Antioxidants protect against oxidative stress by neutralizing free radicals, which are unstable molecules that can damage cells. By donating electrons to these free radicals, antioxidants can prevent cellular damage, thereby reducing the risk of chronic diseases, including cancer and heart disease. They are crucial for maintaining cell health and supporting the body’s natural defense mechanisms. Common sources include fruits, vegetables, nuts, and seeds, all of which should be emphasized in a balanced diet.