Antioxidants are compounds that protect the body from oxidative stress caused by free radicals, which can lead to cellular damage and contribute to chronic diseases. Important antioxidants include vitamins C and E, selenium, and various phytonutrients found in fruits and vegetables. They play a vital role in supporting immune function, reducing inflammation, and promoting overall health. Regular consumption of antioxidant-rich foods can help lower the risk of conditions like heart disease, cancer, and neurodegenerative disorders, reinforcing their significance in a well-rounded diet.