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Nutrition
News.....
ANTIOXIDANTS - FUNCTION, BENEFITS, SOURCES
AND SAFETY
PART I
Antioxidants - What are they?
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Oxidation is a natural process that
happens to all cells in nature,
including the cells in your body.
Antioxidants provide an important
defense against the daily assault of
free radicals on healthy cells. This
Essentials of Health four-part
series will review the function,
benefits, sources, and safety of
dietary antioxidants. |
Free radicals are atoms or groups of atoms
with an odd (unpaired) number of electrons
and can be formed when oxygen interacts with
certain molecules. Once formed these highly
reactive radicals can start a chain
reaction, like dominoes. Their chief danger
comes from the damage they can do when they
react with important cellular components
such as DNA, or the cell membrane. Cells may
function poorly or die if this occurs. To
prevent free radical damage the body has a
defense system of antioxidants.
Antioxidants are molecules that can safely
interact with free radicals and terminate
the chain reaction before vital tissues and
cells are damaged. Although there are
several enzyme systems within the body that
scavenge free radicals, the principle
micronutrient (vitamin/mineral) antioxidants
are vitamin E, beta-carotene, vitamin C and
selenium. The body cannot manufacture these
micronutrients so they must be supplied in
the diet. In addition, there are literally
hundreds of plant derived nutrients (phytonutrients)
that act as important antioxidants in the
diet.
It is impossible to avoid damage by free
radicals. Free radicals arise from sources
both inside (endogenous) and outside
(exogenous) our bodies. Oxidants that
develop from processes within our bodies
form as a result of normal breathing,
metabolism, and inflammation. Exogenous free
radicals form from environmental factors
such as pollution, sunlight, strenuous
exercise, X-rays, smoking and alcohol. Our
antioxidant systems are not perfect, so as
we age, cell parts damaged by oxidation
accumulate.
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