Plant sterols – How do they impact health, and where can they be found?

Key Takeaways

• Plant sterols are a group of compounds found in many different types of plants.

• Research has found that taking 2 g per day of plant sterols can lower the levels of LDL cholesterol by up to 10%.

• The structure of plant sterols is similar to that of cholesterol.

• It’s believed that plant sterols work by blocking the absorption of cholesterol in the digestive tract, because of their structural similarity.

• A wide variety of plant foods contain plant sterols, including fruits, vegetables, nuts, seeds, legumes, and vegetable oils.

• Getting a dose of 2 g per day from foods is very difficult, so some people use fortified foods or supplements to get enough plant sterols to help lower their cholesterol.

• Plant sterols are a useful addition to a healthy lifestyle, which includes exercise, a healthy diet, and most importantly, weight loss for those who are overweight. 

Cholesterol is a fatty molecule that’s found throughout the human body. It’s necessary for the body to function properly, and is used as a component of cell membranes (which surround every cell in the body) as well as to make certain hormones, vitamin D, and bile acids (which are used to digest fat). 

Although cholesterol is important, too much cholesterol is also associated with an increased risk for heart disease. For people whose cholesterol levels are too high, finding ways to lower cholesterol can help to decrease the risk of having a heart attack or stroke. Current research suggests that a group of compounds known as plant sterols may be helpful for lowering cholesterol.

What are plant sterols?

Plant sterols, also known as phytosterols, are a group of compounds that are found in many different types of plants. These compounds have a very similar structure to cholesterol. In fact, they appear to serve a similar role – plants use sterols as a building block for some of their own hormones. Plant sterols can be found in many different foods, as well as in fortified foods and supplements.

Potential health benefits of plant sterols

The primary reason that people choose to consume plant sterols is to lower LDL cholesterol. Studies have shown that consuming plant sterols can lower LDL cholesterol by approximately 10%. The maximum benefit is achieved with 2 g of plant sterols per day. Higher amounts are not harmful, but don’t add additional benefit.

There have been some studies suggesting additional benefits. For example, a few studies have shown that plant sterols might lower fasting blood sugar and hemoglobin A1c. They might also have anti-inflammatory effects. However, most of the research on plant sterols has focused on their ability to lower cholesterol, and this is the most widely accepted benefit of these compounds.

How do plant sterols work?

Researchers are still learning about how plant sterols work to lower cholesterol. The current understanding is that they act to block the absorption of dietary cholesterol from the intestines. 

The structure of plant sterols is very similar to that of cholesterol, so plant sterols actually compete with cholesterol for absorption. Their similarity to cholesterol causes them to block cholesterol from accessing sites where it can be absorbed. Because of this, less cholesterol gets absorbed from food, and the levels of cholesterol in your blood become slightly lower as a result.

Plant sterols themselves are not very well absorbed by the body. Even in people who take supplements, the levels of plant sterols in the bloodstream are very low. These compounds appear to act in the digestive tract, rather than in other parts of the body. 

Natural sources of plant sterols

A wide variety of different plant foods contain plant sterols, including:

• Vegetables (especially cruciferous vegetables such as broccoli, cauliflower, and Brussels sprouts)

• Fruits (especially berries, oranges, and avocados)

• Legumes (especially soybeans)

• Seeds (especially sesame seeds and sunflower seeds)

• Nuts (especially pistachios, almonds, and walnuts)

• Vegetable oils (and vegetable-oil based products, such as margarine)

Focusing on consuming these foods will help to ensure that you’re getting enough nutrients like vitamins, minerals, and fiber, in addition to providing you with plant sterols.

Who can consider taking plant sterols as supplements?

While eating foods that contain plant sterols can certainly be helpful, it may be difficult to get enough through food alone. It takes 2 g, or 2000 mg, of plant sterols to get the maximum cholesterol-lowering benefit. A single serving of fruit or vegetables contains approximately 14 to 16 mg of plant sterols. Although getting plant sterols through food is certainly beneficial, it would take more than 100 servings of fruits and vegetables per day to achieve an intake of 2 g, which is clearly not realistic.

To get a dose of plant sterols that’s high enough to achieve the maximum cholesterol-lowering effect, supplements are an option. People who may want to consider taking supplemental plant sterols include those who:

• Have high cholesterol

• Have a family history of high cholesterol (multiple family members whose cholesterol is very high)

• Have heart disease or atherosclerosis (hardening of the arteries)

• Have a family history of heart disease (multiple family members who had heart attacks or strokes, particularly before the age of 65)

There are also certain foods that are enriched with plant sterols. For example, some types of margarine have extra plant sterols added. This might be another way to ensure that you’re getting enough. However, consistency is important, meaning that you need to get enough plant sterols every day to get the benefits. For many people, it may be harder to achieve the required dose every day with foods than with supplements.

Side effects & things to watch out for

In general, plant sterols are considered to be safe, with few adverse effects. The main side effects of plant sterols are related to the digestive system. Some people may experience diarrhea while taking plant sterols, or there may be extra fat in their stools. These side effects occur because plant sterols reduce the body’s absorption of fats from food, which leaves more fat behind in the digestive tract.

We don’t yet have enough research to say for sure whether plant sterol supplements are safe for women who are pregnant or breastfeeding, although eating foods that contain plant sterols is considered safe.

Holistic management of high cholesterol

For people with high cholesterol, plant sterols may be one way to help bring this under control and lower the risk of heart disease. However, these compounds should not be used on their own. Instead, they’re a useful addition to a healthy lifestyle, which includes exercise, a healthy diet, and most importantly, weight loss for those who are overweight. 

NOVI Optimum Plus offers medical doctor guidance and weight loss medication, combined with personalized nutrition & fitness coaching and progress tracking via an app, to help you achieve sustainable results.