Journal Name:
Prostaglandins, Leukotrienes and Essential Fatty Acids
Article Title:
Elevated plasma fibrinogen caused by inadequate α-linolenic acid intake can be reduced by replacing fat with canola-type rapeseed oil
Date Written:
2010
Volume:
83
Number:
N/A
Page:
45-54
Author(s):
Seppänen-Laakso, T.; Laakso, I.; Lehtimäki, T.; Rontu, R.; Moilanen, E.; Solakivi, T.; Seppo, L.; Vanhanen, H.; Kiviranta, K.; Hiltunen, R.
Article:
Over the long term, imbalanced proportions of saturated, monounsaturated and polyunsaturated (n-6 and n-3) fatty acids in the diet can lead to adverse health effects. In Western diets, severe health problems may be resolved not through the treatment of cholesterol levels alone, but through balancing the n-6:n-3 ratio by reducing intake of n-6 polyunsaturated fatty acids (PUFA). Excessive n-6 eicosanoid actions may be found in a number of fatal cardiovascular events. Their effects can be diminished by competing n-3 eicosanoids originating from long chain n-3 PUFA. However, a high intake of PUFA can increase the susceptibility of lipoproteins to oxidation.
In the 1970’s Finland had the highest rate of mortality from coronary heart disease (CHD) in the world. A 20-year study aimed at reducing classical risk factors, which included lifestyle changes and the substantial replacement of animal fats by vegetable fats, led to a drastic decline in CHD mortality.
This study examined the effects of substituting dietary fat with canola oil on serum lipids, plasma fibrinogen, lipid oxidation and fatty acid composition of healthy subjects. The mechanism of alpha-linolenic acid (ALA) metabolism in subjects that do not consume fish was also investigated. The study lasted for 6 weeks in a parallel design, and tested both cold-pressed and regular canola oil. Forty-two subjects completed the study, of which 32 were non-fish eaters.
Fat substitution was an average of 24% of daily fat intake. As a result of the substitution, dietary saturated fat decreased, and MUFA and PUFA increased. ALA intake doubled, and the LA/ALA ratio decreased from 6.4 to 4.1. This resulted in a decrease in long-chain n-6 PUFA at three weeks. In the elevated fibrinogen group (2.6-3.9 g/L), fibrinogen levels decreased by 0.95 g/L at 6 weeks. The level of docosahexaenoic acid (22:6n-3) in plasma phospholipids increased in the low fibrinogen group only.
The research group concluded that the fatty acid composition of canola oil is closest to the optimum to meet the basic requirements for essential fatty acids in the body. In addition, the ALA in canola oil can favourably affect hemostasis by reducing plasma fibrinogen.
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