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Myth or fact: does vitamin C have an effect on colds?

19.9.2024

Translation: Jessica Johnson-Ferguson

These days, it’s hard to be vitamin C deficient. For some people, however, an extra dose of vitamin c may be beneficial. Find how much of it your body needs and which food contains the most.

Searching for vitamin C supplements at Galaxus yields almost 150 results, and is only outdone by vitamin B preparations. So you’d be forgiven for thinking vitamin C is particularly tricky to absorb through normal food. What’s true is that your body can’t produce vitamin C, as it’s a water-soluble vitamin. This means you need to ingest sufficient amounts of it. You should aim for a daily average of 100 mg of ascorbic acid, as vitamin C is also referred to. Pregnant and breastfeeding people, as well as elderly people and competitive athletes, have a slightly higher requirement.

These foods contain lots of vitamin C

What’s your first association with vitamin C? Citrus fruit? Then you’ll be surprised to hear that other foods contain far more of this vitamin. However, you won’t find any in animal products. Many plant-based foods, on the other hand, will have you covered. 100 millilitres of a fruit smoothie, half a red bell pepper, two oranges or 100 grammes of Brussels sprouts are enough to cover your daily requirement. Keep in mind that vitamin C is very sensitive to light, heat and oxygen. This means you should go for fresh fruit and vegetables as well as gentle cooking methods (steaming, stewing, blanching) to ensure your vitamin C intake’s covered.

However, go easy on fruit juices. Although they’re packed with all kinds of vitamins (not just vitamin C), they also contain a relatively high amount of sugar. In other words, you’re better off getting your vitamin C from whole fruits, as they also provide extra fibre. If you still prefer to have fruit in liquid form, try opting for a smoothie instead of juice.

Incidentally, acerola cherries are the absolute leader in vitamin C content. At 1,700 milligrammes per 100 grammes, they contain many times more than other fruits. However, they’re not native to Europe and not suitable for import.

What your body needs vitamin C for

Vitamin C acts as an antioxidant in your body. This means it binds free radicals, thereby protecting your cells from damage. Its antioxidant effect is particularly important to protect you from oxidative stress, which is associated with various chronic diseases.

Many metabolic processes can only function properly with vitamin C. For example, it’s essential for the formation of connective tissue and bones. Vitamin C plays a crucial role in regulating the synthesis of collagen, a protein that’s essential to maintain the structure and function of skin, bones, blood vessels and other tissues.

But vitamin C is best known for boosting the immune system. Although vitamin C is important in this context, it’s by no means the miracle cure it’s often advertised as. Research has shown that taking extra vitamin C doesn’t protect the majority of people from catching a cold. There are exceptions, though. For people who put their bodies under extreme strain, such as marathon runners, extra vitamin C may reduce the risk of catching a cold. If you’ve already caught a cold, vitamin C may only shorten its duration slightly – by less than day on average. Better than nothing, but not groundbreaking, either.

However, vitamin C plays a decisive role in the absorption of iron. It helps your body absorb of non-haem iron (page in German) from plant sources. This form of iron’s less easily absorbed by the body than haem iron contained in animal foods. Vitamin C can therefore improve your iron supply, especially if you’re a vegetarian or vegan.

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Studies also suggest that vitamin C may have a positive influence on cardiovascular health. It can help lower blood pressure and improve endothelial function, which is important for the health of blood vessels.

What are the symptoms of vitamin C deficiency?

Vitamin C was discovered accidentally in the mid 18th century when mariner James Cook discovered that citrus fruit prevented the dreaded seafaring disease scurvy. It’s probably the most well-known disease caused by a lack of vitamin C. The condition is serious and triggered by extreme and long-lasting vitamin C deficiency. Its symptoms include bleeding gums, wound healing disorders and bleeding in the skin. Scurvy is very rare in developed countries, covering your vitamin C requirements is usually easy to achieve through a balanced diet.

A slight deficiency in vitamin C, on the other hand, is difficult to detect, as the deficiency shows itself in non-specific symptoms such as tiredness, headaches or an increased susceptibility to infections. People who smoke or have an unbalanced diet, alcoholics and older people are particularly at risk.

What else you should know about vitamin C

Vitamin C may play a role in treating cancer, but probably not in the way you expect. Studies (page in German) have shown that vitamin C in high doses can weaken the effect of some chemotherapy drugs, leading them to kill between 30 and 70 per cent fewer tumour cells.

By the way, did you know that our ancestors were capable of producing vitamin C themselves? Over the course of evolution, however, humans and some other primates lost this ability. To make up for this, these species have developed a way of recycling vitamin C more effectively. As a result, their daily requirement is significantly lower than that of animals that can produce vitamin C themselves. Goats, for example, need around 100 times as much as humans, as they produce it themselves and can only recycle it inefficiently.

Find out more about vitamins, minerals and fibre and why they’re essential for your health:

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More than an afterthought: why your body needs fibre, vitamins and minerals
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Header image: Filirovska/Pexels

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Anna Sandner

Senior Editor

Anna.Sandner@galaxus.de

Science editor and biologist. I love animals and am fascinated by plants, their abilities and everything you can do with them. That's why my favourite place is always the outdoors - somewhere in nature, preferably in my wild garden.

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