Updated: Jan 28
Vitamin C is probably the most commonly known vitamin. Ask anyone to name a good source of vitamin B5 and you may be greeted with a blank stare, whereas if you were to ask them to name a good source of vitamin C they would almost certainly respond quickly with oranges and lemons. Many of us know where vitamin C is found and not many people are deficient in it even though it is an essential nutrient which we must obtain through food and drink as we cannot synthesise it endogenously. The question is, does vitamin C possess the ability to provide more benefits than we are aware of?
A Brief History
Vitamin C deficiency results in Scurvy. This disease was common amongst sailors in the Renaissance period, although it was recognised as far back as 1550BCE when it was described in the Ebers papyrus. It wasn't until 1747 that a link between Scurvy and vitamin C was discovered when British naval surgeon James Lind conducted a trial with 12 soldiers suffering from the disease. In the trial, he tested 6 different remedies for the disease and found lemons and oranges to be the most effective. By 1795, all British naval ships were issued with lime juice in order to combat scurvy which is why the Brits are known as "limeys" across the pond. Finally, in 1928, Hungarian biochemist Albert Szent-Györgyi isolated an organic reducing agent which he named "Hexuronic acid" which, thanks to work from British chemist Walter Haworth, is eventually renamed ascorbic acid aka vitamin C. For their work on the discovery and further research of vitamin C, Albert Szent-Györgyi and Walter Haworth receive the Nobel prize in Medicine and Chemistry respectively in 1937 (1) (2) (3).
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Sources of Vitamin C (source)
Kiwi - 93mg per 100g. One medium kiwi contains 79% RDV
Orange - 53mg per 100g. One medium orange contains 78% RDV
Lemon - 77mg per 100g. One whole lemon (peel included) contains 92% RDV. If you eat the peel of a lemon make sure it is an unwaxed lemon.
Strawberry - 59mg per 100g. 1 cup of strawberry halves contains 99% RDV.
Sweet yellow peppers - 183mg per 100g. 1 1/2 cup of sweet yellow peppers contains 152% RDV.
Lychees - 72mg per 100g. 1 cup of lychees contains 151% RDV.
Papaya - 62mg per 100g. 1 cup of papaya contains 97% RDV.
Guava - 228mg per 100g. 1 guava fruit contains 140% RDV.
Acerola Cherry - 1677.6mg per 100g. 1 1/2 cup of acerola cherries contains 913% RDV.
Kakadu Plum - Up to 5300mg per 100g. 1 single plum contains 530% RDV.
Kale - 120mg per 100g. 1 cup raw kale contains 89% RDV. 1 cup cooked kale contains 59% RDV. Eating raw kale is not recommended due to its high levels of oxalates. Steaming kale is better.
Broccoli - 89mg per 100g. 1 1/2 cup cooked broccoli contains 57% RDV
Parsley - 133mg per 100g. 2 tablespoons parsley contains 11% RDV
Thyme - 160mg per 100g. 2 tablespoons thyme contains 8% RDV
Red Cabbage Sauerkraut - Raw red cabbage contains up to 30mg of vitamin C per cup but when cabbage is fermented to make sauerkraut, the level of vitamin C increases drastically. One cup of red cabbage sauerkraut can contain up to 700mg of vitamin C whilst providing additional antioxidants and beneficial bacteria (4).
What it does
Vitamin C is most commonly thought of as an immune booster. Whilst this is true, the health benefits provided by vitamin C go beyond boosting the immune system.
Vitamin C is required for the biosynthesis of collagen, an important protein responsible for the production and maintenance of tendons, ligaments, blood vessels and skin. In fact, the skin contains high levels of vitamin C to assist in collagen formation and to protect against oxidative damage from sunlight (5). To find out more about collagen read our article here.
As previously mentioned, vitamin C is a powerful antioxidant. Antioxidants protect against free radical damage, also known as oxidative stress, which builds up inside the body over time. This can lead to diseases such as cancer, degenerative diseases and autoimmune disorders (6).
Improve iron absorption
Consuming vitamin C alongside foods rich in iron can increase the amount of iron you absorb (7). Iron is a component of haemoglobin in red blood cells which transports oxygen around the body. Iron is also a component of enzymes that are important for energy metabolism and a deficiency can lead to a condition called anaemia (8).
During times of illness or stress, concentrations of vitamin C in immune cells rapidly declines. Sufficient intake of vitamin C was shown to improve components of the immune system lymphocyte proliferation and immune cell function, and reduce the duration of respiratory tract infections (9).
Megadosing Vitamin C
Megadosing refers to the practice of taking oral or intravenous doses of vitamin C well above the recommended daily limit of 60-95mg, and often above the upper tolerable limit of 2,000mg per day. Whilst symptoms such as diarrhoea present at intakes of 2,000mg or over could be due to the fact that orally administered vitamin C would cause these problems as they interact with the gut this way. Healthy people do not generally need to consume more than 2,000mg of vitamin C per day, though some patients with pneumonia have taken up to 100g per day (50 times the upper tolerable limit) without any adverse effects, and another study showed healthy people given an intravenous dose of 100g within a few hours showed no side effects (10).
The potential therapeutic effects of high vitamin C doses was first put forward by Linus Carl Pauling in his 1970 book, Vitamin C and the Common Cold. Since then, therapy using high doses of vitamin C have been explored and could potentially provide alternative treatments in the future. As of the writing of this article, megadosing with vitamin C is not recommended by medical professionals.
If you would like to know more about the potential benefits of megadosing vitamin C check out these articles:
"Treating Illness with Megadose Vitamin C"
"Was Linus Pauling Right About Vitamin C’s Curative Powers After All?"
Vitamin C supplementation
Vitamin C supplements are mostly available in tablet form, either as chewable pills or effervescent tablets. The problem with these is the sweeteners they contain - usually aspartame. Aspartame, and other artificial sweeteners, though recognised as "safe for human consumption" by various health organisations, should be avoided if possible. Alternative supplements without sweeteners are available, as are supplements derived from fruits naturally high in vitamin C and other beneficial vitamins and polyphenols.
Vitamin C is an essential vitamin for humans as we cannot synthesise it ourselves. Deficiency in the vitamin is uncommon, though levels can be depleted during times of illness. Higher doses of vitamin C may be beneficial in times of illness, and very high doses of vitamin C could provide alternative benefits. Though studies have shown very high doses of vitamin C are tolerable to humans, it is always advisable to keep intake below the upper limit of 2,000mg when healthy.
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ABOUT THE AUTHORS
John Maitland is the co-founder of 'The Evolved Way.’ A personal trainer with over 10 years’ experience, he has worked alongside a wide range of leading CEOs, entrepreneurs and medical professionals. John is a keen athlete and holds a black belt in Shaolin Kung fu. A fan of the great outdoors, he can often be found exploring the British countryside and mountains...or breaking pine boards with his fingers.
Co-founder of 'The Evolved Way', and experienced personal trainer, Samson practices what he preaches. His own healthy lifestyle, which informs this site, is based on understanding the right way to eat and exercise, not excluding of course going out and enjoying life knowing you can still feel and look good.