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Substances that inhibit oxidative changes in molecules. Many oxidative changes are destructive and this applies as much to the human body as to non-biological chemistry. Recognition that many of the fundamentally damaging processes in disease are oxidative in nature and result from the action of oxygen FREE RADICALS has raised interest in the possibility of using antioxidants to minimize such damage. The most popular choice for this purpose are the antioxidant vitamins C and E. There is evidence that, taken in adequate dosage, these vitamins act synergistically to reduce free radical effects. See also FLAVONOIDS and FRENCH PARADOX.


Substances that reduce the damage of the highly reactive free radicals that are the byproducts of the cells.


defend body cells against oxidative stress. Increased cellular concentrations of antioxidants have been claimed to diminish exercise-induced muscle damage, thus reducing the risk of cellular injury. The endogenous antioxidant enzymes are superoxide dismutase, catalase, glutathione peroxidase, glutathione S-transferase and glutathione reductase; ageing is known to reduce, and exercise training to elevate, their activities. The hormone melatonin, secreted by the pineal gland, has antioxidant properties and there is evidence that it promotes the action of antioxidant enzymes. antioxidant nutrients are vitamins A, C and E, and lipoic acid; supplementation with these has been demonstrated to protect against exercise-induced oxidative stress and sometimes from delayed onset of muscle damage, but most studies show no effect on physical performance. Some antioxidants (e.g. vitamins E and A, coenzyme Q10, carotenoids) are fat soluble and located within cell membranes; others such as vitamin C are water soluble, located in the cytosol, mitochondrial matrix or extracellular fluids. See also reactive oxygen species, vitamins.

antioxidants, substances that protect the body from free radicals and reactive oxygen species by converting the free radicals into more stable substances.

antioxidants, agents that reduce or prevent oxidation, such as occurs in the deterioration of fats, oils, and nonprecious metals.

Patient discussion about antioxidants

Q. What are “antioxidants”? and what do they do? I’ve been hearing about antioxidants for quite some time now, they are supposedly help to keep us younger. What do they do and is it true?

A. When every biological system works- it creates oxidants. These are materials that are very active and they “look for” something to react with. So when you eat (an example) there are a lot of oxidants created. they move around in the colon and they usually react with colon cells, thus destroying them. This also happens while breathing, cell metabolism and a lot of biological processes. Antioxidants counteract these free oxidants and stop their harmful reaction.

More discussions about antioxidants
References in periodicals archive ?
Herbs and spices such as ginger, rosemary, and turmeric are packed with antioxidants.
Moreover, researchers have found that the antioxidants in artichoke leaf are not broken down by gut microbes or by liver enzymes, boosting their benefits for the body.
Antioxidant manufacturers should look toward market penetration strategies in untapped emerging regions that have an expanding population with growing disposable income and high demand for ready-to-eat and frozen food products, observed Ramesh.
Accordingly, data from these assays should not be used to imply that compounds with high free radical scavenging capacities are good antioxidants in food systems.
The pear juice with plant extracts had higher antioxidant values than the pear juice that contained synthetic antioxidants.
It's possible that individual antioxidants, or the main foods that contribute those antioxidants-rather than the total antioxidant level in the diet-contribute to the lower risk of dementia and stroke found in earlier studies," she noted.
Antioxidants + Repair: Look for silky serums that contain a range of skin-repairing antioxidants, such as vitamin C, green tea, and caffeic acid.
Green and yellow antioxidants like lutein and zeaxanthin are linked to reducing the risk of atherosderosis--or hardening of the arteries and cataracts.
Free radicals are destroyed by antioxidants, so the body is defended by having a higher presence of antioxidants than free radicals.
Caffeine, although not a polyphenol, is believed to play a key complementary role in boosting the antioxidant performance of other antioxidants such as green tea and cocoa seed extract.
They found that when you take antioxidants determines the safety and effectiveness of radiation.
This may explain the interest in examining plant extracts as a source of cheaper and effective antioxidants and the growing interest in nutraceuticals.