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| Coffee and Antioxidants |
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Oxygen is essential to human life; without it, we cannot survive. However,
oxygen is also involved in toxic reactions and is therefore a threat to the well
being of all living things. Human beings can tolerate oxygen only because our
evolutionary ancestors developed powerful defence mechanisms that minimize its toxic
effects.
Unfortunately, our natural defences are imperfect; they limit the harm caused
by oxygen but do not eliminate it completely. There is some evidence that as the
years go by, oxygen-induced damage to body tissues may accumulate.This damage
has been suggested as a major contributor to ageing, and to many other
degenerative diseases of ageing, including cardiovascular disease, cancer, cataracts, the
age-related decline in the immune system and degenerative diseases of the nervous
system.
In recent times, researchers have made major strides in understanding the link
between oxygenated metabolites and human diseases. At the same time, they have
learned that it may be possible to prevent, postpone or limit the severity of
these diseases by enhancing the body's antioxidant defence mechanisms through
improved nutrition.
Oxidants and free radicals
Most of the potentially harmful effects of oxygen are believed to be due to
the formation and activity of reactive oxygen species acting as oxidants, that is,
compounds with a tendency to donate oxygen to other substances. Many reactive
oxygen species are free radicals, and many free radicals are unstable or highly
reactive. Reactive oxygen species are produced continuously in the human body as a
consequence of normal metabolic processes.
If free radicals are not inactivated, this can cause damage to the body's
cells and can have an effect on proteins, carbohydrates, lipids and nucleic acids.
Several of these effects have been implicated as the cause of degenerative
diseases. For example, destructive effects on proteins may play a role in the
development of cataracts, effects on DNA are involved in the development of cancers, and
effects on lipids are thought to contribute to atherosclerosis.
Defences against oxidants = antioxidants
The human body has several mechanisms for defence against free radicals and
other reactive oxygen species. The various defences are complimentary to one
another because they act on different oxidants.
One important line of defence is a system of enzymes that decrease the
concentration of the most harmful oxidants. Nutrition plays a key role in maintaining
the body's enzymatic defences against free radicals and several essential
minerals including selenium, copper, manganese and zinc are involved in the structure
or catalytic activity of these enzymes.
If the body does not have an adequate supply of these minerals, this may
result in enzymatic defences being impaired and this in turn could lead to the
development of disease.
A second line of defence is small-molecular-weight compounds which act as
antioxidants. Many of these are found in the diet, the best known being vitamin E,
vitamin C and carotenoids. Some foods also contain other antioxidant substances.
These foods include soya beans, green and black tea, coffee, red wine, rosemary,
sage and other spices, citrus and other fruit, onions and olives. Some of these
foods have no known nutritional function, but they are nevertheless important to
human health because of their antioxidant potency.
SUMMARY
Although much remains to be learned, there is convincing evidence for the
involvement of free radicals in a number of diseases that constitute major public
health problems throughout the world. The evidence implicating them as being
causal in the development of cancer, atherosclerotic cardiovascular disease,
neurological disease and cataracts is especially strong.
Antioxidants may be of great benefit in improving the quality of life by
preventing or postponing the onset of degenerative diseases.
The human body has a complex system of its own natural antioxidant defences
that counteract the harmful effects of free radicals and other oxidants.
However, protection against free radicals can be enhanced by ample intakes of
dietary antioxidants, and this includes drinking coffee
For further information, visit References
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