Antioxidants are compounds that combat oxidative stress by neutralizing free radicals in the body, which can damage cells and lead to various health issues. Common antioxidants include vitamins C and E, selenium, and plant-based compounds like flavonoids and carotenoids. These compounds are important for preventing chronic diseases such as cancer and heart disease, and they help maintain a healthy immune system. Consuming a diet rich in fruits, vegetables, and whole foods ensures adequate antioxidant intake, promoting long-term health.