Antioxidants are substances that protect your cells against the effects of free radicals. The body produces free radicals when it breaks down food or is exposed to harmful environmental factors such as radiation or tobacco smoke. Free radicals damage cells and may play a role in an increased risk for heart disease or cancer. Antioxidants can be found in many foods and include vitamin A, vitamin C, vitamin E, selenium and beta-carotene.
Vitamin A is found in eggs, butter, milk and liver. It helps with immune function, vision, reproduction and cellular communication. Vitamin A is a fat-soluble vitamin that also plays a role in healthy cell growth and formation and maintenance of the heart, lungs and kidneys. Forms of vitamin A include lycopene, lutein, zeaxanthin and beta-carotene.
Vitamin C is the most commonly known antioxidant and offers many benefits. It protects the body from infections and helps produce collagen, which is the connective tissue that holds bone and muscle together. It also protects the body from bruising by keeping capillary walls and blood vessels firm. Vitamin C also assists iron and folate absorption. Vitamin C is found in many fruits and vegetables including strawberries, oranges, tomatoes, bell peppers and cantaloupe.
Vitamin E is found in peanuts, Brazil nuts, almonds and oils such as sunflower, corn, soybeans and canola oils. Vitamin E protects against heart disease, cancer and cataracts, which may develop as one ages. It works with vitamin C to protect against other chronic diseases. Vitamin E is involved in immune function, regulation of gene expression and cell signaling.
Selenium is a trace mineral that is essential for health but is only required in a small amount. Selenium helps to regulate thyroid function and plays a role in the immune system. Selenium is found in cereal, nuts, beans, tuna, dairy products and meat. The amount of selenium found in foods depends on the amount of selenium contained in the soil, so crops grown in selenium-rich soil will have greater levels of this antioxidant.
Beta-carotene is found in red, orange and yellow foods such as carrots, apricots, mangoes, pumpkin, broccoli and sweet potatoes. It can also be found in some green leafy vegetables such as kale and spinach. There are actually more than 600 carotenoids in foods, which reduce the damage from free radicals. Carotenoid-rich foods are known to protect against prostate and other cancers. Beta-carotene can decrease asthma symptoms and also decrease the risk of heart disease, macular degeneration and cancer.
Amanda Hernandez is a registered dietitian who holds a Master of Arts degree in family and consumer sciences with an emphasis in dietetics from Western Michigan University. Her work has been featured in "Women's World" and "Women's Day" magazines. She writes for nutritionistreviews.com and has been a nutrition writer since 2010.