Effects of restriction of dietary fat and cholesterol upon serum lipids and lipoproteins in patients with hypertension

Abstract

T HE effects of drastic restriction of dietary fat intake and elimination of cholesterol intake upon serum lipid patterns in patients with hypertension have been presented previously as part of an investigation of the Kempner rice diet.’ This therapeutic diet, which contains no cholesterol, practically no fat and only minimal amounts of protein, is of particular interest in the study of lipid metabolism in man. The investigations previously reported gave rise to the following findings: (1) A moderate decline in the average serum cholesterol levels was seen in most patients on the rice diet; in no case did the levels decrease below the normal range. (2) A neutral fat lipemia, together with an increase in serum lipid phosphorus and a decreased percentage of esterified cholesterol, was observed in one-third of the patients. The decreased percentage of esterified cholesterol was associated with the development in some patients of marked sensitivity to dicumarol and of increased values for bromsulfthalein retention and thymol turbidity. This pointed to the possibility that the effects on the serum lipids were brought about through impairment of hepatic function. The present report extends the studies to a larger number of patients and in addition presents observations during lesser degrees of restriction of dietary fat and cholesterol. Data on serum lipoprotein concentrations, as determined with the ultracentrifuge, are presented. Several workers have correlated the serum cholesterol concentration in man with the dietary intake of cholesterol.2-6 Within a broad range of intake levels there was no correlation with the serum total cholesterol. However, the report by Starke of studies in Kempner’s clinic demonstrated that drastic restriction of both fat and cholesterol in the rice diet produced significant decreases in the free and esterified cholesterol of serum.6 Experimental studies in man by Keys,? by Hildreths and by Mayer9 and their co-workers indicated that the intake of fats, both animal and vegetable in origin, has a definite influence upon the serum cholestero1 level. On the other hand Kinsell and co-workers asserted that fats of vegetable origin do not tend to maintain high serum cholesterol levels and may even have a depressant effect. lo The weight reduction studies of Walker et al. showed that in the presence of low to moderate fat in the diet, the serum cholesterol and lipoproteins may vary in proportion to the total caloric intake.” Investigations of the effects of dietary variations upon the serum neutral fat or total lipids have not been reported, except in the previous communication from this laboratory. l Thus the lipemia observed in certain subjects during rice diet treatment has not received further elucidation.