantly higher in rats fed coconut oil than in rats fed menhaden oil. Total liver phospholipids were lower in rats fed either coconut oil or olive oil compared to those fed menhaden oil, especially with higher levels of vitamin E intake. In liver significant negative correlation was observed between phospholipids and cholesterol. The data show that vitamin E levels in the diet have only marginal effect on plasma and liver lipids. Higher levels of vitamin E in the diet appear to increase triacylglycerols and phospholipids in livers of rats fed menhaden oil. This may be due to reduction of oxidation of menhaden oil by higher doses of vitamin E. We conclude that the type and amount of unsaturation (polyunsaturated fatty acids in menhaden oil, monounsaturated fatty acids in olive oil and saturated fatty acids in coconut oil), have significant effects on plasma and tissue lipids. These data will help nutritionists, dietitians and medical professionals in recommending type and amount of fat for proper nutrition of the general population.

Technical Abstract: The effect of dietary fats with varying degree of unsaturation in the presence of different concentrations of vitamin E on tissue lipid levels was studied in rats. Rats were fed either menhaden oil, olive oil or coconut oil at 15% level with three levels of vitamin E as a-tocopherol for four weeks. The oils were analyzed for their fatty acid content. Rat serum and liver were analyzed for lipid composition. In addition, fatty acid composition of serum lipids was also analyzed. Level of vitamin E in the diet had significant effect on serum cholesterol and liver phospholipids. Serum total cholesterol and triacylglycerol were significantly lower in rats fed menhaden oil than in those fed olive or coconut oil, while the HDL-cholesterol was significantly higher in serum of rats fed menhaden oil and olive oil than in those fed coconut oil. In liver, total cholesterol was significantly higher in rats fed coconut oil than in rats fed menhaden oil. Total liver phospholipids were lower in rats fed either coconut oil or olive oil compared to those fed menhaden oil, especially with higher levels of vitamin E intake. In liver significant negative correlation was observed between phospholipids and cholesterol. The data show that vitamin E levels in the diet have only marginal effect on plasma and liver lipids. Higher levels of vitamin E in the diet appears to increase triacylglycerol and phospholipids in livers of rats fed menhaden oil. This may be due to reduction of oxidation of menhaden oil by higher doses of vitamin E. The type and amount of unsaturation (polyunsaturated fatty acids in menhaden oil, monounsaturated fatty acids in olive oil and saturated fatty acids in coconut oil), have significant effects on plasma and tissue lipids.