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Objective: To compare the metabolic effects of a lipid-lowering diet containing either low erucic rapeseed (canola) oil or olive oil., Methods: Twenty-two hyperlipidemic patients participated in a cross-over study comprising two consecutive 3.5-week treatment periods. The participants were free-living throughout the study period, visiting the metabolic clinic initially and at the end of each treatment period for weighing and blood sampling. All food was prepared daily and weighed out for each individual appropriate to his/her energy requirement., Results: Total serum cholesterol, low-density lipoprotein and the ratio between low-density and high-density lipoprotein cholesterol decreased to the same extent on the two diets tested, as did the apolipoproteins B, A-I and Lp(a). After adjustment for body weight changes, most of the reported effects remained virtually unaltered. However, there was a slightly greater decrease in low-density lipoprotein cholesterol with the diet containing rapeseed oil (-17%, p < 0.001) than with the olive oil diet (-13%, p < 0.01) with p < 0.04 for the difference between diets. Also, the intravenous glucose tolerance improved to a similar extent on both diets., Conclusions: The results indicate that lipid-lowering diets containing either rapeseed oil or olive oil have similar effects on serum lipoprotein concentration and glucose tolerance in hyperlipidemic subjects.

The effects of 3 wk on a diet rich in monounsaturated rapeseed oil were compared with those of a diet containing sunflower oil within a lipid-lowering diet. Ninety-five subjects with moderate hyperlipoproteinemia were randomly assigned to one of the two well-controlled diets prepared at the hospital kitchen. Total serum, low-density- and high-density-lipoprotein cholesterol concentrations decreased by 15%, 16%, and 11% (P < 0.001), respectively, on the rapeseed oil diet and by 16%, 14%, and 13% (P < 0.001) on the sunflower oil diet. Serum triglycerides decreased more markedly (by 29%, P < 0.001) on the sunflower oil than on the rapeseed oil diet (14%, P < 0.01). The n-3 fatty acids (20:5 and 22:5) in the serum phospholipids increased significantly on the rapeseed oil diet but decreased on the sunflower oil diet. There was an increase in the alpha-tocopherol concentrations after both diets. The findings indicate that low erucic acid rapeseed oil can replace oils and fats rich in polyunsaturated fatty acids in a lipid-lowering diet.

Controlled comparisons of the effects of monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) as a part of lipid-lowering diets in persons with hyperlipoproteinaemia are sparse. The present study was carried out at a metabolic ward. Forty hyperlipidaemic patients (25 hypercholesterolaemic and 15 hypertriglyceridaemic) were given a 3-week diet rich in either MUFA (saturated fatty acids 7.3 energy% (E%), MUFA 14.6 E%, PUFA 4.8 E%) or PUFA (saturated fatty acids 7.8 E%, MUFA 8.4 E%, PUFA 10.4 E%), but otherwise with an identical composition. The mean serum cholesterol reduction on the MUFA diet was 12% (P < 0.001), with a low density lipoprotein cholesterol reduction of 11% (P < 0.001). The corresponding reductions on the PUFA diet were 15% (P < 0.001) and 16% (P < 0.001). The serum apolipoprotein B and A-I concentrations decreased highly significantly by 13% and 11% on the MUFA diet and by 14% and 11% on the PUFA diet. None of these changes differed between the two diets. Neither were there any differences between the diets regarding the effects on blood glucose, serum insulin and plasma fibrinogen, but there was a significant decrease in serum insulin with a significant reduction of the insulin/glucose ratio after the MUFA diet. The results of this study indicate that MUFA and PUFA are interchangeable within the given frames in lipid lowering diets even in patients with hyperlipidaemia.

Nine hyperlipoproteinaemic patients were treated with a serum lipid-lowering diet during 4 weeks in a metabolic ward. The diet contained 35% energy from fat and the ratio between polyunsaturated and saturated fats (the P/S ratio) was 2.0. This treatment caused a reduction of the serum concentrations of the low density lipoprotein cholesterol (Chol) by 17% (P less than 0.01), of the apolipoprotein (apo) B by 27% (P less than 0.01), of high density lipoprotein (HDL) Chol by 15% (P less than 0.05) and of the apo A-I by 9% (P less than 0.02). The apo B/apo A-I ratio decreased by 19% (P less than 0.01). It is suggested that the reduced HLD Chol and apo A-I concentrations may be due to both the qualitative change to more polyunsaturated fats in the diet and to the reduction of the total dietary fat intake.

