Everything You Need to Know About Vitamin C

Vitamin C is a water-soluble vitamin, also known as ascorbic acid, that chiefly functions as an antioxidant. In the body, vitamin C works to protect cells from damage caused by free radicals, which are the compounds formed when our bodies convert food into energy. Because these  molecules have an unpaired electron, they are unstable and can interact with our cells (inside the body and on the skin) in a way that causes damage. There are also free radicals in the environment, such as air pollution, ultraviolet light, and tobacco smoke. Antioxidants, like vitamin C, neutralize the free radicals by donating the missing electrons and stabilize them, thus preventing damage. 

Other important roles of vitamin C include: synthesizing collagen (a structural protein in skin, bones, tendons, cartilage, and blood vessel walls), forming scar tissue, wound healing, and providing a matrix for bone growth. It is also required for the biosynthesis of L-carnitine and certain neurotransmitters, and it helps your body absorb nonheme iron (the iron found in plant-based foods). [1, 2]

What is the Recommended Daily Allowance (RDA) for vitamin C?

Intake recommendations are developed by the Food and Nutrition Board (FNB) at the Institute of Medicine (IOM) of the National Academies. Recommended Daily Allowance (RDA) is the average daily level of intake sufficient to meet the nutritional needs of nearly all (97-98%) healthy individuals. The current RDAs for vitamin C are based on its known physiological and antioxidant functions in white blood cells and are much higher than the amount required for protection from deficiency. [1] Because of vitamin C’s critical role within the body, First & Foremost provides the full RDA of vitamin C.

 

Recommended Dietary Allowance for vitamin C [1].

Age	Male	Female	Pregnant	Lactating
14-18 years	75 mg/ day	65 mg/ day	80 mg/ day	115 mg/ day
19+ years	90 mg/ day	75 mg/ day	85 mg/ day	120 mg/ day
Smokers	Individuals who smoke require 35 mg/ day more vitamin C than nonsmokers.

What is the best way to get vitamin C?

Supplemental vitamin C has equivalent bioavailability to that of naturally occurring ascorbic acid in foods, such as orange juice and broccoli. Approximately 70-90% of vitamin C is absorbed at moderate intakes of 30–180 mg/day, but at doses above 1 g/day, absorption falls to less than 50% and the unmetabolized ascorbic acid is excreted in the urine. [1]

Fruits and vegetables are great sources of vitamin C; including citrus fruits, tomatoes, and potatoes. Vitamin C is not naturally found in grains, but some breakfast cereals are fortified with vitamin C. Be aware that the content of vitamin C in food may be reduced by prolonged storage and by cooking because ascorbic acid is water-soluble and can be destroyed by heat. 

How does vitamin C react with other nutrients?

Vitamin C's role in enhancing iron's absorption is through the role of reducing ferric (nonheme) iron to the ferrous state. First & Foremost provides iron as Iron Bisglycinate Chelate, which is already in the ferrous state. Therefore, vitamin C is not needed to aid iron absorption, which is why they are provided in different occasions. 

It is commonly suggested, particularly for those with iron deficiency, to consume a vitamin C-rich food (providing at least 25 mg of vitamin C) such as orange juice when consuming nonheme iron-rich foods to promote the iron’s absorption as ferrous iron, which has higher solubility and better bioavailability than ferric iron [3]. 

Vitamin C Interactions with Medicine

Vitamin C supplements may interact with several types of medications. Consult your primary care provider if you are taking any of these medications or any other medications not listed.        

• Chemotherapy and radiation
• 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins)

What happens when you’re deficient in vitamin C?

Deficiency of vitamin C is known as scurvy, which usually presents when the total body vitamin C pool falls below about 300 mg and plasma body vitamin C concentrations drop to less than about 0.2 mg/dL. Scurvy can develop in as little as 1 month with vitamin C intake of less than 10 mg daily. However, the condition is more likely to occur with an inadequate intake for 4-6 months.  

Signs and symptoms of a deficiency include rough and bumpy skin, abnormally bent and corkscrew-shaped body hair, bright red hair follicles, spoon-shaped fingernails with red spots or lines, easy bruising, slow wound healing, painful and swollen joints, weak bones, bleeding gums and tooth loss, poor immunity, persistent iron deficiency anemia, and more. 

Groups at risk for vitamin C deficiency include: 

• Smokers and those who previously smoked. 
• Infants fed evaporated or boiled milk. 
• People who consume a limited variety of foods. 
• People with malabsorption and certain chronic diseases.

Can you take too much vitamin C?

Yes, you can overconsume vitamin C and it may cause minor GI discomfort. However, since vitamin C is a water-soluble vitamin, your body excretes any excess amounts within a few hours.

Oversupplementation with vitamin C long-term can cause adverse health effects. Even though your body does not store excess vitamin C and the excess can be eliminated through your urine, supplementing with high amounts can lead to adverse effects, such as digestive distress and kidney stones. The daily upper limits for vitamin C include intakes from all sources, including foods, drinks, and supplements, and are as follows.

Tolerable Upper Intake Levels (ULs) for Vitamin C [1]

Age	Male	Female	Pregnant	Lactating
14-18 years	1,800 mg/ day	1,800 mg/ day	1,800 mg/ day	1,800 mg/ day
19+ years	2,000 mg/ day	2,000 mg/ day	2,000 mg/ day	2,000 mg/ day

 

Since vitamin C increases iron absorption, consuming too much of it is a concern for individuals with conditions that lead to iron accumulation in the body. People with these conditions, like hemochromatosis, should be cautious with vitamin C supplements. That said, iron overload is highly unlikely if you don’t have a condition that increases iron absorption. Learn more about iron here. 

Furthermore, doses over 250 mg per day may interfere with tests designed to detect blood in the stool or stomach and should be discontinued two weeks prior to testing. [5]

How can I get the right amount of vitamin C?

Since the body does not store large amounts of vitamin C, it is recommended to eat fresh fruits and vegetables every day. 

• Consuming five varied servings of fruits and vegetables a day can provide more than 200 mg of vitamin C. 
• Vitamin C rapidly breaks down when exposed to heat, so raw fruits and vegetables are better sources than cooked ones.

References

1. https://ods.od.nih.gov/factsheets/VitaminC-HealthProfessional/
2. Advanced Nutrition and Human Metabolism; 7th edition; S. Gropper, J. Smith, T. Carr. Pages 303-312.
3. Murray-Kolbe LE, Beard J. Iron. In: Coates PM, Betz JM, Blackman MR, et al., eds. Encyclopedia of Dietary Supplements. 2nd ed. London and New York: Informa Healthcare; 2010:432-8.
4. Manoguerra, A. S., Erdman, A. R., Booze, L. L., Christianson, G., Wax, P. M., Scharman, E. J., Woolf, A. D., Chyka, P. A., Keyes, D. C., Olson, K. R., Caravati, E. M., & Troutman, W. G. (2005). Iron ingestion: an evidence-based consensus guideline for out-of-hospital management. Clinical toxicology (Philadelphia, Pa.), 43(6), 553–570. https://doi.org/10.1081/clt-200068842
5. Young GP, Symonds EL, Allison JE, et al. Advances in Fecal Occult Blood Tests: the FIT revolution. Dig Dis Sci. 2015;60(3):609-622. doi:10.1007/s10620-014-3445-3