Antioxidant is a catchall term for any compound that can counteract unstable molecules such as free radicals that damage DNA, cell membranes, and other parts of cells.
Your body cells naturally produce plenty of antioxidants to put on patrol. The foods you eat—and, perhaps, some of the supplements you take—are another source of antioxidant compounds. Carotenoids (such as lycopene in tomatoes and lutein in kale) and flavonoids (such as anthocyanins in blueberries, quercetin in apples and onions, and catechins in green tea) are antioxidants. The vitamins C and E and the mineral selenium also have antioxidant properties.
Why free radicals may be harmful
Free radicals are a natural byproduct of energy metabolism and are also generated by ultraviolet rays, tobacco smoke, and air pollution. They lack a full complement of electrons, which makes them unstable, so they steal electrons from other molecules, damaging those molecules in the process.
Free radicals have a well-deserved reputation for causing cellular damage. But they can be helpful, too. When immune system cells muster to fight intruders, the oxygen they use spins off an army of free radicals that destroys viruses, bacteria, and damaged body cells in an oxidative burst. Vitamin C can then disarm the free radicals.
How antioxidants may help
Antioxidants are able to neutralize marauders such as free radicals by giving up some of their own electrons. When a vitamin C or E molecule makes this sacrifice, it may allow a crucial protein, gene, or cell membrane to escape damage. This helps break a chain reaction that can affect many other cells.
It is important to recognize that the term “antioxidant” reflects a chemical property rather than a specific nutritional property. Each of the nutrients that has antioxidant properties also has numerous other aspects and should be considered individually. The context is also important—in some settings, for example, vitamin C is an antioxidant, and in others it can be a pro-oxidant.
Sources of antioxidants
Plant foods are rich sources of antioxidants. They are most abundant in fruits and vegetables, as well as other foods including nuts, whole grains, and some meats, poultry, and fish.
Good sources of specific antioxidants include:
- allium sulfur compounds – leeks, onions and garlic
- anthocyanins – eggplant, grapes, and berries
- beta-carotene – pumpkin, mangoes, apricots, carrots, spinach, and parsley
- catechins – red wine and tea
- copper – seafood, lean meat, milk and nuts
- cryptoxanthins – red capsicum, pumpkin, and mangoes
- flavonoids – tea, green tea, citrus fruits, red wine, onion, and apples
- indoles – cruciferous vegetables such as broccoli, cabbage, and cauliflower
- isoflavonoids – soybeans, tofu, lentils, peas, and milk
- lignans – sesame seeds, bran, whole grains and vegetables
- lutein – green, leafy vegetables like spinach, and corn
- lycopene – tomatoes, pink grapefruit, and watermelon
- manganese – seafood, lean meat, milk and nuts
- polyphenols – thyme and oregano
- selenium – seafood, offal, lean meat, and whole grains
- vitamin A – liver, sweet potatoes, carrots, milk, and egg yolks
- vitamin C – oranges, blackcurrants, kiwifruit, mangoes, broccoli, spinach, capsicum, and strawberries
- vitamin E – vegetable oils (such as wheat germ oil), avocados, nuts, seeds, and whole grains
- zinc – seafood, lean meat, milk and nuts
- zoochemical – red meat, offal, and fish. Also derived from the plants that animals eat.
Words to the wise
Articles and advertisements have touted antioxidants as a way to help slow aging, fend off heart disease, improve flagging vision, and curb cancer. And laboratory studies and many large-scale observational trials (the type that query people about their eating habits and supplement use and then track their disease patterns) have noted benefits from diets rich in certain antioxidants and, in some cases, from antioxidant supplements.
But results from randomized controlled trials (in which people are assigned to take specific nutrients or a placebo) have failed to back up many of these claims. One study that pooled results from 68 randomized trials with over 230,000 participants found that people who were given vitamin E, beta carotene, and vitamin A had a higher risk of death than those who took a placebo. There appeared to be no effect from vitamin C pills and a small reduction in mortality from selenium, but further research on these nutrients is needed.
These findings suggest a little overall benefit of the antioxidants in pill form. On the other hand, many studies show that people who consume higher levels of these antioxidants in food have a lower risk of many diseases.
Hope this article is Helpful 🙂 🙂