A new study suggests that a natural compound found in plant foods—called phytosterol—may help lower the risk of heart disease and type 2 diabetes, two of the leading causes of death and long-term illness in the United States.
This compound, which is similar in structure to cholesterol, is found in foods like vegetables, fruits, whole grains, and nuts.
The research, led by Dr. Fenglei Wang from the Harvard T.H. Chan School of Public Health, found that people who ate more foods containing phytosterol were less likely to develop heart disease or type 2 diabetes.
These individuals also had better insulin control, lower inflammation levels, and a healthier balance of gut bacteria. The findings were presented at NUTRITION 2025, a major nutrition science conference.
While earlier studies showed that phytosterols can lower LDL cholesterol—the so-called “bad” cholesterol—those results were mostly based on supplements or high doses not normally achieved through diet. What makes this study important is that it looked at how eating a regular, plant-rich diet with natural levels of phytosterol affects long-term health.
The researchers analyzed health data from more than 200,000 U.S. adults, mostly nurses and health workers, followed over a period of up to 36 years. During that time, over 20,000 people developed type 2 diabetes and almost 16,000 developed heart disease.
Using diet questionnaires, the researchers estimated how much phytosterol each person consumed. They focused on total phytosterol as well as three specific types: β-sitosterol, campesterol, and stigmasterol.
Those who consumed the most phytosterols—meaning they regularly ate at least 4–5 servings of vegetables, 2–3 servings of fruit, two servings of whole grains, and half a serving of nuts per day—had about a 9% lower risk of heart disease and 8% lower risk of type 2 diabetes than those who ate the least.
Among the individual phytosterols studied, β-sitosterol seemed to provide the strongest benefit. The other two forms, campesterol and stigmasterol, did not show the same consistent effects.
To understand why phytosterol might offer these health benefits, the team looked at blood samples from over 11,000 people. They found that higher phytosterol levels were linked to healthier metabolic markers—things in the blood that indicate how well the body is managing fats, sugar, and inflammation.
These changes suggest that phytosterols may help the body respond better to insulin and reduce low-grade inflammation, both of which are key factors in preventing diabetes and heart problems.
The researchers also studied the gut microbiome—the trillions of bacteria in our digestive system that play a role in digestion and overall health. In a smaller group of 465 participants, they found that people who ate more phytosterols had more beneficial gut bacteria, such as Faecalibacterium prausnitzii.
These microbes may help break down phytosterols and produce helpful compounds that support metabolism and reduce disease risk.
While this was an observational study—meaning it shows links but doesn’t prove cause and effect—the results are supported by different kinds of data: long-term health tracking, blood tests, and gut bacteria analysis. Taken together, this builds a stronger case for the role of phytosterol in protecting against chronic disease.
The takeaway is simple: eating more plant-based foods rich in phytosterols—like leafy greens, whole grains, fruits, and nuts—can support your heart and metabolic health.
These foods are widely available, relatively affordable, and come with many other nutrients that support overall wellness. While supplements may help some people, this study shows that even normal dietary levels of phytosterols can make a difference over time.
In short, swapping out processed foods for more whole, plant-based options doesn’t just help your waistline—it could also help prevent serious diseases like diabetes and heart problems, especially when done consistently over the long term.
If you care about heart disease, please read studies that herbal supplements could harm your heart rhythm, and how eating eggs can help reduce heart disease risk.
For more health information, please see recent studies that apple juice could benefit your heart health, and results showing yogurt may help lower the death risks in heart disease.
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