Apolipoprotein E phenotype and diet-induced alteration in blood pressure.

The purpose of the study was to answer the following two questions. First, are the diet-induced changes in the plasma cholesterol concentration associated with a change in blood pressure? Second, is the possible diet-induced change in blood pressure related to the apolipoprotein E (apo E) phenotype? Two hundred employees of our hospital volunteered and among those, 23 subjects with the apo E3 (E3,3) and 21 with the apo E4 phenotype (E4,3 or 4,4) were selected. The apo E groups were age- and sex-matched. Study subjects were healthy, had normal body weights, and their mean (+/-SD) age was 37.9 +/- 7.7 y. The total energy derived from dietary fat was 37%, 26%, and 38% during the baseline, low-fat, and high-fat diet periods, respectively. The two intervention diets were consumed by the study subjects for 4 wk at a time. During the trial blood pressure was measured once a week with an automatic device under standardized conditions. Systolic, diastolic, and mean arterial pressures were significantly reduced during the low-fat diet period compared with baseline, but not compared with the high-fat diet period among the apo E4 subjects only (-6%, -4.5%, and -6%, respectively). The high-fat diet was associated with elevation of blood pressure among 70% of study subjects. A slight but significant positive correlation was noted between the plasma total cholesterol concentration and blood pressure, more so among the apo E4 subjects. Furthermore, age was correlated with blood pressure response in apo E4 subjects. In conclusion, both the systolic and diastolic blood pressures were significantly altered during the different diet periods. The dietary response of blood pressure seemed to differ between subjects with the apo E4 and those with the apo E3 phenotype.