Key Findings:
In mildly hyperlipidaemic postmenopausal women, the daily consumption of soy and linseed containing foods plus canola oil, resulted in clinically significant improvements of plasma cholesterol after 3 weeks. Following 8 weeks of continuous dietary supplementation, the reductions in lipids was still apparent. The authors hypothesized that the flaxseed gums and components contained within the whole flaxseed may contribute to cholesterol reduction by increasing bile acid excretion with increased laxation, or through lignan modulation of cholesterol metabolizing enzymes. The higher ALA intake from both flaxseed and canola oil may also have played a role. The study shows that incorporating foods with active nutrients into a regular diet can help to prevent and treat cardiovascular risk factors.
Abstract:
Foods such as breads and breakfast cereals enriched with a combination of soy protein (soy grits and/or soy flour) and whole linseed are gaining popularity. Regular consumption of either whole grains or soy protein can lower risk factors for coronary heart disease. Furthermore, linseed is a rich source of the omega-3 fatty acid, α-linolenic acid (LNA), with purported cardiovascular benefits. The aim of this study was to determine the effect of daily consumption of soy and linseed containing foods and Canola (as an added source of LNA) on plasma lipid concentrations in 20 mildly hypercholesterolaemic postmenopausal women. Fasted blood samples were taken initially and after 3 and 8 weeks to assay plasma lipids and both plasma and erythrocyte membrane fatty acids. Urinary isoflavones were also measured. Data from 18 subjects were used for analysis. Plasma total, low-density lipoprotein (LDL) and non-high-density lipoprotein (HDL) cholesterol concentrations fell significantly (10, 12.5 and 12%, respectively) within 3 weeks. Although attenuated, there were still significant reductions in total and non-HDL cholesterol (5 and 6.5%, respectively) after 8 weeks of intervention. These reductions were associated with increases in urinary isoflavone excretion. This pilot study indicates that regular inclusion of foods containing soy and linseed in the diet may improve plasma lipids in subjects with hypercholesterolaemia. (Author’s abstract)