Effects of oleic-rich and omega-3-rich diets on serum lipid pattern and lipid oxidation in mildly hypercholesterolemic patients

Aims: To evaluate which dietary fat elicits the best response in terms of plasma lipids, lipoproteins, and oxidative processes. Methods: After a 4-week run-in period, 14 mildly hypercholesterolemic subjects were fed two balanced diets for 6-week periods. During the first intervention period, patients received a monounsaturated fatty acid (MUFA)-enriched diet (olive oil diet). During the second period this diet was supplemented by n-3 polyunsaturated fatty acids (PUFAs) (n-3 diet). Results: After the olive oil diet, a significant decrease in total serum cholesterol (−8.54%, P<0.01), and in apolipoprotein B (Apo B) (−10.0%, P<0.01) was observed. With the addition of n-3 fatty acids no further significant changes in serum lipid concentrations were found. However, the n-3 diet was followed by an increase in lipoperoxides in isolated native low-density lipoprotein (LDL) (67.23%, P<0.01).Conclusions: A beneficial effect on the serum lipid pattern was observed with the olive oil-enriched diet. The lack of further beneficial modifications on blood lipids and lipoproteins and the increase in the oxidative susceptibility of LDL observed after the addition of n-3 PUFA to the olive oil diet does not favor the use of this diet in hypercholesterolemic patients if it is not associated with a high intake of antioxidants.