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Vitamin C

Ascorbic acid; Dehydroascorbic acid

Vitamin C is a water-soluble vitamin. It is needed for normal growth and development.

Water-soluble vitamins dissolve in water. Leftover amounts of the vitamin leave the body through the urine. Although the body keeps a small reserve of these vitamins, they have to be taken regularly to prevent a shortage in the body.

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Vitamin C benefit
Vitamin C deficit
Vitamin C source

Function

Vitamin C is needed for the growth and repair of tissues in all parts of your body. It is used to:

Vitamin C is one of many antioxidants. Antioxidants are nutrients that block some of the damage caused by free radicals.

The body is not able to make vitamin C on its own. It does not store vitamin C. It is therefore important to include plenty of vitamin C-containing foods in your daily diet.

For many years, vitamin C has been a popular household remedy for the common cold.

Food Sources

All fruits and vegetables contain some amount of vitamin C.

Fruits with the highest sources of vitamin C include:

Vegetables with the highest sources of vitamin C include:

Some cereals and other foods and beverages are fortified with vitamin C. Fortified means a vitamin or mineral has been added to the food. Check the product labels to see how much vitamin C is in the product.

The best food sources of vitamin C are uncooked or raw fruits and vegetables. Cooking vitamin C-rich foods or storing them for a long period of time can reduce the vitamin C content. Microwaving and steaming vitamin C-rich foods may reduce cooking losses. Exposure to light can also reduce vitamin C content. Choose orange juice that is sold in a carton instead of a clear bottle.

Side Effects

Serious side effects from too much vitamin C are very rare, because the body cannot store the vitamin. However, amounts greater than 2,000 mg/day are not recommended. Doses this high can lead to stomach upset and diarrhea. Large doses of vitamin C supplementation are not recommended during pregnancy. They can lead to shortage of vitamin C in the baby after delivery.

Too little vitamin C can lead to signs and symptoms of deficiency, including:

A severe form of vitamin C deficiency is known as scurvy. This mainly affects older, malnourished adults.

Recommendations

Recommendations for vitamin C, as well as other nutrients, are provided in the Dietary Reference Intakes (DRIs) developed by the Food and Nutrition Board at the Institute of Medicine. DRI is a term for a set of reference intakes that are used to plan and assess the nutrient intakes of healthy people. These values, which vary by age and sex, include:

Recommended Dietary Allowance (RDA): The average daily level of intake that is enough to meet the nutrient needs of nearly all (97% to 98%) healthy people. An RDA is an intake level based on scientific research evidence.

Adequate Intake (AI): This level is established when there is not enough scientific research evidence to develop an RDA. It is set at a level that is thought to ensure enough nutrition.

Dietary reference intakes for vitamin C:

Infants (AI)

Children (RDA)

Adolescents 

Adults

The best way to get the daily requirement of essential vitamins, including vitamin C, is to eat a balanced diet that contains a variety of foods.

Smokers or those who are around secondhand smoke at any age should increase their daily amount of vitamin C an additional 35 mg per day.

Women who are pregnant or breastfeeding and those who smoke need higher amounts of vitamin C. Ask your health care provider what amount is best for you.

Related Information

Scurvy

References

Litwack G. Vitamins and nutrition. In: Litwack G, ed. Human Biochemistry. Philadelphia, PA: Elsevier; 2018:chap 20.

Mason JB, Booth SL. Vitamins, trace minerals, and other micronutrients. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 205.

Markell M, Siddiqi HA. Vitamins and trace elements. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 27.

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Review Date: 3/11/2021  

Reviewed By: Meagan Bridges, RD, University of Virginia Health System, Charlottesville, VA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

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