What are the cardiovascular benefits of including plant sterols and stanols in a healthy diet and lifestyle?

Studies have shown that, even at their highest intakes, naturally occurring dietary plant sterols and stanols only have a modest effect on lowering cholesterol concentrations. This is because levels of plant sterols and stanols occurring in natural food sources are too low2.

Clinical studies show that foods with added plant sterols and stanols significantly lower blood cholesterol, especially LDL-cholesterol, a major CVD risk factor2.

LDL-cholesterol lowering is linked to lower CVD risk regardless of the underlying mechanism.

Numerous clinical studies have shown that foods with added plant sterols and stanols lower LDL-cholesterol in a dose-dependent manner. For an LDL-cholesterol lowering effect of 7-10%, a daily intake of approximately 2 g/day of plant sterols/stanols (see Figure 2) is needed2. An LDL-cholesterol lowering effect of 10-12% has been observed for intakes of plant sterols and stanols up to approximately 3 g/day8.

It is very difficult to achieve these amounts of plant sterols and stanols from ordinary foods in the diet2. Hence, incorporation of foods with added plant sterols and stanols in the daily diet is needed to achieve significant LDL-cholesterol reduction. Although there is no CVD outcome data for such products it is reasonable to postulate a beneficial effect on CVD outcomes based on their well-established LDL-cholesterol lowering effect.

With a daily intake of approximately 2 g plant sterols/stanols, a reduction in LDL-cholesterol can be expected in 2-3 weeks of intake and is sustained with continued consumption9.

Discontinuing the use of plant sterols and stanols will result in cholesterol levels returning to original levels.

REMEMBER: Continuous intake of plant sterols and stanols is needed to maintain the LDL-cholesterol lowering effect over time.

ADVICE: Using foods with added plant sterols and stanols can help to lower LDL-cholesterol as part of a healthy diet and lifestyle.

Figure 2 How to get the recommended daily dose of plant sterols/stanols

Choose one of these options each day

3 slices of bread each with 10 g of spread

One pot of yoghurt

One yoghurt drink

One cereal bar

Incorporating additional plant sterols/stanols in the daily diet is effective in reducing LDL-cholesterol.

Plant sterols and stanols - mode of action

The cholesterol absorption pathway represents an attractive target in the management of dyslipidemia. It offers clinical opportunities for dietary supplementation with components that can help to reduce intestinal cholesterol absorption1. Plant sterols and stanols are the most prominent of these dietary components2.

Plant sterol and stanols reduce the absorption of cholesterol from the gut by 30 to 40%, which means that less cholesterol is absorbed and circulating in the blood stream. TC and LDL-cholesterol levels are therefore reduced, with no significant effect on HDL-cholesterol levels2.

The intestinal handling of cholesterol and plant sterols and stanols occurs in three phases2:

  1. When cholesterol (either from the diet or from the bile) and plant sterols and stanols reach the small intestine, they are incorporated into particles called mixed micelles. The micelles are essential for carrying these hydrophobic compounds in the gut across the intestinal wall.
  2. Once in the micelles, uptake of cholesterol and plant sterols/stanols into the enterocytes (the intestinal absorptive cells) occurs.
  3. The bulk of absorbed cholesterol is incorporated into chylomicrons, i.e. lipoprotein particles that transport cholesterol and fats via the lymphatic system to the liver and into the blood. The bulk of plant sterols and stanols is pumped back from the enterocytes into the gut lumen and only a minimal amount will actually reach the blood circulation.

Plant sterols and stanols reduce LDL-cholesterol levels in the blood by reducing the amount of cholesterol absorbed from the intestine.

Due to the similar molecular structure, plant sterols and stanols compete with exogenous cholesterol (from the diet) and endogenous cholesterol (from the liver via the bile) for incorporation into micelles (Phase 1). By displacing cholesterol from micelles, plant sterols and stanols reduce the amount of cholesterol that is actually absorbed from the gut.

Test your knowledge
What is the mechanism of action of plant sterols/stanols?
  1. Increasing intestinal cholesterol uptake of both dietary and biliary cholesterol from the intestinal tract
  2. Increasing cholesterol metabolism
  3. Reducing intestinal cholesterol absorption by interfering with the uptake of both dietary and biliary cholesterol from the intestinal tract
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