Plant Sterols and Stanols: How They Improve Health

Cardiovascular diseases are one of the leading causes of death. Plant sterols and stanols are compounds found in plant cell walls. The risk of certain types of cardiovascular diseases is reduced by consuming plant sterols/stanols. However, how do these compounds improve health? Is it safe to buy plant sterol powder from my local pharmacy? Let’s find out.

What are plant sterols and stanols?

Both plant sterols and stanols are compounds found in plant cell walls. Together they are referred to as "phytosterols." Although humans cannot synthesize these compounds, plant sterols/stanols are readily available through diet.

The National Cancer Institute defines plant sterols as a “plant-based compound that can compete with dietary cholesterol to be absorbed by the intestines, resulting in lower blood cholesterol levels.”

How do plant sterols and stanols differ?

Sterols and stanols differ in their chemical composition. Plant sterols are unsaturated compounds, and they function similarly to human cholesterol. Stanols are hydrogenated or saturated compounds. However, since plant sterols can be easily absorbed by the intestines, they are more effective than stanols. Since our diet has both sterols and stanols, they are usually referred to collectively.

How do plant sterols/stanols improve health?

One of the most common cardiovascular diseases is coronary heart disease (CHD). Coronary arteries provide blood supply to the heart. Due to cholesterol deposits or plaques, coronary arteries clog, and the blood supply to the heart muscle is diminished. Reduced blood flow to the heart causes various symptoms, such as chest pain, breathlessness, fatigue, and even a heart attack.

Luckily, the plaque build-up in blood vessels is a gradual process. Reducing the blood levels of low-density lipids (LDL) reduces the risk of coronary disease and associated complications. In 2019, for the first time, the European Society of Cardiology (ESC) and the European Atherosclerosis Society (EAS) recommended phytosterols to reduce LDL levels.

Plant sterols/stanols improve health by reducing bad cholesterol, or LDL. Research has shown two different locations of action. Firstly, plant sterols inhibit the intestinal absorption of dietary cholesterol. Additionally, they also act on biliary cholesterol in the liver to achieve a cholesterol-lowering effect.

Plant sterols/stanols have proven beneficial in reducing the risk of cancer. In animal studies, plant sterols have been useful in reducing the risk of colon cancer. In human studies, one study observed that a high intake of plant sterols reduces the risk of lung cancer by 50%. In population groups that consume high amounts of plant sterols/stanols (e.g., Seventh-Day Adventists), the risk of various cancers was lower than in the general population. For example, the role of plant sterols in reducing the risk of breast cancer is poorly understood. However, research has shown that plant sterols affect estrogen and may help in certain types of breast cancers.

Plant sterols can also help in curbing the spread of cancer. For instance, chronic inflammation plays a significant role in cancer pathology and formation of metastasis, i.e., cancer from one location (e.g., breast) spreading to other parts of the body (e.g., brain). Therefore, a strong immune system reduces the chances of metastasis. Plant sterols may stimulate the formation of cytokines, a signaling molecule, thereby reducing the risk of metastasis formation.

Are plant sterols/stanols available as pills?

Plant sterols and stanols can be obtained from various food items. Some examples of foods rich in plant sterols and stanols are:

• Vegetable oils. Wheat germ oil, sesame oil, and olive oil.
• Margarine. Vegetable oil-based margarine and mayo.
• Seeds & nuts. Pistachios, macadamia nuts, peanuts, almonds, walnuts, pecans, sunflower, pumpkin, and sesame seeds.
• Grains. Oat bran, whole wheat bran, bran, brown rice.
• Vegetables. Broccoli, cauliflower, Brussels sprouts, dill, tomatoes, sage, oregano, thyme, and paprika.
• Legumes. Dried peas, dried beans, and lentils.
• Fruits. Apples, blueberries, and strawberries.

In most grocery stores, foods fortified with plant sterols and stanols are readily available — for instance, orange juice, milk, protein bars, and bakery products. A healthy balanced meal is sufficient to meet the daily requirement of plant sterols and stanols.

However, in certain situations such as travel or camping, it may not be possible to meet daily requirements from diet only. Doctors may recommend plant sterol supplements for individuals at low cardiovascular risk and who do not meet the criteria for drugs such as statins. Many over-the-counter plant sterol/stanol supplements are available at local pharmacies, but these powders or capsules are more expensive options.

Consult a doctor before taking these supplements. Doctors may advise against these supplements in certain conditions. For instance, sitosterolemia is a rare genetic condition in which patients have an increased plasma phytosterol level. Plant sterol supplements can interfere with the absorption of fat-soluble vitamins such as vitamin E and vitamin A. Furthermore, plant sterol/stanol supplements are not recommended for pregnant women or nursing mothers. A doctor can advise patients about the correct dose and the best way to take the medicine.

Cardiovascular diseases, including hypercholesterolemia, are on the rise. A healthy diet that consists of fruits and vegetables promotes cardiovascular health. Plant sterols and stanols help in reducing blood cholesterol in certain cases. Several over-the-counter supplements are available in various forms, such as capsules or powders. Always consult a healthcare care provider before taking plant sterols or stanols supplements.