Plant Power: How Dietary Phytosterols Could Guard Against Heart Disease and Diabetes
Heart disease and type 2 diabetes remain formidable health challenges in the United States. While the benefits of a plant-rich diet for prevention are well-established, new research is shedding light on a specific plant compound, phytosterol, as a potential key player in lowering the risk of both conditions. A large-scale study suggests that individuals with higher dietary intake of phytosterols – compounds structurally similar to cholesterol found naturally in plant foods – demonstrated a significantly reduced risk of developing heart disease and type 2 diabetes.
Beyond disease prevention, the study also linked higher phytosterol consumption to improved markers of insulin regulation, reduced inflammation, and beneficial alterations in the gut microbiome, all of which contribute to healthy metabolism.
"Our findings support the dietary recommendation of adhering to healthy plant-based dietary patterns that are rich in vegetables, fruits, nuts and whole grains," stated Fenglei Wang, Ph.D., a research associate at the Harvard T.H. Chan School of Public Health. "These findings can help people make informed dietary choices." Dr. Wang is set to present these compelling findings at NUTRITION 2025, the annual meeting of the American Society for Nutrition.
While previous research has indicated that phytosterols can positively impact health by lowering "bad" LDL cholesterol, these studies often involved high, supplemental doses. This new research stands out as one of the first to demonstrate the benefits of phytosterols consumed as part of a regular diet. Dr. Wang and her team meticulously analyzed data from over 200,000 U.S. adults, primarily nurses and health professionals, with nearly 80% being women. Over a follow-up period spanning up to 36 years, more than 20,000 participants developed type 2 diabetes and nearly 16,000 were diagnosed with heart disease.
Using detailed food-frequency questionnaires, researchers estimated each participant's intake of total phytosterols and three specific types: β-sitosterol, campesterol, and stigmasterol. The participants with the highest phytosterol intake typically consumed a diet rich in plant foods, including about 4-5 servings of vegetables, 2-3 servings of fruit, two servings of whole grains, and half a serving of nuts daily.
Comparing the highest phytosterol consumers to those with the lowest intake revealed significant benefits: the top quintile was 9% less likely to develop heart disease and 8% less likely to develop type 2 diabetes. Notably, similar positive associations were observed specifically for β-sitosterol, but not for campesterol or stigmasterol, suggesting a more targeted effect for certain phytosterol types.
To delve deeper into the underlying mechanisms, the researchers analyzed blood samples from over 11,000 participants for metabolites (products of metabolism) and from over 40,000 participants for other metabolic biomarkers. Their findings indicated that total phytosterol and β-sitosterol were associated with favorable metabolic markers relevant to heart disease and diabetes. "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," explained Dr. Wang, adding that "This suggests that phytosterol might reduce risk by alleviating insulin resistance and inflammation."
Intriguingly, the study also explored the role of the gut microbiome in a subset of 465 participants. They identified several microbial species and enzymes associated with higher phytosterol intake that may influence the production of beneficial metabolites. "We found that the gut microbiome might play a role in the beneficial associations," Dr. Wang noted. "Some species, such as Faecalibacterium prausnitzii, carry enzymes that could help degrade phytosterol, potentially influencing host metabolism."
While acknowledging the observational nature of the study, which means it cannot definitively prove causation, the researchers emphasize that the convergence of epidemiological data, biomarker analysis, and microbiome insights significantly strengthens the evidence supporting the health benefits of dietary phytosterols. These findings reinforce the message that a diet abundant in plant-based foods is a powerful tool in the fight against two of the nation's most prevalent chronic diseases.
Source: American Society for Nutrition