Effects of polyunsaturated fats on lipid metabolism in patients with hypertriglyceridemia.

Abstract

A B S T R A C T Studies were carried out on the effects of polyunsaturated fats on lipid metabolism in 11 patients with hypertriglyceridemia. During cholesterol balance studies performed in eight patients, the feeding of polyunsaturated fats, as compared with saturated fats, caused an increased excretion of endogenous neutral steroids, acidic steroids, or both in most patients.Increases in steroid excretions were marked in some patients and generally exceeded the decrement of cholesterol in the plasma compartment. The finding of a greater excretion of fecal steroids on polyunsaturated fats in hypertriglyceridemic patients contrasts to the lack of change in sterol balance previously reported for patients with familial hypercholesterolemia; however, other workers have found that polyunsaturated fats also enhance steroid excretion in normal subjects.In most of the patients, simultaneous studies were carried out on biliary lipid composition, hourly outputs of biliary lipids, and pool sizes of bile acids. In several but not all patients, fasting gallbladder bile became more lithogenic after institution of polyunsaturated fats. This increased lithogenicity was not due to a decrease in bile acid pools; in no case was the pool decreased by polyunsaturated fats. On the other hand, two patients showed an increased output of biliary cholesterol, and frequently there was an increase in fecal neutral steroids that were derived from cholesterol; thus, polyunsaturated fats may increase bile lithogenicity in some patients through mobilization of cholesterol into bile.Reductions in plasma cholesterol during the feeding of polyunsaturated fats was seen in most patients, and these changes were usually associated with a decrease in concentration of plasma triglycerides. In fact, the de-

Transport of Very Low Density Lipoprotein Triglycerides in Varying Degrees of Obesity and Hypertriglyceridemia

“…They assumed that for the remaining patients single-exponential analysis should provide a reasonable approximation. It should be emphasized that in most of these previous studies, decay curves were followed for only [12][13][14][15][16][17][18] h, whereas the departure from log-linear decay is often not readily apparent until later times.…”

“…These diets, before initiation of the test diet, consisted of solid foods, liquid formula, or a combination of the two (13). Fat was eliminated from the diet 36 h before study to eliminate contributions from dietary chylomicrons and their degradation products, but the carbohydrate and protein intake were continued as frequent small feedings (every 3 h) of liquid formula.…”

Triglyceride and cholesterol metabolism in primary hypertriglyceridemia.

“…After a brief period of stabilization (3 to 4 days), patients were started on a diet of mixed solid food and liquid formula. 16 Caloric intakes were adjusted so that body weights were constant throughout the study period of 4 to 6 weeks. During this time, the following tests were carried out: 1) plasma cholesterol and TG twice weekly; 2) plasma postheparin lipoprotein lipase (LPL) and hepatic tryglyceride lipase (HTGL) in the third week; 3) turnover of plasma VLDL-TG at the end of their hospitalization; and 4) cholesterol balance throughout the study.…”

“…VLDL was isolated by preparative ultracentrifugation, and specific activities of VLDL-TG were estimated along with VLDL-cholesterol, as recently described. 15 From plasma activities of VLDL-TG, several parameters of VLDL metabolism were determined by the technique of Zech et al 15 Details of methodology and validation of this kinetic approach have been set forth in detail by Zech et al 16 and Berman. 21 The parameters calculated from kinetic analysis include transport (production) rates, fractional catabolic rates (FCR), and relative inputs through fast and slow synthetic pathways.…”

Hypothesis into Theory – the Development of Aetiological Concepts of Ischaemic Heart Disease: A Review

“…Experience with several dietary trials has been reassuring (Ederer et al 1971, Heady 1974). An increased incidence ofgallstones occurred in the Los Angeles trial involving a high polyunsaturated fatty acid intake (Sturdevant et al 1973), but not in the Helsinki trial (0 Turpeinen, 1974, personal communication); lithogenicity of bile increases in some subjects at the extremely high polyunsaturate/saturate ratio of 7: I (Grundy 1975). By contrast the prudent diet has a PIS ratio of about I: I; and as it is also designed to reduce obesity its net effect on gallstone frequency may well be favourable.…”