Lipoprotein profiles and serum peroxide levels of aged women consuming palmolein or oleic acid-rich sunflower oil diets

Abstract

Objective: To investigate the hypercholesterolemic effects of a dietary exchange between 16:0 and 18:1 while 18:2 was at relatively lower level (≈4%) in aged women with initially high total serum cholesterol (TC) and low density lipoprotein cholesterol (LDL-C) values and with high intakes of dietary cholesterol.

Design: Subjects were assigned to two consecutive 28 d periods. In the first period all subjects followed an oleic acid-rich diet in the form of oleic acid-rich sunflower oil. This was followed by a second period rich in palmitic acid in the form of palmolein. Nutrient intakes, serum lipids, lipoproteins, antioxidant vitamins, peroxides and LDL-peroxides were measured at two dietary periods.

Setting: Instituto de Nutrición y Bromatología (CSIC), Departamento de Nutrición y Bromatología I (Nutrición) and Sección Departamental de Química Analítica, Universidad Complutense, Madrid, Spain.

Results: The palmolein period led to an increase in TC (P<0.001; 17.7%) and serum apolipoprotein (Apo) B levels (P<0.001; 18.0%). LDL-C and LDL-Apo B concentrations were higher (P<0.001, 4.33±0.94 mmol/L and P<0.01, 1.08±0.20 g/L, respectively) following this period than following the oleic acid-rich sunflower oil diet (3.56±0.85 mmol/L, 0.93±0.16 g/L, respectively). No significant differences were observed in the TC/high density lipoprotein cholesterol (TC/HDL-C) ratio between the two dietary periods. Serum and LDL-peroxides were lower (P<0.01, 49.5%, and P<0.001, 69.0%, respectively) after the palmolein diet than after the oleic acid-rich sunflower oil diet. The palmolein diet significantly increased TC, LDL-C, Apo B, VLDL-ApoB, LDL-ApoB in women with TC≥6.21 mmol/L or with TC<6.21 mmol/L, but the increase in Apo B, LDL-C and LDL-Apo B was greater among the women with high TC. The palmolein diet increased HDL-C in women with high or with low TC but this rise was on the borderline of statistical significance (P=0.06) only in normocholesterolemics. Serum and LDL-peroxides tended to be higher in women with TC≥6.21 mmol/L than in women with TC<6.21 mmol/L, but palmolein decreased serum and LDL-peroxide in hypercholesterolemics more than in the normocholesterolemics, resulting in serum and LDL-peroxide levels which theoretically are more adequate.

Conclusions: Though palmolein increased LDL-C concentrations, it better protected LDL particles, mainly in women with high TC, against peroxidation than did oleic acid-rich sunflower oil.

Sponsorship: This study was supported by the Spanish Comision Interministerial de Ciencia Y Tecnología (CICYT) Project No ALI-92-0289-C02-01.