Phytosterols are plant-derived sterols that resemble cholesterol in structure and function. They are found in various plant oils, nuts, seeds, and whole grains. Phytosterols play a significant role in human health by lowering cholesterol levels and improving heart health. They compete with cholesterol for absorption in the intestines, leading to reduced cholesterol levels in the bloodstream. Phytosterols are also known for their anti-inflammatory properties and potential benefits in reducing the risk of certain cancers. They are often added to functional foods and dietary supplements for their health-promoting effects.