Ascorbic Acid (C)

What is vitamin C?

Vitamin C, also known as ascorbic acid, is a vitamin that is essential for immunity, iron absorption, and other important processes. Vitamin C is water soluble, meaning it dissolves in water and is excreted from the body when consumed in large amounts.¹ Humans cannot produce vitamin C, so we must get this vitamin through our diet.

Why we need it

Vitamin C is an antioxidant, which means it protects against oxidative stress. Oxidative stress involves an imbalance between oxidants (highly reactive substances like hydrogen peroxide and hydroxyl radicals, which can damage healthy cells) and antioxidant defenses.² Vitamin C acts as an antioxidant by donating electrons to free radicals (a type of oxidant), making them less reactive.¹ Through its antioxidant activity, vitamin C helps the body heal wounds, fight infections, lower inflammation, and protect against chronic disease.³

Vitamin C is required to produce collagen, a structural protein found in the skin, bones, tendons, and cartilage.⁴ Specifically, vitamin C acts as a cofactor (a substance needed for an enzymatic reaction to occur) for various enzymes that synthesize collagen.³ In this way, vitamin C is important for skin health.

Additionally, Vitamin C can help you absorb iron from plant-based foods. Iron is found in food in two forms: heme iron (found in animal-based foods like meat) and nonheme iron (found in plant-based foods like leafy greens and fortified cereals).⁵ Heme iron is absorbed much more easily, which is why iron may be a concern for people who do not eat meat.⁵ Fortunately, vitamin C converts nonheme iron into a form that is more easily absorbed in the intestine.¹ This means that pairing plant-based foods with vitamin C-rich foods can help you get more iron from your diet!

Where it’s found

Vitamin C is found in many foods, mainly fruits and vegetables. The following are some examples of foods that are high in vitamin C:

• Bell peppers
• Broccoli
• Cantaloupe
• Citrus fruits
• Fortified breakfast cereals
• Grapefruit
• Kiwi
• Potatoes
• Spinach
• Strawberries
• Tomatoes

Vitamin C is also available in supplement form. You can take it as a tablet, or as a powder that can be mixed with water.

Daily requirements

The Recommended Dietary Allowance for vitamin C (i.e. the amount that is likely to meet the needs of most healthy people) is 90 milligrams (mg) per day for adult males (over 19 years old), and 75 mg per day for adult females.⁶

Some people may require more vitamin C. Smokers, for example, are recommended to get an additional 35 mg per day.¹ This is partly because these individuals use more vitamin C to counteract the oxidative effects of smoking.¹

Vitamin C deficiency

Severe vitamin C deficiency can cause scurvy, a disease characterized by poor immune function and difficulty healing wounds.³ Symptoms of scurvy include bleeding gums, bruising, and fatigue.^{1, 3} Scurvy is a serious illness that may be fatal if left untreated.¹

Vitamin C deficiency is rare in developed countries, but certain groups of people may be at higher risk. For instance, vitamin C deficiency is more likely among people with poor dietary habits, smokers, pregnant women, people of low socioeconomic status, and infants or elders.¹

Luckily, vitamin C deficiency can be prevented relatively easily. Vitamin C intake can be as low as 10 mg per day before signs of deficiency arise.³

Can you get too much vitamin C?

Our bodies can readily excrete vitamin C, so toxicity is unlikely. The Tolerable Upper Limit for vitamin C (i.e. the maximum amount that is likely to be safe for most people) is 2,000 mg for adults (male and female).⁶ Consuming vitamin C beyond this level may cause digestive distress, but there is little evidence to suggest more serious harm.¹

Fun facts

One of the world’s richest sources of vitamin C is the camu berry, which is a fruit that originates from Peru and Brazil. 100 grams of camu berry pulp provides up to 3000 mg of vitamin C,⁷ which is over 30 times the RDA!

Vitamin C can be broken down by heat, so some may be lost through cooking. Incorporating fresh fruits and vegetables into your diet can help ensure you are getting enough vitamin C!

References

1. Lykkesfeldt, J., Michels, A. J., & Frei, B. (2014). Vitamin C. Advances in nutrition (Bethesda, Md.), 5(1), 16–18.
2. Forman, H. J., & Zhang, H. (2021). Targeting oxidative stress in disease: promise and limitations of antioxidant therapy. Nature reviews. Drug discovery, 20(9), 689–709.
3. Carr, A. C., & Maggini, S. (2017). Vitamin C and Immune Function. Nutrients, 9(11), 1211.
4. Gelse, K., Pöschl, E., & Aigner, T. (2003). Collagens--structure, function, and biosynthesis. Advanced drug delivery reviews, 55(12), 1531–1546.
5. Geissler, C., & Singh, M. (2011). Iron, meat and health. Nutrients, 3(3), 283–316.
6. Institute of Medicine. (2011). Dietary Reference Intakes for Calcium and Vitamin D. Washington, DC: The National Academies Press.
7. Justi, K. C., Visentainer, J. V., Evelázio de Souza, N., & Matsushita, M. (2000). Nutritional composition and vitamin C stability in stored camu-camu (Myrciaria dubia) pulp. Archivos latinoamericanos de nutrición, 50(4), 405–408.

Dietary supplement

You can use a dietary supplement of Ascorbic Acid (C) if you think your diet lacks this nutrient.

Supports the immune system and helps neutralize free radicals in the body.

Use the list below to check if your diet has enough Ascorbic Acid (C) intake.

Food high in Ascorbic Acid (C)

This list shows food that are top sources of Ascorbic Acid (C) and the quantity of Ascorbic Acid (C) in 100g of food