Phytosterols — natural plant compounds found in foods like nuts, whole grains, fruits and vegetables — might do more than just nudge down cholesterol levels. A new analysis suggests they could also reduce the risk of heart disease and type 2 diabetes by supporting healthier metabolism.
Researchers from the Harvard T.H. Chan School of Public Health examined dietary and health data from more than 200,000 U.S. adults over three decades. They found that people with the highest intake of phytosterols were 9% less likely to develop heart disease and 8% less likely to develop type 2 diabetes compared with those consuming the least.
“Our findings support the dietary recommendation of adhering to healthy plant-based dietary patterns that are rich in vegetables, fruits, nuts and whole grains,” said study author Fenglei Wang, PhD.
The study, presented at the American Society for Nutrition’s 2025 annual meeting, is among the first to link everyday dietary levels of phytosterols, not just supplements, to improved long-term health outcomes.
Researchers found that participants who consumed about four to five servings of vegetables, two to three servings of fruit, two servings of whole grains and half a serving of nuts per day had the highest phytosterol intakes. Those individuals also had better markers of insulin regulation and lower levels of inflammation.
“Our clinical biomarker and metabolomic results suggest the involvement of insulin activity, inflammation and the metabolism of metabolites associated with type 2 diabetes and cardiovascular disease,” Wang said.
In a subset of participants, the team also analyzed gut microbiome data and found that higher phytosterol intake was linked with microbial species, such as Faecalibacterium prausnitzii, that may help break down these compounds and promote metabolic health.
While the study was observational and cannot confirm cause and effect, the researchers say the consistency across diet, blood biomarkers and gut health adds strength to the findings.
This research was supported by the National Institutes of Health and the American Heart Association.