What are Phytosterols?
Phytosterols are also known as plant sterols and are found naturally in many plants. They are the key structural components of cell membranes.(1) They are a family of molecules related to cholesterol.
The most commonly derived phytosterols are campesterol, beta-sitosterol, and stigmasterol. These are found commonly in nuts, seeds, and vegetables and are also added to processed foods like margarine.
Phytosterols block cholesterol absorption and are known to improve heart health and decrease blood LDL cholesterol.(2)
It is estimated that only 2 % of phytosterols found in the food is absorbed by the body. Compared with 50% of cholesterol.
Food Sources of Phytosterols
There are many plant foods that contain phytosterols in considerable amounts. These include:
- Nuts like almonds, cashews, macadamia, pistachios, and peanuts
- Fruits such as pineapples, oranges, berries, apples, banana, and apricots
- Seeds such as pumpkin seeds, watermelon seed, and sunflower seeds
- Legumes such as chickpeas, lentils, soybean, mung beans, and adzuki beans
- Oils like olive oil, sunflower oil, and canola oil.
People who eat vegan or vegetarian diets consume more phytosterols than people with a non-vegetarian diet.(3)
Phytosterols are obtained from plants foods, and many get added phytosterols from refined vegetable oils and processed foods like margarine.
Cereal grains also contain some phytosterols, making them a good source for people who eat a lot of grains.(4)
It is good to eat more whole grains that contain phytosterols so that other nutrients are also obtained.
Health Benefits of Phytosterols
Phytosterols offer several health benefits.
Reduce Cholesterol Level
Phytosterols contain more enzymes for their metabolism compared with dietary cholesterol.
According to a review, 2 grams of phytosterol in a day is able to reduce around 8-10 percent of LDL cholesterol.(5) However, the study used high-dose supplements and not natural food sources.
This makes phytosterols useful for people with high cholesterol. It also boosts the effectiveness of statins, a type of cholesterol-lowering medication.(6)
Lowers the Risk of Certain Cancers
A few evidence claim, phytosterol to have cancer-lowering properties.
There are various test tubes and animal studies showing the cancer-fighting properties of phytosterols. They also show their role in slowing down the spread of tumors.(10)
Most of the studies conducted are done on animals and more human research is needed to determine the effect of phytosterol on cancer growth in humans.
Downsides of Phytosterols
Phytosterols surely are known for their numerous benefits, but there are a few downsides to them.
Increases Plaque Build-up
Atherosclerosis narrows the arteries and makes it difficult for the heart to pump blood throughout the body.(12)
Increases the Risk of Heart Diseases
Phytosterols might decrease the level of LDL cholesterol, but studies proving their effectiveness in reducing the risk of heart disease has mixed result.
A study performed in 2007 found an increased risk of heart disease in people with high phytosterol levels.(13)
One more review noted that people with genetic variation in certain proteins had an increase in the absorption of phytosterols in the gut which could be linked to having an increased risk of heart disease.
Phytosterols have been a part of the human diet for since long. It can be found in fruits, legumes, and plant food. It is also added to some processed foods including margarine. It has numerous benefits and also a few downsides linked to it. It is, therefore, best to enjoy phytosterol-rich plant food rather than adding processed foods that are enriched with phytosterols and supplements.