Vitamin C – What Is It?

Vitamin C structureVitamin C is also known as ascorbic acid in its reduced form and dehydroascorbic acid in its oxidized form.  Since this vitamin receives and donates electrons, it can act as an antioxidant.  All plants and most animals make ascorbic acid.  Humans cannot make vitamin C, so we must obtain it from our diet.

Vitamin C is absorbed in the small intestine and is found in high concentrations in tissues such as the pituitary gland, adrenal glands, white blood cells, eyes, and brain.  Depending on intake, 70-90% of this vitamin is absorbed into the body.  Like most water-soluble vitamins, any excess is excreted in urine.

What Does It Do?

When most people think of vitamin C, they think of its antioxidant properties.  However, the primary purpose of vitamin C is to perform as a reducing agent, donating electrons to enzymatic, as well as non-enzymatic, reactions.  In its oxidized state, it has the ability to reduce iron and copper.  Vitamin C is also involved in collagen synthesis; fatty acid metabolism; the absorption of dietary nonheme iron; the synthesis of the neurotransmitter serotonin, corticosteroids and aldosterone; cholesterol conversion into bile acids; and amino acid (tyrosine) metabolism.  Further, vitamin C is involved in immune function because of its antioxidant roles and can act as a natural antihistamine.

Where Can You Find It?

Vitamin C FoodsAll fruits and vegetables contain at least a little vitamin C.  While some animal products and grains contain this vitamin, they are not considered good dietary sources.  Generally speaking, citrus fruits, potatoes, and green vegetables are good sources of vitamin C.  Specifically, oranges, brussel sprouts, strawberries, grapefruit juice, red and green peppers, kiwis, tomato juice, broccoli, and kale are rich sources of vitamin C.

Vitamin C can be lost during the processing and cooking processes, as it becomes unstable when it contacts heat, iron, copper, and oxygen.  Therefore, the best way to consume vitamin C is from raw or minimally processed and cooked fruits and vegetables.

How Much Do You Need?

The RDAs for vitamin C is shown below: 



Upper   Limit

Infants and children
0-6 months

40   mg

7-12 months

50   mg

1-3 years

15   mg

400   mg

4-8 years

25   mg

650   mg

9-13 years

45   mcg

1,200   mg

Adolescents, 14-18 years

75   mg

1,800   mg


65   mg

1,800   mg

Adults, 19+

90   mg

2,000   mg


75   mg

2,000   mg


85   mg

2,000   mg


120   mg

2,000   mg

The RDA for children 12 months or less appears higher than slightly older children because the Adequate Intake of this vitamin was established from the quantity found in breast milk.  Therefore, no Upper Limit could be calculated for these age groups.

Further, it is recommended that smokers should intake 35 mg more per day than non-smokers.

What Happens If You Don’t Get Enough?

Pinpoint hemorrhages associated with scurvy

Pinpoint hemorrhages associated with scurvy

Scurvy is the most commonly known disease to occur with an acute deficiency of vitamin C.  Since this vitamin is involved in collagen synthesis, a deficiency in this vitamin can lead to significant changes in connective tissue throughout the body.  The first signs of scurvy include fatigue and pinpoint hemorrhages around hair follicles on the backs of arms and legs.  Other signs include slow wound healing, bone pain, fractures, swollen gums, loose teeth, and diarrhea.  Psychological issues, such as depression and dementia, can occur in the advanced stages of scurvy, followed by death.

Scurvy is mostly associated with people who do not eat many fruits and vegetables.  Vitamin C deficiency can also occur in alcoholics and drug-abusers, as their diets are usually nutrient-poor.

I wrote an interesting history of scurvy in an earlier post titled “Some Nutrition Truths,” if you’d like to read more.

What Happens If You Take Too Much?

Consuming high amounts of vitamin C on a regular basis, especially through vitamin supplements, can lead to stomach inflammation and diarrhea.  Therefore, there is an Upper Limit to this vitamin for practically every age group.

Since vitamin C can act as an antioxidant, people seem to think that more is better.  However, when too much of this vitamin is consumed, it can have oxidant properties (meaning that it actually CAUSES damage).  Therefore, taking massive doses of the vitamin to try to fight off a cold, or to prevent cardiovascular disease or certain types of cancer is NOT recommended unless prescribed by a doctor.  Like most things in life, a little is good for you, while too much may not be.

Bottom Line

The best way to consume any nutrient in order to avoid over- or under-consumption is to consume a wide variety of foods, in a wide variety of colors, and eat according to MyPlate.

Until next time, remember that… there are no excuses when it comes to your health!


3 thoughts on “Vitamin C – What Is It?

  1. Pingback: Antioxidants to Boost Your Health « Fun with Food Fun with Food

  2. Pingback: The 7 most alkaline foods | Start to be Healthy Now

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