A new study led by researchers at the Harvard T.H. Chan School of Public Health has found that eating more plant-based foods rich in natural compounds called phytosterols may reduce the risk of developing heart disease and type 2 diabetes.
The findings, to be presented at NUTRITION 2025 in Orlando, suggest that these plant compounds may improve health by helping the body regulate insulin, reduce inflammation, and support a healthier gut.
Phytosterols are plant-based compounds that are structurally similar to cholesterol. They’re found naturally in small amounts in foods like vegetables, fruits, nuts, and whole grains.
While earlier studies have shown that phytosterols can lower levels of LDL (or “bad”) cholesterol when taken in high doses—such as in fortified foods or supplements—this new research shows that even the smaller amounts found in a typical healthy diet can offer important health benefits.
Dr. Fenglei Wang, a research associate involved in the study, explained that the results add weight to the advice of following a healthy plant-based diet. “Our findings support the dietary recommendation of eating more vegetables, fruits, whole grains, and nuts,” said Wang. “These choices can help people make smart decisions to improve their long-term health.”
To investigate the role of phytosterols, Wang and his team analyzed data from more than 200,000 U.S. adults who participated in three long-term health studies. Most participants were women working as nurses or in other healthcare roles.
The study tracked their health over a period of up to 36 years, during which time over 20,000 people developed type 2 diabetes and nearly 16,000 developed heart disease.
Researchers used food questionnaires to estimate each participant’s intake of total phytosterols, as well as three common types: β-sitosterol, campesterol, and stigmasterol. Those who consumed the most phytosterols typically ate 4–5 servings of vegetables, 2–3 servings of fruit, two servings of whole grains, and a small amount of nuts each day.
Compared to those who consumed the least, they had a 9% lower risk of heart disease and an 8% lower risk of type 2 diabetes. These benefits were especially linked to β-sitosterol, the most common phytosterol in the diet.
The team also studied blood samples from tens of thousands of participants and found that higher phytosterol levels—especially β-sitosterol—were associated with healthier levels of key biological markers.
These markers indicated better insulin activity (how well the body processes sugar), less inflammation, and other signs of good metabolic health, all of which play a role in preventing heart disease and diabetes.
In addition, researchers explored how the gut microbiome—the community of bacteria living in the digestive tract—might be involved. In a smaller group of 465 people, they found certain gut bacteria that seemed to be more common in those who consumed more phytosterols.
One such species, Faecalibacterium prausnitzii, is known to support a healthy gut and reduce inflammation. Some of these bacteria also carry enzymes that can break down phytosterols, possibly helping the body use them more effectively.
While this study cannot prove that phytosterols directly cause better health—since it’s observational rather than experimental—the results are strong because they combine many kinds of evidence, from diet data to blood tests to gut bacteria analysis.
In short, the research suggests that the natural plant compounds found in everyday foods like fruits, vegetables, nuts, and whole grains could play a key role in preventing two of the most common chronic diseases in the U.S. Eating a variety of plant-based foods every day might not only help you feel better but also lower your long-term risk of serious health problems.
If you care about heart health, please read studies about top foods to love for a stronger heart, and why oranges may help fight obesity, diabetes, and heart disease.
For more health information, please see recent studies about simple guide to a 7-day diabetes meal plan, and why you should add black beans to your plate.
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