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Vitamin C

(Ascorbic acid)
What is Vitamin C and what does it do?
Vitamin C, also known as
L-ascorbic acid, is a
water-soluble nutrient found
in some foods. In the body, it acts as an antioxidant,
helping to protect cells from
the damage caused by free
radicals. Free radicals are compounds formed
when our bodies convert the food we eat into energy. People
are also exposed to free radicals in the environment from
cigarette smoke, air pollution, and ultraviolet
light from the sun.
The body also needs Vitamin C to make collagen,
a protein required
to help wounds heal. In addition, Vitamin C improves the absorption of iron from
plant-based foods and helps the immune
system work properly to protect the body from disease.
How much Vitamin C do I need?
When it comes to Vitamin C, a little bit goes a long way —
which is to say, it’s not all that difficult to get your
recommended daily amount. For example, one medium orange has
about 80 milligrams of Vitamin C, which accounts for much of
your daily intake.
The amount of Vitamin C you need each day depends on your
age.
verage daily recommended amounts for different ages
are listed below in milligrams (mg).
Life Stage |
RDA |
Birth to 6 months |
40 mg |
Infants 7–12 months |
50 mg |
Children 1–3 years |
15 mg |
Children 4–8 years |
25 mg |
Children 9–13 years |
45 mg |
Teens 14–18 years (boys) |
75 mg |
Teens 14–18 years (girls) |
65 mg |
Adults (men) |
90 mg |
Adults (women) |
75 mg |
Pregnant teens |
80 mg |
Pregnant women |
85 mg |
Breastfeeding teens |
115 mg |
Breastfeeding women |
120 mg |
If you smoke, add 35 mg to the above values to calculate
your total daily recommended amount. “Keep in mind that these recommendations are a minimum to
prevent deficiency,” Peart says, “and some experts believe
the recommendations should be higher.” These recommendations also don’t take into account bodily
differences like weight, height, sex, overall health, etc.
Plus, if you smoke, you’ll need about 35 mg more per day
because smoking is toxic to cells, causing your body to use
up its Vitamin C more quickly. If you’re not sure how much Vitamin C you should be getting,
talk to a healthcare provider for personalized guidance.
Health benefits of Vitamin C
What does Vitamin C actually do for your body? Peart delves deeper into
some of the proven ways that it supports your health, plus a few
possibilities that are still being researched.
1. Fights cell damage and disease
Vitamin C is an antioxidant, a natural chemical found in certain foods.
You can think of antioxidants like invisible superheroes inside your
body. Their main job is to protect you from free
radicals, or unstable molecules that can damage your cells, cause
oxidative stress, increase signs of aging and more.
“A buildup of free radicals is associated with a risk of diseases like
cancer, heart disease and arthritis,” Peart explains. Eating
antioxidant-rich foods, like those high in Vitamin C, can help protect
your body from free radical-related damage.
2. Protects your eyes
Vitamin “see” indeed: This antioxidant is thought to help ward off cataracts (a
clouding of the lens of your eye) and slow the progression of age-related
macular degeneration (AMD), a condition that causes people to lose
their central vision.
“Studies have shown mixed
results,” Peart notes, “but we know that Vitamin C acts as an
antioxidant for cells in the retina and macular region of the eye.”
3. Improves iron absorption
Some plant foods, including beans and spinach, have iron in them (a type
called non-heme
iron), but they also have properties that make it hard for your body
to access that iron. Enter Vitamin C, which acts as iron’s wingman.
“Consuming foods that are high in Vitamin C in the same meal with
iron-rich plant foods boosts the bioavailability of the iron, meaning
that you absorb more of it,” Peart explains.
Let’s say you make a spinach salad with strawberries on top. Spinach has
non-heme iron, while strawberries are rich in Vitamin C. They’re both
healthy on their own, but when you eat them together, the Vitamin C in
the strawberries helps your body access and absorb more iron from the
spinach than it could if you just ate the spinach alone.
4. Helps with wound healing
Vitamin C encourages collagen growth,
which is an important part of your body’s healing process. “Collagen is
a protein that keeps our skin looking young,” Peart adds.
It’s one of the keys to properly
healing wounds, including cuts, scrapes and surgical incisions. And
people who don’t get enough Vitamin C have been shown to heal
more slowly than those who get the recommended amount.
5. Promotes healthy skin
We’re mostly talking about the kind of Vitamin C that you find in foods,
but it’s worth noting that topical creams
and serums made with Vitamin C can do all kinds of good things for
your skin. They help slow signs of aging, reduce dark under-eye circles
and even bolster the effects of sunscreen. (Psst: You are wearing
sunscreen, aren’t you? Hint, hint.)
