COMPARISON OF PLASMA-LIPIDS AND VITAMIN-E IN YOUNG AND MIDDLE-AGED SUBJECTS ON POTATO CRISPS FRIED IN PALMOLEIN AND HIGHLY OLEIC SUNFLOWER OIL

We previously found no difference in healthy young adults' plasma chol esterols between palmolein and olive oil as the major dietary lipid, a lthough the former is high in palmitic acid (16:0) but the latter in o leic acid (18:1 cis). In the experiment reported here we compared the effects of palmolein against another monounsaturated oil, highly oleic sunflower oil (HOSO), on plasma cholesterol in both young and middle- aged healthy adults. The test oils were provided as frying oil of pota to crisps (150 g/day in men; 100 g/day in women) against low-fat backg round diets in free-living motivated volunteers. The design was a rand omised double-blind 4-week/3-week crossover trial. Compliance was moni tored with continuous dietary diaries and by measuring (fasting) plasm a lipid fatty-acid pattern. Plasma Lipids and vitamin-E compounds were measured at the start and twice at the end of each test period. In co mbined young plus older subjects (n = 42) mean plasma total and low-de nsity-lipoprotein cholesterol (LDL-c) values were both 7% (significant ly) lower on HOSO than on palmolein, but because high-density-lipoprot ein cholesterol (HDL-c) was also 5% lower, the LDL-c/HDG-c ratio was o nly 3% lower on HOSO than on palmolein. The difference between the pre sent results with HOSO and previous results with olive oil both compar ed against palmolein suggest that olive oil is associated with higher plasma cholesterols than other monounsaturated oils. In both the young and older subgroup, LDL-c was lower on HOSO but because HDL-c moved d own too in the young subgroup, the LDL-c/HDL-c ratio was lower on HOSO only in the older subjects. Palmolein has an unusual pattern of E vit amins, with a high content of tocotrienols, notably the gamma-isomer. Unlike alpha-tocopherol however, there was no sign of these tocotrieno ls in subjects' plasmas.