Vitamin C: Effects, Daily Requirement & the Best Source

A single red bell pepper covers your entire daily requirement of vitamin C – and does so twice over. Even so, hardly any vitamin is as popular a dietary supplement as vitamin C. Why exactly? Because this molecule (ascorbic acid) is involved in astonishingly many jobs in the body – from the immune system to the skin to iron absorption – and because we humans, unlike most animals, cannot produce it ourselves. This guide clears up half-truths: what vitamin C really does, how much you need per day and whether the expensive acerola capsule is superior to cheap ascorbic acid.

The key points at a glance

• Vitamin C contributes to the normal function of the immune system and helps protect the cells from oxidative stress.
• It is indispensable for collagen formation – and therefore for skin, bones, cartilage, teeth and blood vessels.
• Vitamin C increases iron absorption from plant-based food – a strong duo, especially in cases of iron deficiency.
• According to the DGE, the daily requirement is around 95–110 mg; smokers and athletes have an increased requirement.
• Chemically, ascorbic acid from acerola and from synthetic production is identical – natural sources merely provide additional secondary plant compounds.

What vitamin C really does in the body

Vitamin C is far more than the "cold vitamin" that many people know it as. On a cellular level it is a central electron donor – it can release electrons and thus act as an antioxidant, capturing reactive oxygen species before they attack cell structures. At the same time it is a co-factor for a number of enzymes: without vitamin C, for example, the enzymes that stabilise collagen do not run smoothly. That is why vitamin C is one of the few nutrients where a genuine deficiency has visible consequences for skin, gums and connective tissue.

For many of these functions, official, scientifically reviewed statements (health claims) are approved in the EU. The most important ones at a glance:

Important to understand: these claims apply to an adequate supply – more vitamin C does not automatically bring more effect. The body keeps the level relatively constant and excretes any surplus via the kidneys.

What research is investigating

The role of vitamin C as an essential nutrient and co-factor is textbook knowledge and the basis of the approved claims. Beyond that, vitamin C is one of the most intensively researched vitamins of all. Research looks, for example, at how the need for vitamin C changes under particular strain – such as during intense physical exertion, when oxidative turnover rises. Another strand of research deals with the bioavailability of different forms and matrices: does the body absorb vitamin C from a fruit extract differently than pure ascorbic acid? The interplay with other antioxidants such as vitamin E, which can return vitamin C to its active form, is also examined. What is emerging as established is the fundamental, broad function as a nutrient; the precise optimisation of amount and form in everyday life remains the subject of ongoing research.

How much vitamin C per day?

The German Nutrition Society (DGE) recommends about 110 mg per day for men and 95 mg for women for adults. This amount fully covers the needs of healthy adults. An increased requirement applies, among others, to:

• Smokers: here the recommendation is higher (155 mg for men, 135 mg for women), as smoking increases vitamin C turnover.
• Athletes: during intense physical exertion an additional intake is approved – 200 mg in addition to the recommended daily amount contribute to maintaining normal immune function during and after intense physical exercise.
• People with a one-sided diet or little fresh fruit and vegetables.

In principle, the requirement can be well covered through a normal diet – even a single red bell pepper or a handful of berries provides considerable amounts. A dietary supplement can make sense when intake through food fluctuates or the requirement is increased. How to set up your everyday routine around special situations is shown in Strengthening the immune system in winter.

Natural sources: acerola, rosehip & co.

Vitamin C is found above all in fresh fruit and vegetables. Particularly rich are:

The acerola cherry is one of the richest natural sources of vitamin C of all and is therefore found in many dietary supplements. An important practical note: vitamin C is sensitive to heat, light and oxygen. During long cooking, keeping food warm, cutting it up long in advance or storing it for weeks, some of it is lost – fresh vegetables, raw or gently cooked (briefly and with little water), therefore provide the most. Anyone who steams their vegetables instead of boiling them vigorously and eats them soon afterwards gets noticeably more out of them.

Who should pay particular attention to their intake

In principle, vitamin C is easily obtained through the diet – nevertheless there are life situations in which the supply can start to falter. These include people who permanently eat little fresh fruit and vegetables, for example with a very one-sided diet, a lot of fast food or little appetite. Smokers, too, as mentioned, have an increased turnover. In the cold season, when local fresh fruit becomes scarcer and long storage lowers the content, many deliberately reach for a reliable source. And anyone who does intense exercise has an increased requirement due to the heightened oxidative turnover. In all these cases, targeted supplementation is a simple safeguard – more on this in Nutrients when you eat few vegetables.

