Journal Name:
Journal of Internal Medicine
Article Title:
Replacing dairy fat with rapeseed oil causes rapid improvement of hyperlipidaemia: a randomized controlled study
Date Written:
2011
Volume:
270
Number:
N/A
Page:
356-364
Author(s):
Iggman, D; Gustafsson, I.-B.; Berglund, L.; Vessby, B.; Marckmann, P.; Riserus, U.
Article:
Replacing saturated fat (SFA) with monounsaturated fat (MUFA) and polyunsaturated fat (PUFA) from vegetable oils has been shown in clinical trials to reduce the risk of cardiovascular disease. A possible advantage of rapeseed (canola) oil over olive oil is its content of alpha-linolenic acid (ALA) in addition to linoleic acid (LA) and oleic acid. This clinical trial provided an RO-enriched margarine as part of the intervention diet with the expectation it may exert even more favourable effects than olive oil with regard to blood lipid profiles. In addition, the effect of a high SFA diet based on dairy foods is of interest as high-fat dairy foods have been proposed to be less atherogenic than other SFA-rich foods. The goal of this study was to investigate the effect of replacing dairy fat with rapeseed oil on factors such as blood lipids, glucose metabolism and coagulation factors in hyperlipidaemic weight-stable subjects.
The study design was a 3-week randomized, controlled, two period cross-over intervention with an intermediate three week washout period. Twenty subjects (14 men and 6 women) were free-living throughout the time period, with all foods provided.
Serum total cholesterol, LDL cholesterol, total/HDL cholesterol ratio, apoB/A-I ratio and triglycerides were significantly lower following the RO diet as compared with the DF diet. Lp(a) was lower after the DF diet. HDL cholesterol levels were unchanged following either diet. Insulin sensitivity or fasting glucose concentrations did not differ between the diets, but the K-value for glucose tolerance did increase significantly compared with baseline values following the RO diet. There were no significant differences in FVIIc or PAI-1 following either diet.
It has been suggested that rapeseed (canola) oil may have optimal metabolic effects due to its fatty acid profile. This study demonstrates that replacing SFA from high-fat dairy foods with unsaturated fats from RO for three weeks causes clinically relevant beneficial effects on the serum lipid profile in weight-stable hyperlipidaemic subjects. Neither fasting plasma glucose nor insulin sensitivity was significantly affected by diet, but this may be due to the 3 week intervention period being insufficient, or the sample size being too small.
The authors conclude that replacing dairy fat with rapeseed (canola) oil causes marked improvements in serum lipoprotein profiles without significant weight loss, and that the results are especially relevant for hyperlidaemic patients at high risk for CVD.
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