The effect of dietary linoleic acid on blood pressure and erythrocyte sodium transport.

: The influence of an increase in the polyunsaturated fat linoleic acid on blood pressure and erythrocyte membrane sodium transport was investigated in normotensive first degree relatives of hypertensive patients and controls by the double blind administration of safflower oil or paraffin oil (placebo) capsules for four weeks separated by a four week washout period. Systolic blood pressure fell in the controls with linoleic acid supplementation but there was no significant change in total sodium efflux rate constant. When the pattern of response was compared the changes in supine systolic blood pressure, plasma renin activity, total and ouabain-sensitive sodium efflux rate constant were significantly different in the controls compared to the relatives. These results show that dietary linoleic acid supplementation may have effects on ionic fluxes across cell membranes and cause a modest fall in blood pressure. In addition, since the response to the change in fat intake was different in the relatives and the controls, this provides further evidence of differences in the physicochemical structure of the plasma membrane in hypertensive subjects and their offspring.