Did You Know Just That Many Cancers Are Linked To A Vitamin Deficiency?
What are free radicals and how detrimental
are they to your health? You might be surprised to know
that much of the body's aging processes are caused by oxidation
of the body's cells, similarly to rust forming on exposed
iron. Certain antioxidant vitamins can help reduce the formation
of free radicals.
Free Radicals: How Vitamins Can Help
Free Radicals: How Vitamins Can Help
By: Dr. George Obikoya
A
free radical is a chemical "species" that contains
an unpaired electron. This is very bad to have in your body,
because it wants to achieve stability. The only way to do
that is to combine, or "react" with other molecules.
Unfortunately, usually those molecules are important things
like DNA or our cells. A few stable free radicals are known
but most are very reactive (they want to combine with other
molecules). In free radical chain reactions, the radical
product of one reaction becomes the starting material for
another, propagating free radical damage - think out of
control nuclear fission.
There
are three steps to free-radical chain reaction: initiation,
propagation, and termination. In the initiation step, free
radicals are formed from molecules that readily give up
electrons, such as hydrogen peroxide. In the propagation
steps, the chain-carrying radicals are alternately consumed
and produced. In the termination steps, radicals are destroyed.
Thus, without termination by an agent such as an antioxidant,
a single free radical can damage numerous molecules, including
your DNA.
There
are four common oxygen metabolites in our bodies that are
free radicals: superoxide anion (O2- ), hydrogen peroxide
(H2O2), hydroxyl radical (OH ), and singlet oxygen (1O2).
These free radicals can be generated via a number of mechanisms,
including normal physiologic processes and processes resulting
from other external factors such as damage to the body or
increased exercise.
For
example, singlet oxygen is generated by photosensitization
reactions wherein a molecule absorbs light of a given wavelength,
exciting the molecule. This excited molecule transfers the
increased energy to molecular oxygen, creating singlet oxygen,
which then can attack other cell components and start a
chain reaction.
It
appears that the primary function of carotenoids, an important
class of antioxidants, is to scavenge free radicals, particularly
singlet oxygen produced by photosensitization.
A certain amount of oxidative function is necessary for
proper health. For example, oxidation processes are used
by the body's immune systems to kill microorganisms. Sometimes,
however, the level of toxic reactive oxygen intermediates
(ROI) overcomes the antioxidant defenses of the host, resulting
in an excess of free radicals and a state called oxidative
stress. This process can be extremely damaging, as its effects
compound over time.
Free
radicals can induce local injury by reacting with lipids,
proteins, and nucleic acids (such as DNA). The interaction
of free radicals with cellular lipids leads to membrane
damage and the generation of lipid peroxide byproducts.
Interaction with nucleic acids leads to a breakdown of our
DNA and increased cellular death.
Cells
contain a number of antioxidants that have various roles
in protecting against free radical reactions. The major
water-soluble antioxidant metabolites are glutathione (GSH),
the B vitamins and vitamin C. Many water-soluble enzymes
also catalyze these reactions. Vitamin E and the carotenoids
are the principal lipid-soluble antioxidants. Vitamin E
is the major lipid-soluble antioxidant in cell membranes
that can break the chain of lipid peroxidation. Therefore,
it is the most important antioxidant in preventing oxidation
of these fatty acids. Vitamin E is recycled by a reaction
with vitamin C, so it is commonly suggested to take both
vitamins E and C together.
Despite
the actions of antioxidant nutrients, some oxidative damage
will occur, and accumulation of this damage throughout life
is believed to be a major contributing factor to aging and
disease. Fortunately, you can reduce the oxidative stress
on your cells with common, inexpensive vitamin supplements.
The
Institute of Medicine (IOM) recently updated nutritional
requirements for the antioxidant nutrients (vitamin C, vitamin
E, carotenoids, and selenium), as well as other nutrients.
In the past, Recommended Dietary Allowances (RDAs) were
used in the United States and Recommended Nutrient Intakes
(RNIs) were used in Canada. Since the last review of these
guidelines in 1989 and 1990, respectively, harmonized new
data have emerged reflecting dietary requirements of food
components and their role in maintaining health.
Reactive
oxygen species are some of the most dangerous by-product
of our breathing. Fortunately, antioxidants help clear our
body of reactive oxygen intermediates (ROI). Nutritional
antioxidants are believed to have potential treatment for
a wide variety of diseases, including cancer, atherosclerosis,
chronic inflammatory diseases, even aging. Take vitamins
E and C for example. Recent research shows that in combination,
these vitamins in combination were extremely effective at
lowering your risk of developing Alzheimer's disease.
An
antioxidant is a substance that in low concentrations relative
to the oxidizable substrate substantially delays or reduces
oxidation of the substrate . Antioxidants fight oxidation,
hence their name. They protect other chemicals in our body
from toxic oxidation reactions by reacting with free radicals
and other reactive oxygen species, essentially derailing
the oxidation process. In a way similar to how sunblock
works, the antioxidant (such as Vitamin E) sacrifices itself
by being oxidized during this reaction.
Because
your antioxidant supply is limited, as one antioxidant molecule
is only capable of reacting with one free radical, you need
to regularly replenish your antioxidant supplies via vitamin
supplementation. There are many antioxidants including vitamin
C, vitamin E, selenium, and the carotenoids and 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 that are all powerful
antioxidants.
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 fat soluble, so its antioxidant properties
are best used by fattier parts of the body such as the brain.
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 can protect
us against cancer, heart disease, and complications of diabetes.
The
only specific known purpose of carotenoids in humans is
to act as a source of vitamin A in the diet, but they also
have important antioxidant effects. 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 (eye) 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.
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.
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