Reduction of blood pressure associated with dietary polyunsaturated fat.

Evidence linking the beneficial effect of dietary polyunsaturated fat on systolic and distolic blood pressure is reported. Under controlled dietary conditions, i.e., when the polyunsaturated fat to saturate fat ratio (P/S) is maintained at about 1.0, with fat providing 25% of total energy intake, blood pressure is significantly lowered in healthy males and females in the 40- to 60-year age group. The subjects selected for these studies were either normotensive or mildly hypertensive. When the subjects resumed their usual diets, their blood pressures reverted to baseline values. Body weights of the subjects remained relatively constant in these studies, and sodium chloride intakes averaged 8 to 12 g per day. It is suggested that the lowering of blood pressure by dietary linoleic acid is mediated through prostaglandins.

Family cooperation and effectiveness in a cholesterol-lowering diet.

An average reduction in serum cholesterol approximating 10 per cent was achieved in a short-term, family-centered study in which intakes of cholesterol and saturated fats were decreased and sunflower oil and margarine were added as the major sources of polyunsaturated fats. Dietary Achievement Scores demonstrated shifts in food consumption between baseline and diet periods. Changes were evident in all fat-containing food groups; meat was the least altered. A high degree of cooperation was evident in participating families, implying the possibilities for complete family cooperation in preventive or therapeutic dietary programs. Approximately three months after the end of the test period, cholesterol levels had returned to pre-diet levels, indicating the need for continuation of the changed regimen if cholesterol-lowering is to be maintained.

The effects of carbohydrate, fat and total energy adjustment of Fredrickson's type IIb hyperlipoproteinaemia.

Fifteen patients with Fredrickson's type IIb hyperlipoproteinaemia were subjected to a 10-week dietary study during which time qualitative and quantitative alterations were carried out on the fat, carbohydrate and energy content of the diet. Significant reduction was observed in fasting serum cholesterol and triglyceride levels on substitution of polyunsaturated for saturated fat, and on total fat restriction. No changes in cholesterol and triglyceride levels were observed when dietary sucrose was replaced with complex carbohydrate, or when there was total carbohydrate restriction. The possible practical applications of these observations are discussed.

The effect of dietary polyunsaturated fat on cation transport and hypertension in the rat.

1. Essential hypertension is associated with increased intracellular sodium in both erythrocytes and leucocytes. Reports in the literature indicate that increasing the level of polyunsaturated fat in the diet reduces hypertension. In the present study, spontaneously hypertensive rats (Wistar-Kyoto, which develop systolic blood pressures in excess of 140 mmHg by 8 weeks of age) were fed on high-fat diets (40% energy derived from fat), the fat being maize oil (high in polyunsaturated fatty acids, PUFA) and coconut oil (low in PUFA). 2. Significantly higher blood pressures developed by 110 d of age in the rats fed on a high-PUFA diet, compared with those fed on the low-PUFA diet. 3. In thymocytes, ouabain-sensitive efflux rate constants were significantly lower in the group fed on the high-PUFA diet. Ouabain-insensitive efflux rate constants were unaffected by diet.