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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 ?
As of 2013, synthetic antioxidants held a larger share of the market than their natural counterpart.
The results of their work are promising for replacing synthetic antioxidants with natural antioxidants.
Likewise for skin care, getting caught up in the search for the “best” antioxidants almost certainly guarantees you won't end up using the best products.
Dubost adds that "not all antioxidants behave in the same way.
As people age, they have more free radicals in their body and fewer antioxidants.
They found that when you take antioxidants determines the safety and effectiveness of radiation.
According to the company, the line is enriched with antioxidants to help promote natural skin repair by neutralizing harmful free radicals created by ultraviolet (UV) exposure.
This may explain the interest in examining plant extracts as a source of cheaper and effective antioxidants and the growing interest in nutraceuticals.
A randomized controlled trial of antioxidant supplementation for pain relief in patients with chronic pancreatitis.
Offers Ethanox and Ethaphos primary and secondary antioxidants for use in a wide variety of polymers from thermoplastic elastomers and engineering blends/alloys to hot-melt adhesives and tackifiers, as well as polyolefins.
Another study report, "Dietary Intake of Antioxidants and Risk of Age-Related Macular Degeneration," was published in the Journal of the American Medical Association (December 28, 2005).