EFFECTS OF NATIONAL CHOLESTEROL EDUCATION-PROGRAM STEP-2 DIETS RELATIVELY HIGH OR RELATIVELY LOW IN FISH-DERIVED FATTY-ACIDS ON PLASMA-LIPOPROTEINS IN MIDDLE-AGED AND ELDERLY SUBJECTS

The effects of two National Cholesterol Education Program (NCEP) Step 2 diets (less than or equal to 30% of energy as total fat, < 7% of ene rgy as saturated fat, and < 200 mg cholesterol/d), one relatively high and the other relatively low in fish-derived fatty acids, on plasma l ipoprotein concentrations and blood pressure were compared in 22 men a nd women with a mean (+/- SD) age of 63 +/- 10 y. Subjects were placed on a baseline diet similar to the diet currently consumed in the Unit ed States (35% of energy as total fat, 14% Of energy as saturated fat, 35 mg cholesterol/MJ) for 6 wk and then on either an NCEP Step 2 diet relatively high in fish (Step 2 high-fish, n = 11) or relatively low in fish (Step 2 low-fish, n = 11) for 24 wk. All food and drinks were provided. Compared with baseline values, consumption of both the Step 2 high-fish and the Step 2 low-fish diets under weight-stable conditio ns was associated with significant decreases in plasma concentrations of total cholesterol (-14% and -19%, respectively), low-density-lipopr otein (LDL) cholesterol (-15% and -20%, respectively), and high-densit y-lipoprotein (HDL) cholesterol (-11% and -17%, respectively). Postpra ndial, but not fasting, triacylglycerol concentrations were significan tly reduced during consumption of the Step 2 high-fish diet. There wer e no significant changes in these indexes after consumption of the Ste p 2 low-fish diet compared with the baseline diet. LDL particle size d ecreased significantly (-12%) only in subjects on the Step 2 low-fish diet. Both Step 2 diets caused small but significant reductions in dia stolic blood pressure. Our results indicate that NCEP Step 2 diets rel atively high or relatively low in fish are both effective in significa ntly reducing total and LDL-cholesterol concentrations without changes in the ratio of total cholesterol to HDL cholesterol under controlled weight-stable conditions in middle-aged and elderly subjects. A benef icial effect on diastolic blood pressure was also observed.