Three lipid lowering diets for treatment of different types of hyperlipoproteinemia were prepared based on ordinary Swedish food. Seven different daily menus were planned with an identical composition at all energy levels. The fat and protein content provided 34-35% and 20% of the energy, respectively. The ratios between polyunsaturated and saturated fatty acids varied in the three diets between 1.3 and 2.0. The cholesterol content was 0.14 g per 6.7 MJ. The effects of the diets were evaluated under isoenergetic conditions in 45 hyperlipoproteinemic patients during 2 weeks. The concentration of the very low density lipoprotein triglycerides decreased by 27-33%, the low density lipoprotein by 16-19% and the high density lipoprotein cholesterol by 5-13% compared with the concentrations during a preceding 2-week period on a control diet. No changes of the lipoprotein removal capacity indicated that the effects were mainly due to a reduced production of serum lipoproteins.

The feasibility of reducing serum lipoprotein levels in patients with atherosclerotic disease by combining diet, clofibrate and nicotinic acid (niceritrol) has been investigated. An additive lipid-lowering effect of diet and the two drugs was demonstrated. It was possible to reduce the serum triglycerides (TG) in hypertriglyceridaemic patients by 50-60%. This corresponded to a reduction of very low density lipoprotein (VLDL) TG by 73 and 66% in patients with hyperlipoproteinaemia (HLP) type IIB and IV, respectively. In normotriglyceridaemic patients the serum TG concentration decreased by 30-40%. The serum cholesterol (Chol) concentration was reduced by 33% and the low density lipoprotein (LDL) Chol by 37% in HLP type IIA and IIB. The LDL Chol decreased by 32% in normolipoproteinaemic patients and by 21% in HLP type IV. The mean value for serum cholesterol after therapy was in all groups close to 200 mg/100 ml. In hypertriglyceridaemic patients high density lipoprotein (HDL) Chol increased by 18%. Clofibrate and niceritrol differed with regard to the effect on serum lipoprotein concentrations as well as on other metabolic parameters. Niceritrol was significantly more effective than clofibrate in lowering LDL Chol and in increasing HDL Chol. Niceritrol treatment significantly reduced the Chol/TG ratio in VLDL while no such effect was seen during clofibrate administration. The two drugs also showed significantly different effects on the fractional removal rate (K2) of triglyceride-rich lipoproteins as measured by the intravenous fat tolerance test (IVFTT). The K2 was significantly increased by clofibrate but was not affected by niceritrol treatment. The two drugs differed also with regard to the effects on serum uric acid concentration and the liver function tests. The plasma fibrinogen levels and the erythrocyte sedimentation rates were reduced during treatment with both niceritrol and clofibrate. The present study demonstrates that it is possible to obtain substantial reductions of serum lipoprotein concentrations by combining lipid-lowering diet, clofibrate and niceritrol treatment. There was an additive lipid-lowering effect of this treatment and the combination of the two drugs seemed beneficial in regard to certain possible side effects. The impact of a lipid reduction within this range on cardiovascular morbidity and mortality remains to be evaluated.

A simplified rapid quantitative method for determination of sterols in food is described. The lipids were extracted in chloroform-methanol and saponified. The unpolar components, containing the sterols, were extracted with petroleum-ether (PE) and prepared for the gas liquid chromatography (GLC). Progesterone (4-pregnene-3, 20-dione) was used as an internal standard for the GLC analysis. The recovery of the procedure was studied by adding cholesterol-7-alpha-3H before extracting the lipids. Average recovery of the method was 87.4 +/- 8.5%. The analytical errors for determination of the sterol content of three different diets were 10, 20, 25 and 15% for cholesterol, campesterol, stigmasterol and beta-sitosterol respectively.

Seventeen patients with hypertriglyceridaemia were given a lipid-lowering diet with a high P/S-ratio 2.1 during a 3-week period. The very low density lipoprotein triglycerides decreased by 43%, low density lipoprotein cholesterol by 19% and high density lipoprotein cholesterol by 12%. There was a marked increase of linoleic acid (18:2 n-6) in all plasma lipid esters with a concomitant decrease of the saturated and monounsaturated fatty acids. There was a slight increase of the linoleic acid metabolites 18:3 n-6, 20:3 n-6 and 20:4 n-6 in serum triglycerides whereas the fatty acids of the n-3 series decreased in all plasma lipid esters. In the platelets a similar pattern was found with an increase of linoleic acid and its metabolite 22:4 n-6 and a decrease of 18:1 n-9 as well as of the n-3 fatty acids. No significant differences in platelet reactivity was found. However, in a few patients there was an increased platelet aggregation after the diet period. Our results suggest that this diet based on a very high content of linoleic acid may not affect platelet reactivity in a beneficial way. The reason may be an increased turnover of arachidonic acid in the platelets or an imbalance between the n-6 and n-3 series of fatty acids.