The Health Benefits of Phytosterols

Plant-based compounds may help lower your cholesterol

supplements in the shape of a heart

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Phytosterols, also known as plant sterols or stanol esters, are naturally occurring compounds found in plants that are similar in structure to cholesterol found in humans. Fruits, vegetables, nuts, and certain grains and oils add phytosterols to your diet. Some products, like juices, have phytosterols added to them.

Phytosterols can potentially lower the cholesterol levels in your blood, most especially the "bad" low-density lipoprotein (LDL) cholesterol that can clog your arteries. When taken as a supplement, phytosterols may help lower your LDL and total cholesterol levels.

This article discusses how phytosterols may help in controlling cholesterol levels. It presents other health claims (including how phytosterols can promote heart health or prevent cancer) for which there is limited research evidence and also explains who should not use phytosterols.

What Are Phytosterols?

Phytosterols are a compound found in many plant foods. A typical western diet contains approximately 300 milligrams (mg) of plant sterols, while a vegetarian diet contains between 300 and 500 mg per day.

This amount is considered small to achieve the desired reduction in LDL in people with hypercholesterolemia (a specific type of high cholesterol) or an inherited genetic disorder known as familial hypercholesterolemia.

To meet this goal, you would either need to consume phytosterol-enriched foods or take a daily supplement.

Food Sources

Foods contain phytosterols in different amounts. Soybeans, green peas, and kidney beans are excellent sources, as are many legumes often found in vegan diets. Many nuts and oils also provide phytosterols. The compounds may be added to:

  • Mayonnaise
  • Dark chocolate
  • Yogurt
  • Milk
  • Meats and cheeses

What Are the Health Benefits of Phytosterols?

The current body of research has consistently shown that eating 2 grams of phytosterols per day can reduce your LDL cholesterol by anywhere from 8% to 10%. Although many people can meet these goals by increasing their intake of phytosterol-rich foods, there are some who may benefit from a daily supplement.

With that being said, the evidence remains mixed as to whether phytosterol supplementation actually translates to a reduction in the risk of cardiovascular disease (CVD).

A 2017 review of studies from Brazil reported that a daily 2-gram phytosterol supplement reduced LDL levels in people with hypercholesterolemia by 2.7% and in people with genetically induced hypercholesterolemia by 4.3 to 9.2%.

Cardiovascular Risk

A 2012 review of studies from Germany, which evaluated 17 clinical trials from 1950 to 2010, could not find any association between phytosterol concentrations in the blood and the risk of CVD.

A 2013 study from Finland reported that a daily 3-gram intake of phytosterols reduced arterial stiffness, especially in men. Yet a 2015 study from Germany showed no discernable difference in adults following the same dietary regimen.

There's still no clear evidence that phytosterols in the diet can limit the risk of stroke, heart attack, and other CVD conditions. Researchers say longer studies of at least 10 years, following tens of thousands of people over time, are needed to better understand the impacts of phytosterols, especially relating to the prevention of atherosclerosis (hardening of the arteries).

Lowering Cholesterol

Despite the contradictory findings, most health experts agree that the reduction of LDL is beneficial no matter what the implication regarding CVD risk. What the research does definitively show is that phytosterol supplements work best when used as part of a treatment plan, which includes diet, exercise, and traditional cholesterol-lowering drugs.

Cancer Treatment and Prevention

Some studies suggest a role for phytosterols in cancer treatment and prevention. The scientific evidence is still inconclusive, but there may be benefits for people diagnosed with:

Low levels of plant sterols also have been associated with gallstone disease. Researchers continue to pursue the evidence of anti-inflammatory benefits from phytosterols, in order to manage other medical conditions including chronic kidney disease and respiratory illnesses.

Some scientists find that a diet rich in beta-sitosterol, as is the case for vegetarians and those living in Asian countries, is directly responsible (in part) for lower incidence of prostate, colon, and esophageal cancers.

Are there Side Effects From Taking Phytosterol Supplements?

The current evidence suggests that phytosterol supplements are relatively safe and well-tolerated. Side effects, if any, tend to be mild and may include constipation, nausea, upset stomach, heartburn, flatulence, and the discoloration of stools. Many of these symptoms will resolve on their own once your body adapts to the supplement.

Higher phytosterol doses are associated with an increased risk of side effects. Lowering the dose will usually resolve adverse symptoms. While phytosterol supplements are presumed to be safe over the long term, this has yet to be confirmed by research.

Phytosterol supplements should not be given to people with a rare genetic disorder called phytosterolemia (also known as sitosterolemia). The inherited disease, which causes the excessive build-up of fat in blood and tissues, can be made worse by the consumption of phytosterols.

Unless there is a diagnosis of familial hypercholesterolemia, phytosterol supplements should not be used in children. Even then, speak with your healthcare provider before starting treatment. The supplement is also not advised in pregnant or breastfeeding women due to the lack of safety research.

Drug Interactions

Phytosterol supplements may reduce the effectiveness of the cholesterol-lowering drug Questran (cholestyramine). To avoid an interaction, take the supplement several hours before or after your Questran dose.

Several studies have suggested that phytosterol supplements may reduce the absorption of beta-carotene, a precursor to vitamin A. You can usually circumvent this by taking a beta-carotene supplement or eating foods rich in beta-carotene (like root vegetables and greens).

It is unknown what other drugs phytosterol may interact with. To be safe, always advise your healthcare provider about any supplements or non-prescription drugs you are taking to avoid interactions and possible side effects.

When purchasing a dietary supplement, always choose brands that have been tested by an independent certifying body like the U.S. Pharmacopeia (USP), ConsumerLab, or NSF International. Dietary supplements are not required to undergo rigorous testing in the United States; independent certification provides better assurance of quality and safety.

What Foods Are Highest in Phytosterols?

Food should always be your first source of micronutrients, and this includes phytosterol-containing foods. These same foods tend to be high in fiber and antioxidants that protect the heart and keep your blood fats in check.

High Phytosterol-Containing Foods
Food Mg per 100 grams
Pistachios 108
Wheat germ 553
Almonds 143 
Corn oil 952
Olive oil 176
Walnuts 108
Peas 135
Kidney beans 127
Brussels sprout 24
Cauliflower 18 
Orange 24
Banana 16
Apple 12
Onion 15
Carrot 12
Cherry 12

Summary

Phytosterols occur naturally in many foods or can be added to the diet with supplements. They can potentially help you to manage LDL cholesterol levels and your overall health through lower lipid levels.

Phytosterols also are believed to have anti-inflammatory and anti-tumor properties. Studies suggest a role for sterols in preventing cancer, stroke and other cardiovascular disease, gallstones, and more.

Although tolerated well by most people, phytosterol supplements should not be used by pregnant people or children. They also should be avoided in people diagnosed with sitosterolemia. Ask your healthcare provider about sterols in your diet and how best to manage your cholesterol levels.

15 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Jennifer Moll, PharmD
Jennifer Moll, MS, PharmD, is a pharmacist actively involved in educating patients about the importance of heart disease prevention.