Other possible benefits
Science never stops! There are always studies in progress to uncover new
health information, including the many roles Vitamin C plays in our
bodies. Here are a few other possible benefits of Vitamin C, though more
research is needed on all of them:
-
May help you recover quickly: Contrary to what you might’ve
heard, Vitamin C can’t prevent you from getting sick (sorry). But
it can still
be of help. “Some studies suggest that it can help lessen
the severity and duration of colds and the flu and potentially
reduce your risk of further complications,” Peart says.
-
May improve heart health: Vitamin C may
help prevent and treat cardiovascular disease (CVD), including
strokes. Studies so far have been conflicting, though, so
researchers still can’t say for certain how effective it might be.
-
May play a role in cancer treatments: As researchers
continue to learn about cancer, genetics, Vitamin C absorption and
metabolism, Peart says they’re exploring the
role Vitamin C might play in treating some types of cancers.
“There is some
promising evidence so far, as an adjunct to conventional cancer
treatment,” she says. This means it could play a role in — but not
replace — treatment.
What foods provide Vitamin C?
Fruits and vegetables are the best sources of Vitamin C. You
can get recommended amounts of Vitamin C by eating a variety
of foods including the following:
- Citrus fruits (such as
oranges and grapefruit) and their juices as well as red
and green pepper and kiwifruit, which have a lot of
Vitamin C.
- Other fruits and
vegetables—such as broccoli, strawberries, cantaloupe,
baked potatoes, and tomatoes—which also have Vitamin C.
- Some foods and beverages
that are fortified with
Vitamin C. To find out if Vitamin C has been added to a
food product, check the product labels.
The Vitamin C content of food may be reduced by prolonged
storage and by cooking. Steaming or microwaving may lessen
cooking losses. Fortunately, many of the best food sources
of Vitamin C, such as fruits and vegetables, are usually
eaten raw.
What kinds of Vitamin C dietary supplements are available?
Most multiVitamins have
Vitamin C. Vitamin C is also available alone as a dietary
supplement or in combination with other nutrients. The
Vitamin C in dietary supplements is
usually in the form of ascorbic acid, but some supplements
have other forms, such as sodium ascorbate, calcium ascorbate,
other mineral ascorbates,
and ascorbic acid with bioflavonoids. Research has not shown
that any form of Vitamin C is better than the other forms.
Am I getting enough Vitamin C?
Most people in the United States get enough Vitamin C from
foods and beverages. However, certain groups of people are
more likely than others to have trouble getting enough
Vitamin C:
- People who smoke and
those who are exposed to secondhand
smoke, in part because smoke increases the amount of
Vitamin C that the body needs to repair damage caused by
free radicals. People who smoke need 35 mg more Vitamin
C per day than nonsmokers.
- Infants who are fed
evaporated or boiled cow’s milk because cow’s milk has
very little Vitamin C and heat can destroy Vitamin C.
Cow’s milk is not recommended for infants under 1 year
of age. Breast milk and infant
formula have adequate amounts of Vitamin C.
- People who eat a very
limited variety of food.
- People with certain
medical conditions such as severe malabsorption,
some types of cancer,
and kidney
disease requiring hemodialysis.
What happens if I don’t get enough Vitamin C?
Vitamin C deficiency is rare in the United States and
Canada. People who get little or no Vitamin C (below about
10 mg per day) for many weeks can get scurvy. Scurvy
causes fatigue, inflammation of the gums, small red or
purple spots on the skin, joint pain, poor wound healing,
and corkscrew hairs. Additional signs of scurvy
include depression as well as swollen, bleeding gums and
loosening or loss of teeth. People with scurvy can also
develop anemia. Scurvy is fatal if it is not treated.
What are some effects of Vitamin C on health?
Scientists are studying Vitamin C to understand how it
affects health. Here are several examples of what this
research has shown.
Cancer prevention and treatment
People with high intakes of Vitamin C from fruits and
vegetables might have a lower risk of getting many types of
cancer, such as lung, breast, and colon cancer. However,
taking Vitamin C supplements, with or without other
antioxidants, doesn’t seem to protect people from getting
cancer.
It is not clear whether taking high doses of Vitamin C is
helpful as a treatment for cancer. Vitamin C’s effects
appear to depend on how it is administered to the
patient. Oral doses of Vitamin C can’t raise blood levels of
Vitamin C nearly as high as intravenous doses given
through injections. A few studies in animals and test tubes
indicate that very high blood levels of Vitamin C might
shrink tumors. However, more research is needed to determine
whether high-dose intravenous Vitamin C helps treat cancer
in people.
