Did You Know Just That Many Cancers Are Linked To A Vitamin Deficiency?
Antioxidant vitamins help to prevent
cellular oxidation, which results in a breaking down of
cells, premature cellular death and may result in diseases
such as cancer. Not every vitamin is an antioxidant, but
lets explore the ones that are and how greatly beneficial
they are at warding off diseases and free radicals.
Antioxidant Properties of Vitamins
Antioxidant Properties of Vitamins
By: Dr. George Obikoya
A
dietary antioxidant is a substance (commonly found in foods)
that significantly decreases the harmful effects of "reactive
species", such as reactive oxygen and nitrogen molecules,
that disrupt normal physiological function on a cellular
level in humans.
Examples
include the antioxidant nutrients vitamin C, vitamin E,
selenium, and the carotenoids. A multitude of other nutrients,
including minerals such as copper, manganese, and zinc,
flavonoids (such as grape seed extract and phenols found
in green tea), and coenzyme Q10, also possess antioxidant
properties.
The
primary function of vitamin C (ascorbic acid) is the production
of collagen, which forms the basis for connective tissue
in bones, teeth, and cartilage. It also plays an important
role in wound healing, immunity, and the nervous system,
and acts as a water-soluble antioxidant.
Because
vitamin C is water soluble, its antioxidant functions take
place in aqueous body compartments. It also helps protect
low-density lipoprotein cholesterol (LDL-C) against free
radical damage. As an antioxidant, it helps protect against
cancer, cardiovascular disease, and certain effects of aging.
Vitamin
E is the name given to a group of eight fat-soluble compounds.
Unlike other vitamins, which are involved in metabolic reactions,
it appears that the primary role of vitamin E is to act
as an antioxidant. Vitamin E is incorporated into the lipid
portion of cell membranes and other molecules, protecting
these structures from oxidative damage and preventing the
propagation of lipid peroxidation. Vitamin E appears to
have protective effects against cancer, heart disease, and
complications of diabetes.
As
an antioxidant, vitamin E plays a protective role in many
organs and systems. Vitamin E is necessary for maintaining
a healthy immune system, and it protects the thymus and
circulating white blood cells from oxidative damage. Also,
it may work synergistically with vitamin C in enhancing
immune function. Recent research evidence indicates that
the combined use of high doses of vitamin C and vitamin
E helps prevent Alzheimer’s disease. In the eyes, vitamin
E is needed for the development of the retina and protects
against cataracts and macular degeneration.
Vitamin
E deficiency is rare, and occurs mostly in people with chronic
liver disease and fat malabsorption syndromes, such as celiac
disease and cystic fibrosis. It can lead to nerve damage,
lethargy, apathy, inability to concentrate, staggering gait,
low thyroid hormone levels, decreased immune response, and
anemia. Marginal vitamin E deficiency may be much more common
and has been linked to an increased risk of cardiovascular
disease and cancer.
The
only specific effect of carotenoids in humans is to act
as a source of vitamin A in the diet, but they also have
important antioxidant actions. The latter are based on the
caretenoids' ability to quench singlet oxygen and trap peroxyl
radicals, thereby preventing lipid peroxidation.
As
a result, carotenoids protect against the development of
cancer, cardiovascular disease, and ocular disorders. Carotenoids
also affect cell growth regulation and gene expression.
Diets low in carotenoids may lead to increased risk of cancer
and heart disease. Lycopene is the most potent antioxidant
for quenching single oxygen and scavenging free radicals.
Antioxidant
nutrients are often thought of as enhancing immune function.
Vitamin C, in particular, is generally perceived as useful
in the prevention and treatment of the common cold. Some
evidence does support a role of vitamin C, vitamin E, and
carotenoids in enhancing immunity.
Vitamin
C has been found to affect the human immune response, with
increased antimicrobial and natural killer cell activities,
lymphocyte proliferation, chemotaxis, and delayed dermal
sensitivity. Studies have involved pharmacologic doses of
vitamin C (200 mg/day to 6 grams/day in addition to dietary
intake); therefore, the effect does not appear to apply
to nutritional intake of vitamin C from food alone.
There
has been much interest in the use of pharmacologic doses
of vitamin C to prevent or treat the common cold, and some
studies have reported beneficial results. Treatment of the
common cold with vitamin C is associated with reduced duration
of cold symptoms. Several studies have found a protective
effect against breast cancer with beta-carotene.
Because
of the widespread effects of oxidation in the body, it is
possible that antioxidants protect against a wide array
of other ailments, such as certain respiratory disorders.
Asthma is characterized by chronic airway inflammation.
The generation of oxygen free radicals by activated inflammatory
cells produces many of the pathophysiologic changes associated
with asthma and may contribute to its pathogenesis. Therefore,
antioxidant nutrients may play a role in the prevention
and treatment of asthma.
Vitamin
C is the major antioxidant present in the surface of the
lung, suggesting a protective antioxidant role. A number
of studies support the use of vitamin C in allergy and asthma.
Of
all the chronic diseases in which excess oxidative stress
has been implicated, cardiovascular disease (CVD) has the
strongest supporting evidence for the beneficial role of
antioxidants. Oxidation of LDL-C may be a key step in the
development of atherosclerosis, and atherosclerosis and
hypertension are known risk factors in the development of
CVD. Thus, antioxidants are potentially useful in preventing
or delaying the development of atherosclerosis, and in preventing
heart disease.
A
good multivitamin is the foundation of health and nutrition.
Take a look at our scientific reviews of many of the popular
brands for factors such as ingredients, areas of improvement,
quality level, and overall value. If you are looking for
a high quality liquid multivitamin, we suggest that you
take a look at the Multivitamin Product Comparisons
References
Adams AK, Wermuth EO, McBride PE. Antioxidant vitamins and
the prevention of coronary heart disease. Am Fam Physician.
1999;60:895-904.
Padayatty
SJ, Levine M. Vitamin C and myocardial infarction: the heart
of the matter. Am J Clin Nutr. 2000;71:1027-8. Sinatra ST.
"Care," cancer and coenzyme Q10. J Am Coll Cardiol.
1999;33:897-8.
Tekin
D, Sin BA, Mungan D, et al. The antioxidative defense in
asthma. J Asthma. 2000;37:59-63.
Hatch
GE. Asthma, inhaled oxidants, and dietary antioxidants.
Am J Clin Nutr. 1995;61:625S-630S.
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