What is vitamin C and what does it do?
Vitamin C, also known as 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 environ-
ment from cigarette smoke, air pollution, and ultraviolet light from the sun.
e 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?
e amount of vitamin C you need each day depends on your age. Average daily
recommended amounts for dierent ages are listed below in milligrams (mg).
Life Stage Recommended Amount
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 recom-
mended amount.
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 fortied with vitamin C. To nd out if vitamin C
has been added to a food product, check the product labels.
e 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.
You can get enough vitamin C
by eating a variety of foods
including citrus fruits (such as
oranges and grapefruit) and
their juices, as well as red and
green pepper, kiwifruit, broccoli,
strawberries, baked potatoes,
and tomatoes.
Vitamin C Fact Sheet for Consumers
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. e 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 bioavonoids. 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 vita-
min C?
Vitamin C deciency 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,
inammation 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 aects
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 eects 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. But 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 oncolo-
gist 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 respon-
sible 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 (AMD)
and cataracts
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 aect the risk of getting AMD. However,
research suggests that vitamin C combined with other nutri-
ents might help slow AMD progression.
In a large study among, older people with AMD who were at
high risk for developing advanced AMD, those who took a
daily dietary supplement with 500 mg vitamin C, 80 mg zinc,
400 IU vitamin E, 15 mg beta-carotene, and 2 mg copper
for about 6 years had a lower chance of developing advanced
AMD. ey also had less vision loss than those who did not
take the dietary supplement. People who have or are develop-
ing the disease might want to talk with their doctor about
taking dietary supplements.
e 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. But further
research is needed to clarify this association and to determine
whether vitamin C supplements aect the risk of getting
cataracts.
2 • VITAMIN C FACT SHEET FOR CONSUMERS
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 hemochro-
matosis, which causes the body to store too much iron, high
doses of vitamin C could worsen iron overload and damage
body tissues.
e daily upper limits for vitamin C are listed below:
Life Stage Upper Limit
Birth to 12 months Not established
Children 1–3 years 400 mg
Children 4–8 years 650 mg
Children 9–18 years 1,200 mg
Teens 14–18 years 1,800 mg
Adults 2,000 mg
Are there any interactions with vitamin C
that I should know about?
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 eect
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 eects 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. ey
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, advises
the federal government’s Dietary Guidelines for Americans.
Foods contain vitamins, minerals, dietary ber and other
substances that benet health. In some cases, fortied foods
and dietary supplements may provide nutrients that otherwise
may be consumed in less-than-recommended amounts. For
more information about building a healthy diet, refer to the
Dietary Guidelines for Americans and the U.S. Department of
Agriculture’s MyPlate.
Where can I find out more about vitamin C?
For general information on vitamin C:
• Oce of Dietary Supplements Health Professional Fact
Sheet on Vitamin C
• Vitamin C, MedlinePlus
®
For more information on food sources of vitamin C:
• U.S. Department of Agriculture’s (USDA’s) National
Nutrient Database
• Nutrient list for vitamin C (listed by food or by vitamin C
content), USDA
For more advice on buying dietary supplements:
• Oce of Dietary Supplements Frequently Asked Questions:
Which brand(s) of dietary supplements should I purchase?
For information about building a healthy diet:
• MyPlate
• Dietary Guidelines for Americans
Disclaimer
is fact sheet by the Oce of Dietary Supplements provides
information that should not take the place of medical advice.
We encourage you to talk to your health care providers (doctor,
registered dietitian, pharmacist, etc.) about your interest in,
questions about, or use of dietary supplements and what may
be best for your overall health. Any mention in this publication
of a specic brand name is not an endorsement of the product.
3 • VITAMIN C FACT SHEET FOR CONSUMERS
For more information on this and other supplements, please visit our
Web site at: http://ods.od.nih.gov or e-mail us at [email protected]
Updated: December 10, 2019