Vitamin C dietary supplements and other antioxidants
might interact with chemotherapy and radiation therapy for
cancer. People being treated for cancer should talk with
their oncologist before taking Vitamin C or other
antioxidant supplements, especially in high doses. Cardiovascular disease
People who eat lots of fruits and vegetables seem to
have a lower risk of cardiovascular
disease. Researchers believe that the antioxidant
content of these foods might be partly responsible for
this association because oxidative
damage is a major cause of cardiovascular disease.
However, scientists aren’t sure whether Vitamin C
itself, either from food or supplements, helps protect
people from cardiovascular disease. It is also not clear
whether Vitamin C helps prevent cardiovascular
disease from getting worse in people who already have
it. Age-related macular degeneration and cataracts
Age-related macular degeneration (AMD)
and cataracts are
two of the leading causes of vision loss in older
people. Researchers do not believe that Vitamin C and
other antioxidants affect the risk of getting AMD.
However, research suggests that Vitamin C combined with
other nutrients might help slow AMD progression.
In a large study among older people with AMD who were at
high risk of developing advanced AMD, those who took a
daily dietary supplement with 500 mg Vitamin C, 80 mg zinc,
400 International Units (IU) Vitamin
E, 15 mg beta-carotene,
and 2 mg copper for
about 6 years had a lower chance of developing advanced
AMD. They also had less vision loss than those who did
not take the dietary supplement. People who have or are
developing the disease might want to talk with their
doctor about taking dietary supplements.
The relationship between Vitamin C and cataract
formation is unclear. Some studies show that people who
get more Vitamin C from foods have a lower risk of
getting cataracts. However, further research is needed
to clarify this association and to determine whether
Vitamin C supplements affect the risk of getting
cataracts. The common cold
Although Vitamin C has long been a popular remedy for
the common
cold, research shows that for most people, Vitamin C
supplements do not reduce the risk of getting the common
cold. However, people who take Vitamin C supplements
regularly might have slightly shorter colds or somewhat
milder symptoms when
they do have a cold. Using Vitamin C supplements after
cold symptoms start does not appear to be helpful.
Can Vitamin C be harmful?
Taking too much Vitamin C can cause diarrhea, nausea,
and stomach cramps. In people with a condition called hemochromatosis,
which causes the body to store too much iron, high doses of
Vitamin C could worsen iron overload and damage body tissues.
The daily upper
limits for Vitamin C include intakes from all
sources—food, beverages, and supplements—and are listed
below.
Life Stage |
Upper Limit
(per day) |
Birth to 12 months |
Not established |
Children 1–3 years |
400 mg |
Children 4–8 years |
650 mg |
Children 9–13 years |
1,200 mg |
Teens 14–18 years |
1,800 mg |
Adults |
2,000 mg |
Interaction with Medications or Supplements?
Vitamin C dietary supplements can interact or interfere with
medicines that you take. Here are several examples:
- Vitamin C dietary
supplements might interact with cancer treatments, such
as chemotherapy and radiation therapy. It is not clear
whether Vitamin C might have the unwanted effect of
protecting tumor cells from cancer treatments or whether
it might help protect normal tissues from getting
damaged. If you are being treated for cancer, check with
your health
care provider before taking Vitamin C or other
antioxidant supplements, especially in high doses.
- In one study, Vitamin C
plus other antioxidants (such as Vitamin E, selenium,
and beta-carotene) reduced the heart-protective effects
of two drugs taken
in combination (a statin and niacin)
to control blood-cholesterol levels.
It is not known whether this interaction also occurs
with other statins. Health care providers should monitor
lipid levels in people taking both statins and
antioxidant supplements.
Tell your doctor, pharmacist,
and other health care providers about any dietary
supplements and medicines you take. They can tell you if
those dietary supplements might interact or interfere with
your prescription or
over-the-counter medicines or if the medicines might
interfere with how your body absorbs, uses, or breaks down
nutrients.
Vitamin C and healthful eating
People should get most of their nutrients from food and
beverages, according to the federal government’s Dietary
Guidelines for Americans. Foods contain Vitamins,
minerals, dietary
fiber, and other components that benefit health. In some
cases, fortified foods and dietary supplements are useful when it is not
possible to meet needs for one or more nutrients (for example, during
specific life stages such as pregnancy).
One Final Note..
Vitamin C supplements have been marketed for many
conditions. Ultimately, it's the best treatment for Vitamin
C deficiency. As an antioxidant and anti-inflammatory, Vitamin C has been
studied for its uses in heart disease prevention, gout,
immunity, and more. It is best to get Vitamin C from your food. But if you
don't, a supplement can help you meet your goals. Talk to
your healthcare provider before taking supplements. The right dosage depends on several factors, including age
and medical conditions. In addition, Vitamin C can interact
with certain medications and cause side effects at high
levels, so it is important to discuss with your healthcare
provider whether supplementation is appropriate for you.
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