What Are Phytosterols?
Phytosterols—otherwise known as plant sterols, plant stanols, and sterol esters—are compounds found in the cell membranes of many plants you may already eat. Like cholesterol, phytosterols are a steroid, and the two have very similar chemical structures. But unlike cholesterol, phytosterols aren’t produced in the human body, which means we have to eat them to benefit from them.
More than 250 types of plant sterols have been discovered in plant species so far, and most plant species seem to boast their own, unique composition of them. Three sterols in particular are most abundant in many of the heart-healthy foods you may already enjoy:
Beta-sitosterol: The phytosterol that is most prominent in such dietary sources as nuts, seeds, legumes, vegetables, and olive oil Campesterol: The second most prominent in dietary sources, with high concentrations in pomegranates, grapefruits, cucumbers, and lemongrass Stigmasterol: The third most prominent phytosterol, with high concentrations in cruciferous vegetables, seeds, unpasteurized milk, soybeans, and nuts
Interestingly, on a chemical level, all three plant sterols share the same core structure as cholesterol. For the heart, this is good news.
When we consume nuts, fresh veggies and other plant products that contain them, phytosterols compete with cholesterol for absorption in the intestines. The excess cholesterol that is not absorbed is then eliminated from the body.In theory, by choosing to consume more fresh foods that contain phytosterols, we could help curtail our cholesterol levels and reduce our risk of heart disease.
Why Animal Cholesterol Is Bad
High contents of saturated fat in many processed animal products can raise blood pressure, increase LDL cholesterol in the body, and contribute to the development of atherosclerosis—the buildup of fatty plaques within blood vessels that can lead to heart disease.
There tends to be more saturated fat in fatty meats like bologna, hot dogs, bacon, and ground beef, as well as full-fat dairy products like ice cream, whole milk, and butter. Palm oil and coconut oil are also common sources of saturated fat. Consuming these products regularly can make it much harder to keep your LDL cholesterol low.
How Plant Sterols Impact Cholesterol Levels
The therapeutic properties of phytosterols have been demonstrated in numerous studies throughout the years, prompting the Food and Drug Administration to allow products containing phytosterols to be labeled as “heart-healthy” on their packaging.
The average person consumes about 300 milligrams (mg) of phytosterols throughout their day. Sustained at that amount, phytosterols aren’t able to reduce LDL cholesterol. However, encouraging evidence suggests that adding more phytosterols to our diets could reduce LDL cholesterol levels after just two to three weeks of keeping up with the diet.
In one 2020 study, 90 adults were selected to consume either a phytosterol-enriched spread or the same spread without phytosterols. Adults who consumed the phytosterol spread had between 9% to 12% lower LDL cholesterol levels after six months—a result that is consistent with past research. It was noted that mean cholesterol levels did not improve as much in adults who were overweight.
Studies also show that maintaining a phytosterol intake of at least 2 grams per day could lower your cholesterol between 8% and 10% for up to 85 weeks. The evidence that phytosterols may continue to lower LDL cholesterol after that is convincing, but more long-term studies are needed before we can prove eating them will actually prevent cardiovascular disease.
Foods Rich in Plant Sterols
According to the National Lipid Association, eating 2,000 mg of phytosterols each day may lower your LDL cholesterol by 5% to 10% and reduce your risk of heart disease. One banana has 16 mg of phytosterols per 100 mg serving, so you may need to include supplements to meet that recommended amount.
Phytosterols in Nuts
Nuts are integral to the heart-healthy Mediterranean diet, and consuming 23 to 132 grams (g) of nuts regularly is closely linked to a reduced risk of heart disease. Phytosterols—beta-sitosterol in particular—have been identified in at least nine different types of nuts:
But there is some contention about the safety and effectiveness of phytosterol supplements, particularly when compared to the biologically active properties found in natural sources. As they are extracted and purified during the manufacturing process, those therapeutic properties can deactivate, resulting in a loss of their effects.
Then again, there is some support for phytosterol supplementation. In one study, 38 adults were randomly assigned to drink either soymilk or soymilk supplemented with 1.6 g of phytosterols each day for four weeks. At the end of the trial, those who consumed phytosterol supplements had 6.4% less LDL cholesterol without any effect on their HDL cholesterol (the “good” cholesterol) levels.
What are phytosterols good for?
Phytosterols are a micronutrient found in plants that can help to lower LDL cholesterol.
What foods are high in phytosterols?
Unrefined plant oils—including vegetable, nut, and olive oils—are the foods with the highest concentration of phytosterols. Other good dietary sources of phytosterols are nuts, seeds, whole grains, and legumes.
What are the side effects of phytosterols?
Phytosterols found in food do not have any side effects. Taking phytosterol supplements can have mild gastrointestinal side effects including constipation, nausea, upset stomach, heartburn, gas, and discolored stools.
Are phytosterols safe?
Phytosterols found naturally in nuts, fruits, vegetables, legumes, grains, and oil are perfectly safe to consume. However, it may not be possible to get a therapeutic dose through diet alone. Supplements may help to fill the gap, but it’s unclear if they are safe or effective.
A Word From Verywell
A diet filled with phytosterols appears to lower LDL cholesterol and reduce the likelihood of atherosclerosis development in some healthy persons. However, the argument for supplementation has seen some pushback. So far, researchers have not found evidence that long-term consumption of phytosterols will prevent cardiovascular disease. If you’re concerned about your LDL cholesterol, visit your healthcare provider to rule out other conditions that could be the cause.
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