Scurvy sounds like something from a history book about sailors. Yet a severe vitamin C deficiency is still diagnosed occasionally, almost always in people who have barely eaten vegetables or fruit for months.
The core of it: on a varied diet, a deficiency is rare here. Vitamin C sits in so many products that avoiding it takes effort. A single kiwi or half a bell pepper already covers the daily need.
More interesting than the shortage, I think, is the top end. Above a certain dose your blood saturates, and swallowing more does almost nothing.
What does vitamin C do?
Vitamin C, also called ascorbic acid, is needed to build collagen, the protein that holds your skin, blood vessels, gums and bones together. It also helps you absorb plant-based iron and protects cells from damage. Unlike most animals, your body cannot make it.
That collagen role explains the classic symptoms of a shortage straight away. Without collagen, blood vessels and gums turn fragile.
What are the symptoms of a vitamin C deficiency?
Early complaints are general and unremarkable: tiredness, listlessness and muscle or joint pain. Only with a longer-standing shortage do the characteristic signs appear, such as bleeding gums, bruises that form too easily, and small wounds that refuse to close.
What often gets forgotten is that the first complaints are entirely unspecific. In the classic study where volunteers followed a vitamin C-poor diet, fatigue and muscle pain were the first things noticed, well before the gums began to bleed (Hodges 1971, PMID 5090631).
| Stage | What you might notice |
|---|---|
| Early | Fatigue, listlessness, muscle pain |
| Later | Bleeding gums, easy bruising |
| Advanced | Poor wound healing, skin changes around hair follicles |
| Risk groups | Very one-sided diet, alcohol dependence, heavy smokers |
Smokers use up more vitamin C, and the Dutch Voedingscentrum therefore sets a higher daily need for them than for non-smokers.
Where do you find vitamin C?
Mainly in vegetables and fruit, and not only in citrus. Bell pepper, sprouts, broccoli, kiwi and strawberries contain plenty, often more per portion than an orange. The Dutch Voedingscentrum sets a daily need of roughly 75 milligrams for adults, which a few portions of vegetables and fruit already cover.
What most people do not know: vitamin C is sensitive to heat and water. Prolonged boiling leaves a good part of it behind in the cooking water. Steaming or a quick stir-fry preserves more than a pan simmering for twenty minutes.
So eating things raw genuinely matters. A raw red bell pepper is one of the richest sources you will find in an ordinary supermarket.
Why does a higher dose not always help more?
Because your plasma saturates. Above a certain intake the concentration in your blood barely rises, however much you swallow. Your kidneys simply excrete the surplus. At roughly 200 milligrams a day, plasma concentration already sits close to its maximum (Levine 1996, PMID 8623000).
Picture two people who both assume more is better, one taking 200 milligrams a day and the other 2,000 milligrams. The difference in blood level is far smaller than that tenfold gap suggests. Most of that second tablet simply leaves the body in the urine.
The same applies to the best known claim about vitamin C. A Cochrane review of dozens of studies found that daily supplementation did not clearly reduce the chance of catching a cold in the general population, although duration seemed slightly shorter (Hemila 2013, PMID 23440782). That is a more nuanced story than the packaging suggests.
When is measuring vitamin C worthwhile?
Rarely, and I say that deliberately. Vitamin C in blood swings considerably with what you have eaten in recent days, so a single measurement mostly reflects your recent intake. On a varied diet without complaints, the test adds little.
There are exceptions. With a strongly one-sided diet, with alcohol problems, with serious eating difficulties, or with complaints that fit scurvy, a measurement can give direction. Then it is not about optimising but about ruling something out.
At Vitalcheck you can have vitamin C measured within an extended health checkup, without a referral. For the wider picture, read the pillar on minerals and trace elements, or read on about vitamin deficiency and which vitamins to test.
If you have complaints that fit a shortage, see your GP rather than supplementing on your own. A deficiency that genuinely exists deserves a diagnosis, not a guess.
References
- Hodges RE, et al. Clinical manifestations of ascorbic acid deficiency in man. Am J Clin Nutr. 1971. PMID 5090631.
- Levine M, et al. Vitamin C pharmacokinetics in healthy volunteers. Proc Natl Acad Sci U S A. 1996. PMID 8623000.
- Hemila H, Chalker E. Vitamin C for preventing and treating the common cold. Cochrane Database Syst Rev. 2013. PMID 23440782.
- Voedingscentrum. Vitamin C.
Every blood test result includes a professional assessment from a BIG-registered doctor. For treatment decisions, discuss your results with your GP.
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