Natural or synthetic – which is better?

One of the most frequent questions, and the honest answer is: the molecule ascorbic acid is identical, whether it is obtained from the acerola cherry or produced synthetically. The body can utilise both equally well – there is no proven "efficacy advantage" of pure ascorbic acid from the fruit. The difference lies in the accompanying matrix: natural sources such as acerola bring along secondary plant compounds (such as bioflavonoids) that pure synthetic ascorbic acid does not contain. Anyone who values a product that is as close to nature as possible, with these additional plant compounds, therefore reaches for acerola or fruit extracts. Anyone simply looking for a reliable, inexpensive source of vitamin C is equally well supplied with pure ascorbic acid. The details are explored in depth in Vitamin C: acerola vs. synthetic and, more generally, Synthetic or natural vitamins.

The duo vitamin C and iron

One of the practically most important properties: vitamin C increases iron absorption. Plant-based iron in particular (from pulses, oats or green vegetables) is absorbed less well by the body than animal iron – vitamin C significantly improves this absorption by converting the iron into a more soluble form. A glass of orange juice with your porridge, or the combination of both nutrients in one product, is therefore clever. How to use the duo optimally is shown in Combining vitamin C and iron; more on the topic of iron is provided by Recognising & preventing iron deficiency. Vitamin C also plays a role for a strong immune system.

Intake, timing & tolerability

Because vitamin C is water-soluble and is not stored, it makes sense to spread larger amounts over the day rather than taking everything at once – this keeps absorption more even. A fixed time (such as in the morning) is not essential; regularity is more important. Taken with an iron-rich meal, it additionally supports iron absorption. All timing questions are addressed in Vitamin C: when to take it?, and the choice of form in Vitamin C: powder or capsules.

Vitamin C is considered very well tolerated. Very high single doses (well above 1,000 mg) can cause gastrointestinal discomfort in sensitive people. Anyone prone to kidney stones should clarify high dosages with a doctor beforehand. How much stays within reason is put into context by Vitamin C in high doses: how much?.

Honestly assessed: what is established and what is not

What is established is the broad function of vitamin C as an essential nutrient – the numerous approved claims stand for this. Equally clear: anyone who is already well supplied gains no automatic added benefit from additional amounts; the body regulates the level. Popular notions that very high doses would generally "charge up" health miss this regulatory mechanism. Vitamin C is useful where intake through food fluctuates, the requirement is increased or you specifically want to support iron absorption. Viewed this way, it is a reliable, well-tolerated basic nutrient – with clear strengths and without any miracle expectations.

Suitable products from Scheunengut

In the Vitamin C category you will find acerola preparations, buffered variants as well as capsules and powder. For the interplay with iron, it is worth taking a look at the Iron category; a broader overview is provided by Vitamins and Immune system. As further reading, Combining vitamin C and iron, Vitamin C: when to take it?, Vitamin C deficiency: signs and What are antioxidants? all fit well.

Frequently asked questions (FAQ)

How much vitamin C does an adult need per day?

The DGE recommends around 110 mg per day for men and 95 mg for women. This amount fully covers the needs of healthy adults. Smokers have an increased requirement (155 or 135 mg respectively), as do people with intense physical exertion. Through a varied diet with fresh fruit and vegetables, the requirement can usually be well covered.

Is natural vitamin C from acerola better than synthetic?

The molecule ascorbic acid is chemically identical in both cases, and the body utilises it equally well – there is no proven efficacy advantage of the acerola variant for the vitamin C itself. The difference lies in the accompanying matrix: acerola and other fruit extracts bring along additional secondary plant compounds such as bioflavonoids. Anyone who values these chooses acerola; anyone looking for an inexpensive, reliable source is well supplied with pure ascorbic acid.

Can you take too much vitamin C?

Vitamin C is water-soluble, and the body excretes any surplus via the kidneys, which is why it is considered very well tolerated. Very high single doses well above 1,000 mg can cause gastrointestinal discomfort in sensitive people. Anyone prone to kidney stones should clarify high dosages with a doctor beforehand. For most people, usual amounts are unproblematic.

How do I recognise a vitamin C deficiency?

A pronounced deficiency is rare in industrialised countries, but it can show up through tiredness, poorer wound healing, sensitive gums and an increased susceptibility to infections, as vitamin C is important for collagen formation and immune function. Risk factors are a very one-sided diet, little fresh fruit and vegetables as well as smoking. If there is a suspicion and persistent complaints, the cause should be clarified by a doctor.