Plant sterols are known to lower low-density lipoprotein cholesterol (LDL-C) whereas high intakes of the omega-3 fish fatty acids EPA and DHA are known to lower triglycerides. Consumption of a combination of plant sterols and EPA+DHA could therefore address these two blood lipid risk factors simultaneously, researchers hypothesized.
High circulating levels of triglycerides and LDL cholesterol have both been linked with greater risk for heart disease and strokes. Although these associations do not necessarily indicate these factors cause cardiovascular disease, people with elevated cholesterol should do what they can to reduce these blood lipids. They are advised to watch their weight, exercise regularly and choose a diet low in saturated fats, trans fats, cholesterol and salt while increasing their consumption of fruits, vegetables, whole-grains, legumes and fatty fish. Foods containing plant sterols are also promoted, as they can substantially lower LDL-cholesterol.
To test the theory that consumption of a low-fat spread enriched with plant sterols and EPA+DHA from fish oil lowers both LDL-cholesterol and triglycerides, researchers conducted a randomized, double-blind, placebo-controlled trial in which 85 men and 247 women with high blood cholesterol levels consumed one of five low-fat experimental spreads. For 4 weeks, those assigned to the control group used 30 g of margarine containing neither plant sterols nor fish oil daily. Volunteers assigned to the other groups consumed the same amount of spread fortified with plant sterols (2.5 g/d) and varying amounts of EPA+DHA (0, 0.9, 1.3, or 1.8 g/d). Blood samples were collected at the beginning and end of the study.
As hypothesized, the study concluded that consumption of a low-fat spread enriched with plant sterols and different low doses (<2 g/d) of omega-3 fatty acids from fish oil decreased triglyceride concentrations in a dose-dependent manner while also decreasing LDL concentrations. The scientists concluded: “The use of low-fat spreads enriched with both plant sterols and fish oil may thus offer an interesting opportunity for a combined blood lipid benefit that would fit in diet and lifestyle changes for improving blood lipid profiles.”