Plant-Based Foods Linked to Lower Diabetes and Heart Disease Risk

A new study has found that eating more plant-based oils, fruits, vegetables, and whole grains—foods rich in natural compounds called phytosterols—may significantly reduce the risk of developing type 2 diabetes and cardiovascular disease.

“This supports the long-standing recommendation to increase the amount of plant foods people eat,” said lead author Fenglei Wang, PhD, a research associate at the Harvard T.H. Chan School of Public Health.

Phytosterols, also known as plant sterols, are substances present in all plant foods, particularly in nuts, seeds, legumes, whole grains, and plant oils. Almonds, walnuts, pistachios, flaxseed, wheat germ, rye bread, unrefined plant oils, and olive oil are especially high in these compounds. Although some people take phytosterol supplements, the study focused on the impact of eating foods naturally rich in phytosterols.

The research, presented at the American Society for Nutrition’s conference in Orlando, examined how the three main types of plant sterols—β-sitosterol, campesterol, and stigmasterol—affect metabolic health. Using data from over 206,000 people followed for up to 36 years, researchers assessed participants’ diets, blood biomarkers, and even their gut microbiomes.

Results showed that individuals with the highest phytosterol intake—those who regularly 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 daily—were 9% less likely to develop cardiovascular disease and 8% less likely to develop type 2 diabetes compared to those with the lowest intake.

Of the phytosterols studied, β-sitosterol appeared to have the strongest effect, promoting beneficial changes in gut bacteria linked to a lower risk of type 2 diabetes. Experts believe β-sitosterol helps increase the number of gut bacteria that produce short-chain fatty acids, which are known to support metabolic health. It may also help reduce trimethylamine N-oxide (TMAO), a gut byproduct of red meat that is associated with a higher risk for heart disease.

While the study was observational and relies on self-reported dietary data, its findings reinforce what previous research has found: phytosterols can block the absorption of LDL, or “bad,” cholesterol in the gut and may have anti-inflammatory effects. This is important, as high cholesterol affects about 10% of American adults and 7% of young people, raising the risk of heart disease as cholesterol builds up in the arteries over time.

Health experts say that getting phytosterols from whole foods rather than supplements offers additional benefits, since plant-based foods also provide other valuable nutrients and compounds. Dietitian Julia Zumpano of the Cleveland Clinic, who was not involved in the study, notes that on average, people in the U.S. get less than 600 mg of phytosterols per day from food. Supplements used in previous LDL-lowering studies usually provided about 2,000 mg per day, but the latest findings show even lower amounts from a healthy diet are linked to disease prevention.

To maximize the benefits, experts recommend eating more foods typical of the Mediterranean diet, which is high in vegetables, fruits, whole grains, nuts, and plant oils. “As nutrition researchers, we always focus on increasing the consumption of foods because these foods—vegetables, fruits, whole grains—are not just rich in phytosterols but in other beneficial compounds, too,” Wang emphasized.

In summary, increasing the diversity and quantity of plant foods in your diet may improve metabolic health, reduce inflammation, support beneficial gut bacteria, and help protect against type 2 diabetes and heart disease.