Vitamin C
Definition
Vitamin C: An essential nutrient found mainly in fruits and vegetables.
The body requires vitamin C to form and maintain bones, blood vessels,
and skin.
Like other vitamins, vitamin C is an organic compound. An organic
compound is a substance that (1) occurs in living things, or organisms
(hence, the word "organic") and (2) contains the elements carbon and oxygen
(hence, the word "compound," meaning combination of elements). Vitamin C.
Definition
Vitamin C: An essential nutrient found mainly in fruits and vegetables.
The body requires vitamin C to form and maintain bones, blood vessels,
and skin.
Like other vitamins, vitamin C is an organic compound. An organic
compound is a substance that (1) occurs in living things, or organisms
(hence, the word "organic") and (2) contains the elements carbon and oxygen
(hence, the word "compound," meaning combination of elements). Vitamin C.
It has been suggested that daily intakes of vitamin C in excess of
500 milligrams may be of benefit. There is some evidence that amounts
of this kind may reduce the symptoms of the common cold. This raises
the question of non-nutritional or drug-like properties of the vitamin.
The possible adverse effects must also be considered. These include:'
rebound scurvy', which may occur if you are coming off high-dosage vitamin
C; increased excretion of oxalic acid in the urine which may lead to
'stones' in the urinary tract; an increased absorption of iron in those
susceptible to iron overload; increased absorption of toxic metals, such
as mercury; and interactions with certain medications, for example warfarin,
aspirin, antidepressants and the contraceptive pill. is also known as
ascorbic acid.
Approximately 5 to 10 mg of vitamin C is required daily to prevent scurvy.
The RDA is set higher to ensure an adequate body pool to prevent scurvy
after four weeks of low vitamin C intake. The 2000 recommendations are 15
to 45 mg for children, 65 to 90 mg for adolescents, 75 mg for adult females,
90 mg for adult males, 80-85 mg for pregnant women and 115-120 mg for
lactating women.
Vitamin C blocks carcinogenic processes through antioxidant activity.
Epidemiological studies have shown a strong association of vitamin C
supplementation with decreased risk of cancer of the oral cavity, esophagus,
stomach, and pancreas. Less strong associations were found with lung, cervix,
rectum, and breast cancer.
The daily intake for a gatherer hunter would depend on the season,
the particular ecosystem the tribe was living in, and the size of
the family unit that shared whatever resource was available. The daily
intake would probably have been well in excess of the RDA at times of year
when fruit and greens were relatively abundant, and at other times may well
have been much less. Either way, it is unlikely we took in 500 mg per day
every day. The 500 mg so called 'optimum' probably reflects the need for a
city living human to protect against stressful living, and the now wide
exposure to damaging environmental chemicals. Such a level can only
realistically be obtained by taking supplemental vitamin C.
Vitamin C is an important anti-oxidant, helps protect against cancers,
heart disease, stress, it is part of the cellular chemistry that provides
energy, it is essential for sperm production, and for making the collagen
protein involved in the building and health of cartilage, joints, skin, and
blood vessels. Vitamin C helps in maintaining a healthy immune system, it
aids in neutralizing pollutants, is needed for antibody production, acts
to increase the absorption of nutrients (including iron) in the gut, and
thins the blood. Just to mention its most important functions.
s a powerful antioxidant, vitamin C helps lessen oxidative stress
to the body and is thought to lower cancer risk. The current RDA
for vitamin C is 60mg, below is a list of foods high in vitamin C.
For those looking to consume extremely high levels of vitamin C
supplements are also available.
Oranges
Oranges, citrus fruits, and their zest (the shavings of their peel)
are all high in vitamin C. Oranges provide 59mg (99% RDA) per 100
gram serving, 98mg (163% RDA) per cup, and 83mg (138% RDA) per orange.
Clementines, or tangerines, provide 49mg (81% RDA) per 100 gram serving,
or 36mg (60% RDA) per fruit.
Consuming vitamin C supplements does not provide the same protective
benefits as drinking a glass of orange juice, shows research by Italian
researchers in the Division of Human Nutrition at the University of Milan,
Italy (Guarnieri S, Riso P, et al., British Journal of Nutrition).
Seven healthy test subjects were given each of three drinks, two weeks
apart: blood-orange juice containing 150 milligrams of vitamin C,
fortified water containing 150 milligrams of vitamin C, and a sugar
and water solution containing no vitamin C. Blood samples were collected
immediately before the drink was consumed, then every hour for 8 hours,
and finally 24 hours after consumption of each drink.
Blood samples were exposed to hydrogen peroxide, and free radical
damage to DNA was evaluated at 3 and 24 hours. Only when orange juice
was consumed was any protective effect seen. After drinking orange juice,
DNA damage was 18% less after 3 hours, and 16% less after 24 hours. No
protection against DNA damage was seen after consumption of the vitamin
C fortified drink or the sugar drink.
While another study, which looked at much larger quantities of vitamin C,
did show a protective effect from the vitamin alone, this research indicates
that not only is the protection afforded by fruit more complex, but smaller
amounts of nutrients like vitamin C are all that are needed for benefit.
Said lead researcher, Serena Guarnieri, "It appears that vitamin C is
not the only chemical responsible for antioxidant protection." In oranges,
vitamin C is part of a matrix involving many beneficial phytochemicals
(for example, cyanidin-3-glucoside, flavanones and carotenoids)..
"But how they are interacting is still anyone's guess," she added.
Fortunately, we don't have to wait until scientists figure this out
to receive oranges' DNA-protective benefits. Practical Tip: For the
best DNA protection, skip the vitamin C-fortified bottled drinks and
enjoy a glass of real (preferably organic as organic foods have been
shown to contain higher amounts of phytonutrients), freshly squeezed
orange juiceâ€"or simply eat an orange!
Owing to the multitude of vitamin C's health benefits, it is not
surprising that research has shown that consumption of vegetables
and fruits high in this nutrient is associated with a reduced risk
of death from all causes including heart disease, stroke and cancer.
Oranges' health benefits continue with their fiber; a single orange
provides 12.5% of the daily value for fiber, which has been shown to
reduce high cholesterol levels thus helping to prevent atherosclerosis.
Fiber can also help out by keeping blood sugar levels under control,
which may help explain why oranges can be a very healthy snack for
people with diabetes. In addition, the natural fruit sugar in oranges,
fructose, can help to keep blood sugar levels from rising too high
after eating. The fiber in oranges can grab cancer-causing chemicals
and keep them away from cells of the colon, providing yet another line
of protection from colon cancer. And the fiber in oranges may be
helpful for reducing the uncomfortable constipation or diarrhea in
those suffering from irritable bowel syndrome.
The obvious choice when it comes to the best foods with vitamin C
is oranges, which provide about 116% of your recommended daily
intake of the vitamin. Eating the orange slices as is is the best
source of the vitamin, but you can turn the oranges into juice
or buy 100% orange juice as well. The more you cook the fruit–in
other words, if you make marmalade or other orange desserts–the
less vitamins are retained.
