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What Are Antioxidants and What Do They Do in the Body?


Antioxidant benefits and claims cover labels all over grocery stores, but how do they work and where are they naturally found? Antioxidants consist of some vitamins, minerals, carotenoids and polyphenols that are found in a variety of foods. Vitamin C, Vitamin E, beta carotene, carotenoids, some phytonutrients and some enzymes containing trace minerals (zinc, selenium, copper and manganese) are all considered antioxidants. They are associated with slowing or preventing oxidative stress and repairing damage to your cells. Additionally there is some evidence that they may improve immune function and reduce your risk for cancer or infections.

Oxygen is constantly needed by every cell in your body to produce energy. Oxygen is burned by cells producing bi-products called free radicals. Free radicals are molecules that are missing an electron, thereby making them unstable and potentially damaging to DNA, body tissues and cells. To become stable, free radicals steal electrons from body cells, which can result in cell dysfunction and health problems like heart disease, cataracts, diabetes, cancer, Alzheimer's disease, deterioration associated with aging and other health-related issues. Free radicals can also be formed from negative environmental factors like UV light and cigarette smoke. You can see this reaction even in foods like when you cut an apple and the slices turn brown due to the oxidation -- but when you dip it in lemon juice, it stays white!

Antioxidants work by giving free radicals an electron and thereby converting them into waste products that can be eliminated from the body without doing any damage. Antioxidants can even repair some of the damage already done. All the different antioxidants synergistically work together, so a deficiency in one can hinder the effectiveness of the others. Some of the most well-known are vitamin C, vitamin E and carotenoids/beta carotene, which are precursors for vitamin A.

Vitamin C

Vitamin C, also known as Ascorbic Acid, is a water-soluble vitamin that helps form the connective tissue that holds your bones, muscles and tissues together and makes your capillary and blood vessels strong. It also works to enable your body to better absorb plant sources of iron and folate for the body to utilize. Additionally, it also can help fight infections, support your immune system and help wounds heal. Vitamin C is special because it is a water-soluble vitamin and attacks free radicals that are in the body fluids, not just in fat tissue. But because it is not stored in fat, you need to consume foods rich in vitamin C daily.

Some claims of vitamin C have been overstated. Evidence does not support taking large doses of vitamin C to prevent or treat colds or boost immunity. Vitamin C may have a mild antihistamine effect, thereby shortening the lengths of a cold and making some of the symptoms milder, but more research needs to be done. As with all vitamins, minerals and phytonutrients, food sources are the best for your body. Be careful not to over supplement, as research has not proven the efficacy and in some cases there can be detrimental side effects. Vitamin C-rich foods include bell peppers, guava, papaya, oranges, broccoli, grapefruit, mangos, cantaloupe, cabbage and collard greens. Citrus fruits and colorful fruits and vegetables are good sources.

Vitamin E

Vitamin E is another antioxidant that does more than just fight the effects of oxidation and free radical damage! This fat-soluble vitamin may help lower your risk heart disease, stroke and other health problems. It helps protect vitamin A, essential fatty acids and LDL cholesterol from being oxidized. The natural form of vitamin E found in vegetable oils, nuts and sunflower seeds, soy, spinach and peanut butter is better absorbed than synthetic forms found in supplements. When cooking with vegetable oils, be sure to not overheat the oil, or vitamin E will be destroyed. Vitamin E protects the unsaturated fats in oils, nuts and seeds from being oxidized.

Carotenoids, Beta Carotene and Vitamin A

Beta Carotene is just one of more than 600 different carotenoids, which are all precursors to vitamin A. As with other antioxidants, carotenoids offer protection from diseases and degenerative changes associated with aging. They help maintain normal vision and the ability to see in the dark, as well as keeping your skin and tissues healthy from infections. By supporting your immune system, these antioxidants may help reduce the risk of cancer and promote the growth and well-being of cells and tissues in your body. They are considered essential in development of embryo and reproductive cells. Vitamin A is a fat-soluble vitamin, which can have many adverse reactions if excessively supplemented. Dietary sources are okay because your body slows its conversion of carotenoids to vitamin A once the body has stored enough.

Think bright colors when you think of carotenoids. The best sources are found in red, yellow, orange and dark-green leafy vegetables. Vitamin A can also be found in animal sources like fish oil, eggs and liver.

Antioxidants are beneficial to your health. Consuming bright colored foods can help you slow the aging process, protect your cells from damage and prevent diseases. Choose a variety of fruits, vegetables, nuts and seeds to ensure your diet is full of antioxidants and minimize supplementation because it has not been proven to be beneficial.


Emily DeLacey MS, RD is a Registered Dietitian and currently working in Jamaica as a HIV/ AIDS Prevention Specialist. She attended Central Washington University for her Bachelor's Degree in Science and Dietetics and continued on after her internship to Kent State University for her Master's Degree in Science and Nutrition, with a focus on public health and advocacy. She served as a U.S. Peace Corps Volunteer in Malawi 2012-2014 working as a Community Health Advisor in a rural village, immersing in the joys of life without electricity or running water. She has been to 20+ countries and 47 of the 50 states in the US. Traveling, adventuring and experiencing new cultures has made her a passionate advocate for the equality of nutrition and wellness for all people.

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