Top 7 things to know about using plant sterols and stanols to reduce blood cholesterol levels
Plant sterols and stanols are naturally occurring substances that have a chemical structure similar to that of cholesterol. They are found naturally in very small quantities in plant-based foods such as vegetable oils, seeds, nuts, legumes, grains, fruit and vegetables. Nutritional scientists have found they are clinically proven to lower cholesterol, if eaten in large enough quantities.
Food companies have fortified foods such as fat spreads (margarine), milk and mini yogurt drinks with quantities of sterols and stanols known to reduce blood cholesterol levels.
1. Do sterols and stanols work in lowering cholesterol?
Yes they do! There is very strong scientific evidence from many human clinical controlled trials that sterols and stanols reduce blood cholesterol levels and can be used to reduce cholesterol levels as part of a healthy diet.
Based on these studies, scientists found that consuming between 1.5 and 3 grams of sterols and stanols each day can reduce blood cholesterol levels by 7 to 12.5%. It is also clear from the evidence that as the quantity increases up to 3g each day the benefit increases, however there is little additional benefit from eating more than 3g each day.
In fact, the European Food Safety Authority reviewed all the evidence and concluded that it was robust enough to allow food companies to use the following health claim on the labels of fat spreads, dairy products, mayonnaise and salad dressings that contain between 1.5 and 3 grams of sterols or stanols in a daily intake:
“Plant sterols and plant stanol esters have been shown to lower/reduce blood cholesterol. High cholesterol is a risk factor in the development of coronary heart disease.”
2. How do sterols and stanols reduce blood cholesterol?
As part of our normal digestion, cholesterol-rich bile is emptied into the gut by the gall bladder and aids digestion by emulsifying the fat from our food. This cholesterol from the bile is normally reabsorbed into the blood further down the gut.
Sterols and stanols have a similar chemical structure to cholesterol so they partially block the cholesterol absorption which has the effect of lowering the amount of cholesterol in the blood, with the cholesterol leaving the body in the faeces (poo).
Sterols and stanols work in the same way to reduce blood cholesterol and are equally effective.
3. What is the best way to include sterols and stanols in my diet?
Unfortunately relying on sterols and stanols found naturally in plants is not enough to reduce your blood cholesterol.
Fortified foods are formulated to give you enough sterols and stanols in the suggested daily amount to lower your blood cholesterol levels.
For fortified spreads and milk the suggested daily amount is normally three portions a day, where a portion is about two teaspoons of spread or 250mls of milk. While fortified mini yogurt drinks provide the daily requirement in one serving.
The type of food, whether a mini yogurt drink, milk or a fat spread does not affect the effectiveness of the sterols and stanols.
It takes around 2 to 3 weeks for the fortified food to work and if you stop eating them your blood cholesterol will increase to previous levels. So you need to eat them consistently to be effective.
Studies have found that to get the most benefit from the fortified food it is important to include them with a main meal.
4. Is it safe to combine sterols and stanols with cholesterol lowering drugs my doctor has prescribed for me?
Yes! Sterols and stanols can be taken alongside statins and they have an additive effect. This is because they work in a different way to reduce blood cholesterol (statins reduce the quantity of cholesterol produced by the liver). It's a good idea to mention to your health professional that you have added plant sterols/stanols to your diet, as it may affect the dosage of medication required.
There is little evidence that sterols and stanols are effective for people taking ezetimibe as they work in a similar way to sterols and stanols by blocking cholesterol absorption from the gut.
5. Are sterols and stanols suitable for everyone?
They are not suitable however for pregnant and breast-feeding women and children under the age of 5 years. This is because these groups have specific nutritional needs and lowering cholesterol is not normally a priority for them.
For those that do not have high blood cholesterol levels there is no real health benefit.
There is not enough research on the effectiveness of sterol and stanol supplements and supplements cannot make a claim stating a percentage reduction in blood cholesterol, unlike fortified foods which can make this claim.
The quantity of the sterol or stanol in supplements may not be consistent and often not clearly defined, and research shows that the time for the capsule to breakdown in the gut varies and can affect their effectiveness.
As with all food supplements they may contain additional ingredients that can interfere with medications or medical conditions, and may have side effects.
7. Can you use fortified spreads in recipes?
Spreads fortified with sterols and stanols can be used instead of butter as an ingredient in many recipes.