Phytosterols are often added to foods and supplements to improve heart health.
These compounds are known to lower cholesterol levels by reducing the absorption of cholesterol.
However, research has observed conflicting results regarding exactly how phytosterols can affect your health.
This article takes a closer look at phytosterols, including what they are, the foods they’re in, and the potential pros and cons of including them in your diet.
Phytosterols, also called plant sterols, are a family of molecules related to cholesterol.
They are found naturally in a variety of plants. Like cholesterol, they are a key structural component of cell membranes (
Campesterol, beta-sitosterol, and stigmasterol are the most common plant-based phytosterols that you get from your diet. They’re found naturally in foods like nuts, seeds, and vegetable oils, and they’re added to some processed foods like margarine (
Since phytosterols can block the absorption of cholesterol, they are often touted as a way to improve heart health and lower blood levels of LDL (bad) cholesterol (
However, it is estimated that only around 2% of phytosterols in food are absorbed by your body, compared to around 50% of cholesterol (
Phytosterols are a type of compound found in nuts, seeds, vegetable oil, and margarine. They are often used to lower cholesterol levels, although your body only absorbs small amounts of them.
Many healthy plant foods contain considerable amounts of phytosterols, including (
- Nuts: pistachios, macadamia nuts, almonds, cashews, peanuts, hazelnuts
- Seeds: pumpkin seeds, sunflower seeds, watermelon seeds
- Fruits: pineapple, oranges, berries, bananas, apples, apricots
- Vegetables: artichokes, broccoli, green beans, cabbage, asparagus, sweet potatoes, celery, cauliflower
- Legumes: chickpeas, lentils, mung beans, adzuki beans, soybeans
- Oils: olive oil, argan oil, sunflower oil, canola oil
For this reason, some research has shown that people on a vegan or vegetarian diet generally consume more phytosterols than people on a non-vegetarian diet (
Likewise, the diet of the ancient Paleolithic hunter-gatherers, which was rich in plant foods like nuts and seeds, is estimated to contain around 2.5 to 5 times more phytosterols than the average modern diet (
While these ancient groups of people got a lot of phytosterols from plant foods, many people today regularly receive added phytosterols from refined vegetable oils and processed foods like margarine.
Additionally, grains contain phytosterols and can be a good source for people who consume a lot of grains (
It is generally believed that consuming at least 2 grams of phytosterols per day could significantly reduce LDL (bad) cholesterol levels (
For reference, 1 cup (170 grams) of chickpeas contains approximately 206 mg of phytosterols, a 3.5 ounce (100 gram) serving of sweet potato contains 105 mg and 1 tbsp (14 grams) of herbal oil. sunflower contains 69 mg (
Keep in mind that refined vegetable oils, margarine, or phytosterol supplements do not provide other beneficial nutrients like fiber or vitamins C, K or A. So, it is best to just eat more food. whole containing phytosterols if desired. increase your consumption.
Plant foods like nuts, seeds, vegetables and legumes are rich in phytosterols. Many people also regularly consume refined vegetable oils and processed foods that often contain added phytosterols.
Studies show that phytosterols can offer several benefits, especially when it comes to cholesterol levels and cancer risk.
May lower cholesterol levels
In your gut, phytosterols compete with dietary cholesterol for certain enzymes necessary for their metabolism. It can reduce the absorption of cholesterol by 30-50% (
According to one study, consuming at least 2 grams of phytosterols per day could lower your blood level of LDL (bad) cholesterol by about 8-10%. However, it should be noted that this study used high dose supplements, not natural food sources (
Phytosterols are especially useful for people with high cholesterol because they have been shown to increase the effectiveness of statins, a type of cholesterol-lowering drug (
Although cholesterol does not directly cause heart problems, high cholesterol in the blood is a risk factor for heart disease (
May reduce the risk of certain cancers
Some evidence suggests that phytosterols may reduce the risk of certain cancers.
Human studies show that consuming large amounts of phytosterols may be linked to a lower risk of stomach, lung, liver, breast, prostate and ovarian cancer (
Test-tube and animal studies also indicate that phytosterols may have anti-cancer properties and may slow the growth and spread of tumors (
Keep in mind, however, that studies in humans do not take into account other factors that might play a role in the development of cancer, such as family history, physical activity, consumption of alcohol and smoking.
Additionally, numerous test-tube and animal studies have been conducted using large amounts of highly concentrated phytosterols that exceed the amount you would naturally get from your diet.
Therefore, more research is needed to determine how phytosterols can affect cancer growth in humans when consumed in normal amounts as part of a healthy diet.
Phytosterols can lower cholesterol levels by 8-10%. Some studies also suggest they may be linked to a lower risk of cancer, although more research is needed.
While phytosterols can be associated with several benefits, there are also a few drawbacks to consider.
May increase plaque buildup
Some research shows that phytosterols may increase the buildup of plaque in your arteries, which can contribute to a condition known as atherosclerosis (
This can narrow the arteries, making it harder for your heart to pump blood throughout your body (
This is of particular interest to people with a genetic condition called sitosterolemia. Sitosterolemia causes the body to absorb large amounts of phytosterols into the bloodstream, which increases the risk of plaque build-up and heart disease (
Yet the research is contradictory.
For example, older and more recent studies in humans and animals have shown that increased consumption of phytosterols is not associated with a higher risk of atherosclerosis. On the contrary, they found that it can promote blood circulation by dilating blood vessels (
As such, more research is needed on the subject.
May increase risk of heart disease
Although research shows that phytosterols may lower LDL (bad cholesterol) levels, studies to determine if they can reduce the risk of heart disease have shown mixed results.
For example, a 2007 study did not find an increased risk of heart disease in people with higher blood levels of phytosterols (
Additionally, a 12-week study of 232 people with high cholesterol found that consuming a low-fat spread with 3 grams of added phytosterols per day did not affect markers of circulatory health. (
On the flip side, several older studies have shown that increased levels of phytosterols in the blood may be linked to a higher risk of developing heart disease or having a heart attack (
One review also noted that some people have genetic variations in certain proteins that increase the absorption of phytosterols in the gut – and that having these proteins could be linked to an increased risk of heart disease (
Some studies suggest that phytosterols may increase plaque buildup in your blood vessels and may be linked to a higher risk of heart disease. However, more research is needed.
For centuries, phytosterols have been part of the human diet as a component of vegetables, fruits, legumes and other plant foods.
Today, they are added to some processed foods, including many types of margarine.
Studies show that a high intake of phytosterols may be associated with lowered cholesterol levels and a lower risk of certain types of cancer.
Yet research on their other potential effects on heart health, including their impact on plaque buildup and heart disease, has shown mixed results. So, more research is needed.
Ultimately, it’s best to increase your intake by enjoying plant foods that are more nutrient-dense rather than processed foods and supplements fortified with phytosterols.