Vitamin C is not only found in fruit and vegetables

Vitamin C is a water-soluble vitamin; its chemical name is ascorbic acid. Of the four chemical forms of ascorbic acid, only L-ascorbic acid is biologically active. Chemical derivatives of L-ascorbic acid can be converted into L-ascorbic acid in the body. These also fall under the collective term vitamin C.

Unlike most animals, humans cannot produce vitamin C themselves, but must take it up from food. The vitamin is essential for life and is involved in numerous metabolic processes. For example, it is needed for the formation of connective tissue (collagen), wound healing and the immune system.

Vitamin C is involved in numerous metabolic processes. It is probably best known for its role in immune defence – an adequate supply of this vitamin is essential for the normal functioning of the immune system.

As vitamin C has antioxidant properties, together with the other antioxidant vitamins E and A, as well as carotenoids, it is involved in the reduction of reactive oxygen species in the body, thereby protecting cells and molecules from oxidative damage.

Vitamin C also plays a central role in wound healing and the formation of connective tissue, or more precisely, in the formation of collagen, an important protein in connective tissue. In this function, it is also essential for healthy teeth and bones. Finally, vitamin C supports the intake of iron from plant-based foods.

Vitamin C is found in many foods; data from the National Food Consumption Survey II show that the population in Germany obtains most of its vitamin C from fruit. Non-alcoholic beverages and vegetables follow in second and third place. According to the German Nutrition Society (DGE), red peppers and blackcurrants are among the foods with very high content of vitamin C: 100 grams (g) of red peppers contain 140 milligrams (mgshort formilligram) of vitamin C – more than an adult’s daily requirement. It should be noted that the content of vitamin C in food decreases when exposed to light during storage or when heated to high temperatures.

Vitamin C or ascorbic acid is also found in many processed foods: it is added to these as an antioxidant, for example to preserve vegetables, jam, meat or sausages, or as a stabiliser, e. g. to refine the properties of flour. In sausages such as salami or cooked sausages, ascorbic acid is added to preserve the product and to support reddening – a technological process used to maintain the red colour of the meat.  Vitamin C added to food for technological purposes is listed in the ingredient lists of packaged foods as "ascorbic acid" or E 300.

In addition to foods that naturally contain vitamin C or to which it is added for technological purposes, there are also foods to which vitamin C is added for nutritional purposes. These so-called fortified foods include juices, for example. There are also many food supplements containing vitamin C.

In the European Union and also in Germany, there are currently no regulations stipulating maximum amounts of vitamin C that may be used in food supplements or for the fortification of foods. The German Federal Institute for Risk Assessment (BfRshort forGerman Federal Institute for Risk Assessment) has proposed maximum amounts for the addition of vitamin C, as well as all other vitamins and minerals, to food supplements and for fortified foods.

Ascorbic acid used in food for technological or nutritional purposes performs the same functions in the body as naturally occurring vitamin C.

However, vitamin C supplements and processed or fortified foods generally lack the numerous other substances that normally occur together with vitamin C in plant-based foods and are also important for healthy nutrition, such as secondary plant substances or enzymes.

Vitamin C is not only found in food, but also in many cosmetic products, such as lotions, serums and hair dyes. Among other things, it is said to stimulate connective tissue metabolism and thus counteract skin ageing. This is because vitamin C is involved in the synthesis of collagen, an important protein in connective tissue.

Vitamin C also acts as an antioxidant in the body. This means that it acts as a scavenger for harmful compounds such as reactive oxygen species. This protects cells and molecules and also helps maintain healthy skin. Finally, it is said to brighten the skin and help reduce pigmentation spots. This effect is due to the ability of vitamin C to inhibit the enzyme tyrosinase, which in turn is involved in the formation of the skin pigment melanin.

When vitamin C is added as an ingredient to cosmetic products, it is subject to the safety assessment required for cosmetics. Consumers can therefore assume that cosmetics containing vitamin C are not harmful to health. Most of the vitamin C in cosmetics is not taken up by the body but is metabolised in the skin.

How much vitamin C a person needs, depends on age and gender. According to the German and Austrian Societies for Nutrition, adult men and women should take up 110 and 95 mgshort formilligram per day respectively. The requirement increases during pregnancy and breastfeeding. The intake recommendations for all (age) groups can be found at the DGE.

Consumption studies show that vitamin C intake in Germany exceeds the intake recommendations of the German Nutrition Society (DGE) and the Austrian Nutrition Society (ÖGE) in all age groups of the population: According to the Food Consumption Survey II, the median of adult men and women (aged 19 to 80) take up around 130 mgshort formilligram of vitamin C per day through their diet. The median intake in children and adolescents is also above the reference values, which shows that the recommended intake levels are easily achieved through the dietary habits typical in Germany.

According to the DGE, smokers, for example, have an increased requirement: they should take up 135 mgshort formilligram (women) or 155 mgshort formilligram (men) of vitamin C per day. Vitamin C requirements are also increased during pregnancy because the growing unborn child utilises parts of the maternal vitamin C reserves. During breastfeeding, the mother passes on vitamin C through her breast milk. For these reasons, pregnant women should take up 105 mgshort formilligram daily from the fourth month of pregnancy onwards, and breastfeeding women 125 mgshort formilligram daily. These recommendations are also easy to achieve through a balanced diet.

