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Vitamin C
 The
RDA for Vitamin C
was also increased by the NAS. The new RDA
has been increased by 30% for men to 90 mg per day, and by 16% for women to
75 mg per day. Smokers need an additional 35 mg per day. For the first time,
maximum levels for Vitamin C have also been set. For adults, the upper level
of Vitamin C is 2,000 mg per day.
Dr. Linus Pauling , two times Nobel Laureate and "father of Vitamin C", postulated
the benefits and promoted high intakes of Vitamin C for decades. As early as
the late 1960s, he started taking 2,000-3,000 mg of Vitamin C a day. Dr. Pauling
was way ahead of his times. As the years went by, he increased his Vitamin C
intake progressively until the early 1990s, in the latter years of his life,
when he was taking as much as 18,000 mg a day. He died at the age of 93 and
attributed the last 12 years of his life to his high Vitamin C intake.
To have a better understanding of Dr. Pauling's hypothesis concerning the benefits
of antioxidants, it is helpful to have an understanding of free radicals.
Primer on
Free Radicals and Antioxidants
Molecules are composed of atoms and atoms are composed of a nucleus surrounded
by an orbit of electrons. In a stable molecule, these electrons orbit their
respective nuclei in pairs. When a reaction occurs causing a molecule to
either loose an electron, or gain an extra electron, the result is a molecule
with an unpaired electron. This molecule is called a free radical. It is highly
reactive, meaning it will try to combine with other molecules in order to steal
an electron, so it can return to a stable state. The molecule from which
the original free radical steals the electron becomes a free radical, wanting
to steal an electron, resulting in a domino effect or a self-perpetuating process.
Many of our body's normal metabolic processes produce free radicals. For
example, free radicals are a normal by-product in the production of ATP (the
energy molecule) from glucose. In another case, our body produces free radicals
on an ongoing basis. Certain types white blood cells are able to destroy
invading microbes by the production of free radicals. Free radicals are also
formed by enzymatic production. However, external sources such as pollution,
cigarette smoke and sunlight can also result in the formation of free radicals.
Excessive production free radicals can cause damage. Fats, protein, carbohydrates,
and DNA are all subject to free radical damage. Membranes exposed to free
radicals lose their ability to properly transport nutrients, lipoproteins are
changed into a dangerous form, and damaged DNA has the potential to cause mutations
and cancer. Free radical damage is associated
with almost very disease, including arthritis, heart disease, cataract, cancer,
Alzheimer's, and Parkinson's.
Antioxidants are molecules made by our bodies
to neutralize free radical damage. Antioxidants do this by donating an extra
electron to the free radical without becoming unstabilized itself, also preventing
the otherwise self-perpetuating free-radial process. Although the
antioxidant has donated an electron, thereby becoming a free radical, it has
the property of being much less reactive than the original radical it has quenched.
Being less active, the affected antioxidant does not cause further damage. When
Vitamin E functions as an antioxidant and donates its electrons, it cannot function
again until it has been "recharged", or had its missing electron replaced. This
is where Vitamin C enters the process. Vitamin C donates its electron to Vitamin
E, allowing Vitamin E to function again. Since certain types of antioxidants
work best in different environments - some are effective in the plasma environment
while others work their best within a fatty environment, there is no single
best antioxidant. They all work together. What develops is a complex network
or partnership of antioxidants that not only fight free radicals, but also serve
to regenerate one another. Hence, they work synergistically - that is, when
they are all present, their effect is greater than the sum of their individual
effects.
Fruits and vegetables are very high in antioxidants.
Unfortunately, diet by itself cannot provide the amount of antioxidants needed
for anti-aging purposes. For example, an orange, which is one of the
best sources of Vitamin C, contains about 65 mg of Vitamin C. To get 2,000 mg,
you would need to eat 30 oranges a day. Similarly, to get the 400 IU of Vitamin
E commonly recommended, you would have eat almost 5,000 calories of food, mostly
as fat. Supplementation, therefore, is a cornerstone for good health with respect
to antioxidants. Some common antioxidants available as supplements include:
Vitamin C, Vitamin E, carotenoids, glutathione, bioflavonoids, lipoic acid,
CoEnzyme Q 10, Selenium, and Grape Seed Extract.
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