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Vitamin
C: What Are the Benefits? And How Much is Too Much?
by
Don V. Richards
Vitamin
C, also known as ascorbic acid, is a nutrient that has a multiplicity
of health benefits. First of all, it is absolutely necessary for the
proper functioning of the human body - actually, for life itself:
Without sufficient Vitamin C, you'd die. Vitamin C is also
necessary for collagen production and therefore for healthy skin.
Vitamin C is known to boost the human immune system. This necessary
nutrient can also help our bodies fight off the common cold -
according to the most recent studies it can't reduce its incidence
or severity, but it can cut its duration.
Vitamin
C deficiency results in the disease scurvy, which can make you look
pale, with spots on your skin and bleeding mucous membranes, while it
makes you feel depressed and immobilized. Before scientists
understood this nutrient, sailors and others who ate only preserved
meats and grains - which don't contain Vitamin C - aboard ship
would often suffer from scurvy. Scurvy symptoms can show up among us
modern folks too, if we make very poor dietary choices. Scurvy, if
left untreated, is always fatal. But death from scurvy is rare,
because all that you need to do to be cured is to resume consuming a
healthy amount of Vitamin C.
Vitamin
C is also one of the most powerful antioxidants available. Cell
oxidization, which results in the breakdown of cell structures within
your body, is a result of the interaction of your cells with oxygen
and highly reactive substances called free radicals - and this
breakdown is a major cause of the signs of aging. Some oxidation is
necessary as a part of the process of life. But, unchecked,
oxidization can set off a chain reaction that can lead to
dysfunction, malformation, and death of cells on a massive scale.
Vitamin C, being an antioxidant, helps stop this chain reaction in
its tracks. In fact, Vitamin C is such a powerful antioxidant, it is
sometimes used a food additive specifically to prevent oxidization.
Vitamin
C is one of the few substances that has been found to be helpful
(though only modestly so) in fighting the common cold. Vitamin C has
also been found to have a mood-elevating effect. In a study of
hospital patients, who often have chronically low Vitamin C levels,
were found to have noticeably improved moods after taking Vitamin C
supplements. Considering that one of the early symptoms of Vitamin C
deficiency (ultimately leading to scurvy) is depression, that's not
surprising.
If
you're smoker, you really ought to stop that health-destroying
habit. But, until you do, it's important to know that smokers with
higher amounts of Vitamin C in their blood are somewhat less prone to
contract lung disease from smoking.
Many
animals can synthesize their own Vitamin C from within their bodies,
but humans and other higher primates, along with a few other animals
like bats and guinea pigs, cannot do so. So we and they must obtain
this essential nutrient in our diets, either by eating foods rich in
Vitamin C or by taking supplements. The process of pasteurization -
often used in milk and infant formula - destroys the chemical
structure of Vitamin C, by the way, so infants can actually sometimes
suffer from scurvy and in some cases supplementation is required.
Breast milk contains sufficient Vitamin C, though. Baby formulas
often are enriched with Vitamin C after the pasteurization process,
but heat and long storage can also destroy the nutrient, so pay
attention to expiration dates and storage practices.
The
human body can store only a limited amount of Vitamin C, and any
excess consumed is flushed out of the body - so for maximum health
benefit, our intake of this nutrient must be on a regular basis.
There is some controversy over what constitutes a healthy dose of
Vitamin C, and we'll be discussing that controversy in detail, so
read on.
Life
extension and natural health advocates emphasize that when we get
enough of this essential vitamin, we detoxify our bodies, prevent
disease, and strengthen the immune system (which helps us better deal
with stress). In all this they are in agreement with the medical
establishment. Where they differ is in their opinion of just how much
Vitamin C we should consume daily. Life extensionists say that the
Recommended Daily Allowance (RDA) of 90 mg of Vitamin C is too low.
That, they say, is enough to prevent scurvy but not enough to reap
other significant benefits. These health advocates point out that
other animals - guinea pigs and the higher primates like apes and
chimpanzees - which, like humans, do not synthesize their own
Vitamin C, generally consume 20
to 80 times
the RDA amount of Vitamin C every day when adjusted for body weight.
The great apes, similar to us in so many ways, usually consume 2,000
to 6,000 mg per day under normal circumstances.
One
health advocacy group, the Vitamin C Foundation, states that while
the amount of Vitamin C we need will vary based on our age, stress
level, diet, exposure to environmental toxins, and overall health,
their general recommendation is 1,000 to 4,000 mg per day for a
healthy person. They say a person with any significant disease will
need much more. Compare that to the Mayo Clinic's recommendation of
just barely meeting the Recommended Daily Allowance of 90 mg daily as
a minimum, and never exceeding 2,000 mg per day. (Assuming that
you're healthy, neither the Vitamin C Foundation nor the Mayo
Clinic would object to 1,000 to 2,000 mg per day, though - and
that's what I take, in case any of my readers are curious.)
Here's
a summary of some of the benefits of Vitamin C in recent scientific
studies according to the Vitamin C Foundation:
Sedentary
overweight men and women who started to take a 500 mg dose of Vitamin
C supplement daily experienced an average of a 13-pound weight loss.
Young
adults who began supplementation of Vitamin C at 250 mg and then
gradually increased their intake in steps until plateauing at 2,000
mg daily experienced a 60 to 90 per cent reduction in oxidative
stress, measured in just ten weeks.
Fully
82 per cent of Americans consume low or just marginally adequate
amounts of Vitamin C in their diets - enough to prevent scurvy
perhaps, but little more.
An
intake of 2000 mg per day of Vitamin C increases the effectiveness of
a certain kind of white blood cells - known as neutrophils - to
locate and kill (in a process called chemotaxis) disease-carrying
germs and even free-floating cancer cells.