Well into the 19th century, sailors often suffered from scurvy, a disease caused by severe deficiency of vitamin C, because fresh fruit and vegetables were not available on long sea voyages. Nowadays, scurvy and such a pronounced vitamin C deficiency are virtually non-existent in industrialised countries. At most, people who have a very unbalanced diet and eat little or no fruit and vegetables and/or are smokers may be insufficiently supplied with vitamin C. This initially manifests itself in fatigue, a weakened immune system or muscle pain. Later, it can lead to bleeding gums, wound healing disorders and joint pain, among other things. However, vitamin C deficiency is extremely rare in Germany.

Based on current knowledge, vitamin C is generally considered to be a vitamin with low toxicity, as excess amounts are excreted. However, the intake of very high doses (more than three grams) can, however, cause gastrointestinal discomfort and diarrhoea. Some people are at increased risk of adverse effects from long-term high vitamin C intake, especially those who have a higher risk of developing kidney stones due to due to medical conditions.

With regard to the intake of vitamin C via food supplements, based on the available data, the European Food Safety Authority (EFSAshort forEuropean Food Safety Authority) assumes that an additional intake – i.e. beyond the amount obtained from food – of up to 1,000 mgshort formilligram (equivalent to 1 g) of vitamin C per day has no adverse effects on the gastrointestinal tract. However, larger amounts increase the risk of adverse gastrointestinal effects. According to EFSAshort forEuropean Food Safety Authority, even a habitual intake of 1,500 mgshort formilligram of vitamin C per day does not increase the risk of kidney stones.

Since vitamin C promotes iron absorption in the intestine, people with haemochromatosis – a genetic disorder that leads to undesirably high iron absorption and storage – have an increased risk of iron overload when taking high-dose vitamin C supplements.

However, in cases of iron overload or when metal ions are released locally due to cell lesions (e.g. as a result of atherosclerosis or rheumatoid arthritis), vitamin C can also have a pro-oxidative effect. This can lead to damage to tissue components. The risk of this is increased in people who already have a good supply of vitamin C in their nutrition and also take high-dose vitamin C supplements.

The BfRshort forGerman Federal Institute for Risk Assessment is therefore of the opinion that the amount of vitamin C, as with most other vitamins, should be limited in food supplements and fortified foods (see the BfRshort forGerman Federal Institute for Risk Assessment's External Link:updated maximum levels for vitamins and minerals in food supplements and fortified foods).

As a rule of thumb, a balanced and varied diet provides healthy people with sufficient amounts of essential nutrients. Food supplements are therefore generally unnecessary for healthy individuals who follow a balanced diet. Conversely, an unbalanced diet cannot be compensated for by taking food supplements. For vitamin C, the data available for Germany show that the population as a whole takes up sufficient amounts through food.

According to current knowledge, increased intake of vitamin C beyond requirements does not confer any health benefits. Furthermore, scientific studies have not yet been able to prove that additional vitamin C intake, e.g. via food supplements, protects the well-nourished and otherwise healthy general population from colds.

Given that excessive intake of vitamins and minerals can have adverse effects on health, Regulation (EC) No 1925/2006 (Regulation on the addition of vitamins and minerals and of certain other substances to foods) and Directive 2002/46/EC (on the approximation of the laws of the Member States relating to food supplements) provide for the establishment of maximum amounts for vitamins and minerals in these products. These amounts are intended to ensure that the normal consumption of these foods is safe for consumers. However, no binding maximum levels have been set at either national or European level to date. This also applies to vitamin C.

The BfRshort forGerman Federal Institute for Risk Assessment had already proposed maximum levels for vitamins and minerals in food supplements and fortified foods in 2004, which were updated in 2021. The maximum levels proposed by the BfRshort forGerman Federal Institute for Risk Assessment are intended to serve as a basis for setting up maximum amounts at EU level.

The BfRshort forGerman Federal Institute for Risk Assessment's recommendations for maximum levels can be External Link:viewed here. They aim to limit the nutrient intake via food supplements and fortified foods in such a way that the consumption of these products provides a significant additional intake while at the same time protecting the majority of the well-nourished population from excessive intake. You can also find more information on food supplements in our FAQ.

In order to enable consumers to obtain additional nutrients via food supplements, if necessary, while at the same time protecting well-nourished people from excessive intake, the External Link:BfR recommends a maximum amount of 250 mgshort formilligram of vitamin C per daily dose of a food supplement.

The BfRshort forGerman Federal Institute for Risk Assessment has also derived maximum amounts for vitamin C in fortified foods: Assuming that consumers obtain 30 per cent of their daily energy intake from fortified foods, the BfRshort forGerman Federal Institute for Risk Assessment recommends maximum amounts of 60 mgshort formilligram of vitamin C per 100 g for solid foods and 16 mgshort formilligram per 100 millilitres (mlshort formillilitre) for beverages.