A growing body of research continues to highlight the benefits of plant-based eating—not just for weight control but for preventing chronic diseases. Now, a new study suggests that phytosterols, natural compounds found in plants, may help lower the risk of heart disease and type 2 diabetes.

Presented at the American Society for Nutrition’s conference, this study provides promising evidence that the foods we eat daily—particularly those rich in plant sterols—can have a measurable impact on our gut microbiome, cholesterol levels, and metabolic health.

What Are Phytosterols?

Phytosterols (also known as plant sterols) are naturally occurring compounds found in all plant-based foods. They share a similar chemical structure with cholesterol and compete with it in the digestive tract, reducing the amount your body absorbs.

You’ll find phytosterols in:

  • Fruits and vegetables (especially oranges, broccoli, avocados)

  • Legumes and nuts (almonds, walnuts, pistachios)

  • Whole grains (wheat germ, rye bread)

  • Unrefined seed oils (like sunflower, flaxseed, and soybean oils)

Some vegetable oils and nut oils—such as olive oil and canola oil—also contain high levels of these compounds.

The Study: How Phytosterols May Affect Disease Risk

Researchers led by Dr. Fenglei Wang at the Harvard T.H. Chan School of Public Health analyzed data from three large, long-term studies tracking over 206,000 people for up to 36 years.

The researchers assessed participants’:

  • Dietary intake of phytosterols

  • Blood biomarkers related to metabolism and inflammation

  • Gut microbiome composition (in a subset of 465 participants)

Rather than focusing on supplements, this study looked at the real-life benefits of phytosterols from food. Specifically, it examined the effects of the three main types of plant sterols:

  • β-sitosterol

  • Campesterol

  • Stigmasterol

The goal? To explore how these sterols may influence inflammation, insulin sensitivity, and other risk factors tied to chronic disease.

Findings: Plant-Based Diets Rich in Phytosterols May Lower Disease Risk

Compared to participants who consumed the least amount of phytosterols, those who consumed the most were:

  • 9% less likely to develop cardiovascular disease

  • 8% less likely to develop type 2 diabetes

People in the high-intake group ate a diet that included approximately:

  • 4–5 servings of vegetables daily

  • 2–3 servings of fruit

  • 2 servings of whole grains

  • ½ serving of nuts

Gut Microbiome Benefits

β-sitosterol—found in high amounts in vegetables like broccoli, cauliflower, and fruits like avocados and oranges—was most strongly linked with positive changes in gut bacteria.

According to Dr. Dariush Mozaffarian of Tufts University, this plant sterol appears to be metabolized in the gut into compounds that:

  • Promote the growth of short-chain fatty acid-producing bacteria, which are linked to better insulin sensitivity

  • Lower levels of TMAO (trimethylamine N-oxide), a compound created from red meat digestion and associated with increased heart disease risk

Why Phytosterols May Lower Cholesterol and Inflammation

Phytosterols are best known for their ability to lower LDL (“bad”) cholesterol. Because they resemble cholesterol in structure, they block its absorption in the intestines.

This is important because high LDL levels can contribute to plaque buildup in arteries, leading to atherosclerosis, heart attacks, or stroke. According to the CDC, about 10% of U.S. adults and 7% of youth have elevated cholesterol.

In addition to lowering LDL, plant sterols may also:

  • Reduce inflammation

  • Improve insulin resistance

  • Support a healthier gut microbiome

“Plant sterols are not just mechanical agents,” Mozaffarian noted. “They metabolize in the gut and produce beneficial metabolites that influence multiple systems in the body.”

Limitations: What This Study Does—and Doesn’t—Prove

While the study is compelling, there are several important caveats:

  • It was observational, meaning it only shows an association—not direct cause and effect.

  • Dietary data was self-reported via surveys, which can lead to recall bias.

  • Not all participants had gut microbiome or metabolite data, which may limit some of the conclusions.

Still, the research builds on decades of evidence suggesting that plant-heavy diets support metabolic and cardiovascular health.

Supplements vs. Whole Foods: Where Should You Get Phytosterols?

In clinical practice, phytosterol supplements are sometimes prescribed to help lower cholesterol. These typically contain around 2,000 mg of plant sterols per day.

By contrast, most people consume less than 600 mg daily from food. Despite the lower amount, this study showed that natural food sources still provide benefits—likely because they come packaged with fiber, vitamins, antioxidants, and other plant-based nutrients.

“As researchers, we always focus on increasing whole food intake,” Dr. Wang said. “Foods like fruits, vegetables, and whole grains not only provide phytosterols but offer a range of other benefits as well.”

How to Add More Phytosterols to Your Diet

You don’t need a supplement to reap the benefits of phytosterols. Instead, aim to eat more of the following foods:

Fruits and Vegetables

  • Broccoli, cauliflower, carrots, and leafy greens

  • Avocados, oranges, apples, and berries

Whole Grains and Seeds

  • Wheat germ, rye bread, oats

  • Flaxseed, sunflower seeds, pumpkin seeds

Nuts and Oils

  • Almonds, walnuts, pistachios

  • Olive oil, canola oil, sunflower oil

Sample Tips:

  • Add sliced avocado or nuts to salads

  • Use olive oil in cooking or as salad dressing

  • Swap white bread for whole grain or rye bread

  • Blend fruits and vegetables into smoothies

Final Thoughts: Plants for Prevention

The takeaway is clear: a plant-rich diet can help reduce your risk of heart disease and type 2 diabetes, and phytosterols may be one of the key players.

Though more research is needed to fully understand how these compounds work within the body, the evidence strongly supports what nutrition experts have said for years—eating more plant-based foods is one of the best ways to support long-term health.

So next time you plan your meals, remember: adding just a few more servings of vegetables, fruits, whole grains, and nuts  could make a big difference—not just for your cholesterol and blood sugar, but for your gut, your metabolism, and your heart.