One
study claims that oral Vitamin C when taken in divided high doses
can cause blood concentrations (over 73.8 micromole per liter) which
have been shown to reduce the risk of mortality from cancer by 57 per
cent and for all causes of death taken together by 62 per cent.
Nobel
Prize-winning scientist Linus Pauling was a strong advocate for high
daily doses of Vitamin C as a health-boosting regimen, something
which he practiced himself - and Pauling lived to the age of 93.
Pauling's claims are controversial and have often been dismissed or
minimized by the medical establishment. But some of Linus Pauling's
critics have changed their positions recently.
Pauling
stated that very high doses of the vitamin overcame the fragile half
life decay problem of the nutrient. He also advocated Vitamin C in
very high doses as a treatment for cancer, and some scientists who
initially dismissed his claims are now saying that the idea deserves
further investigation. Pauling (along with Canadian scientist G.C.
Willis) also stated that Vitamin C was beneficial for those suffering
from arthritis, since chronic low levels of the nutrient were a
probable cause of the disease.
Linus
Pauling's advocacy of Vitamin C megadoses - particularly his
promotion of high intravenous doses of C for cancer - proved to be
highly controversial. Pauling himself took 3,000 mg of Vitamin C
every day. Pauling - one of very few double Nobel Prize winners -
almost single handedly popularized Vitamin C in the 1960s and 1970s.
Pauling published studies showing a dramatic increase in survival for
cancer patients receiving very high intravenous doses of the vitamin.
Critics of Pauling, including the Mayo Clinic, asserted that his
studies were flawed and stated that the body excreted excess C
anyway, rendering Pauling's claims impossible. They published their
own studies claiming that Vitamin C didn't significantly benefit
cancer patients - they even called him a quack. Pauling called
these studies examples of "fraud and deliberate
misrepresentation, pointing out that oral, not intravenous Vitamin
C was used, and that some of the control group also received the
vitamin, along with other discrepancies. The battle was very
acrimonious, and, for a time, the study of Vitamin C in relation to
cancer was largely dropped. But some scientists - notably those
quoted in a 2009 review of the controversy in the journal Anticancer
Research
- now say that Linus's critics spoke too soon and further
investigation is called for.
So
how much is too much Vitamin C? Since it is water-soluble, excess
Vitamin C beyond that which the body can absorb is not stored and is
simply flushed out in the urine - so C has remarkably low toxicity.
A study in 1936 showed that a small but significant number of
subjects started to show adverse symptoms when they were given 6,000
mg per day of the nutrient: Among adults and children, these symptoms
included disturbed sleep, nausea, vomiting, diarrhea, flushing of the
face, headache, and fatigue. Among infants, the main symptom observed
was skin rashes. As I mentioned before, the Mayo Clinic recommends an
upper limit of 2,000 mg per day of Vitamin C supplements.
Vitamin
C is best taken as a component of the foods we eat as part of a
healthy, natural diet. Some foods that are high in Vitamin C include
citrus fruits, parsley, kiwifruit, chili peppers, red peppers, and
broccoli - in fact, most common produce contains some level of
Vitamin C. Some less common but potent sources include acerola
cherries, camu camu fruit, and rose hips. But be aware that Vitamin C
is relatively fragile, and cooking and even cutting and storage can
destroy some or all of this vital nutrient. Fresh is best!
As
a result of C's fragility in food, many of us rely on supplements
to get the amount of Vitamin C we need. Natural Vitamin C complexes,
derived directly from food sources, are said to be far more potent
than the cheaper, synthesized form of the vitamin. However, they are
also more expensive - and immunology expert Melissa Makris says
that mineral-derived Vitamin C is also effective, while being less
costly. She recommends avoiding Vitamin C synthesized from corn,
however, because the corn used these days is almost invariably a GMO
(genetically modified) variety.
REFERENCES
Mayo
Clinic Online, Nutrition and Healthy Eating, Is vitamin C good for
more than fighting colds?,
http://www.mayoclinic.org/healthy-living/nutrition-and-healthy-eating/expert-answers/benefits-vitamin-c/faq-20058271
, accessed April 29, 2014
Makris,
Melissa, Natural
News,
Health and Scientific Discoveries, The health benefits of vitamin
C go well beyond a stronger immune system,
http://www.naturalnews.com/032027_vitamin_C_immune_system.html ,
accessed April 29, 2014
Journal
of Nutrition,
volume 137, page 1757, 2007
Journal
of the American College of Nutrition,
volume 20: page 623, 2001
European
Journal of Clinical Nutrition,
volume 54: page 573, 2000
Journal
of the American College of Nutrition,
volume 11, page 172, 1992
American
Journal of Clinical Nutrition,
volume 72: page 139, 2000
Rivers,
J.M. (1987), "Safety of high-level vitamin C ingestion,"
Annals
of the New York Academy of Sciences
498: 445-54
Michels,
A. and Frei, B (2012). "Vitamin C," In Caudill M.A., Rogers
M., Biochemical,
Physiological, and Molecular Aspects of Human Nutrition
(3 ed.), Philadelphia: Saunders, pp. 627-654
Packer,
L. (1997), "Vitamin C and redox cycling antioxidants," In
Fuchs J., Packer L., Vitamin
C in health and disease,
New York: M. Dekker
"Linus
Pauling Vindicated; Researchers Claim RDA For vitamin C is Flawed"
(Press release), Knowledge of Health, July 6, 2004;
http://www.prnewswire.com/news-releases/linus-pauling-vindicated-researchers-claim-rda-for-vitamin-c-is-flawed-71172707.html
, accessed March, 17 2014.
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