Vitamin C – effects, left-handedness of vitamin C

Vitamin C is one of the most recognisable ingredients in supplements and fortified foods. It is mainly associated with the autumn and winter seasons, citrus fruits and effervescent tablets, but its importance is much broader. It is a well-described biochemical compound, present in many metabolic processes and, at the same time, extremely susceptible to simplification. This is precisely why so many myths have arisen around vitamin C: about the ‘strongest’ forms, about its alleged left-handedness, about huge doses, and about the fact that each vitamin C works completely differently.

1. Vitamin C – a realistic view
2. What is vitamin C?
3. The effects of vitamin C
4. Vitamin C in your daily diet
5. Dosage
6. The left-handedness of vitamin C – where did this myth come from?
7. Ascorbic acid, sodium ascorbate, acerola, liposomal – are they really different worlds?
8. What to remember and implement

Vitamin C – a realistic view

If we look at the issue calmly, vitamin C does not need legends. Its role in the body is interesting enough. It is a water-soluble vitamin that humans cannot synthesise themselves, so it must be supplied through diet. In the European Union, the reference value for vitamin C labelling is 80 mg, but supplements containing 200, 500, 1000 mg or more per serving are readily available on the market.

What is vitamin C?

Ascorbic acid and ascorbates

Vitamin C is the name of a vitamin whose basic chemical form is L-ascorbic acid. In food and supplements, it can occur both as ascorbic acid and in the form of salts, i.e. ascorbates, for example sodium or calcium. We are still talking about vitamin C, only in a different chemical form of the raw material. This is important because different trade names often appear on labels, but in practice the starting point is the same: the product provides vitamin C, only in a different technological form.

A vitamin that we do not produce ourselves

Humans, like other primates and several other species, do not synthesise vitamin C themselves. This means that it must be obtained from food. Its main sources are vegetables and fruit, but dietary supplements, shots, powders, capsules, effervescent tablets and preparations combined with bioflavonoids or plant extracts have also been available on the market for a long time. However, the mere presence of supplements does not mean that vitamin C is a ‘rare’ ingredient. On the contrary, it is widely present in a normal diet, but very often it is not noticed until you start looking for it on the label.

The effects of vitamin C

The most important functions that are really worth remembering

Vitamin C contributes to the normal functioning of the immune system, to the protection of cells from oxidative stress, to the reduction of tiredness and fatigue, and to normal energy metabolism. These are not loose associations from the internet, but well-established directions in European statements for vitamin C. In practice, this means that vitamin C is not associated with just one area, but with several basic physiological processes at the same time.

Its role in the normal synthesis of collagen is also very important. This is why vitamin C appears in the description of the normal functioning of blood vessels, bones, cartilage, gums, skin and teeth. Here, it is clear how much vitamin C goes beyond the stereotype of an "autumn tablet". From a biochemical point of view, it is a cofactor for enzymes involved in collagen synthesis, and thus plays a role in something much more fundamental than just seasonal associations with the chemist's.

An additional practical benefit

Vitamin C increases iron absorption. This is one of those points that are very useful in everyday practice, yet often get lost under a layer of more catchy marketing slogans. If you look closely at the labels, you will quickly notice that vitamin C is very often combined with iron-containing preparations or appears alongside plant ingredients that are naturally rich in this compound.

Vitamin C in your daily diet

Where can you find it?

The most well-known sources of vitamin C are citrus fruits, kiwis, strawberries, blackcurrants and vegetables such as peppers, broccoli, Brussels sprouts and potatoes. In practice, many people are surprised by the fact that it is not always lemons that are the leaders, but often peppers or blackcurrants, which score very well per 100 g of product. This is one of the most interesting differences between perception and reality: vitamin C is strongly associated with citrus fruits, but a normal diet can provide it from completely different products.

Culinary curiosity

Vitamin C is a relatively unstable compound. Losses can increase with prolonged storage, high temperatures, light and contact with water. Therefore, raw vegetables and fruit or shorter heat treatment usually protect the vitamin C content better than long cooking. This is very practical information: sometimes the way food is prepared and stored is more important than simply buying a "product with vitamin C".

Dosage

What does 100% RDA mean?

On labels in the European Union, 100% of the reference intake for vitamin C corresponds to 80 mg. This means that a supplement containing 1000 mg provides a multiple of this value. This does not automatically mean that a higher number of milligrams always means a ‘better’ product. In practice, many preparations build their appeal mainly on the high number on the front of the packaging, rather than on the actual needs of the user.

More does not always mean better

Large amounts of vitamin C are not stored in the body in the same way as fat-soluble vitamins. At the same time, very high supplement doses may cause gastrointestinal discomfort in some people. The NHS reports that amounts exceeding 1000 mg per day can cause abdominal pain, diarrhoea and flatulence. In practice, this means that a ‘mega dose’ is not a neutral ritual for everyone just because vitamin C is common and well known.

The left-handedness of vitamin C – where did this myth come from?

"L" does not mean “levorotatory”

This is one of the most persistent myths in Polish supplementation. The biologically active form of vitamin C is L-ascorbic acid, but the letter L in this notation does not mean that the compound is ‘levorotatory’ in the colloquial marketing sense. The D/L designations describe the stereochemical configuration of the molecule, while the direction of rotation of the light plane is described by a different system, namely the (+)/(−) signs. These are two different naming systems, which have been mixed up in commercial circulation over the years.

What is really important?

The most important thing is that vitamin C in the nutritional sense is the L-ascorbic form. There is no need to add the word ‘levorotatory’ for the product to be valuable. This slogan has become popular mainly because it sounds scientific and makes the packaging stand out, but in itself it does not say anything useful about quality. The composition, the amount of vitamin C per serving, the form of the raw material and any additives, such as bioflavonoids or a buffered form, say much more.

Ascorbic acid, sodium ascorbate, acerola, liposomal – are they really different worlds?

Chemical form and marketing

Ascorbic acid is the basic, classic form of vitamin C. Sodium ascorbate and calcium ascorbate are its salts. Acerola and rosehip are plant materials that contain natural vitamin C, often along with other plant compounds. On the other hand, products described as liposomal try to stand out with their carrier technology. In practice, different forms may vary in terms of convenience of use, taste, auxiliary composition and price, but this does not change the fact that we are talking about vitamin C as a nutrient, not several completely different vitamins.

How to choose wisely?

If a product has a simple composition, a clearly stated amount of vitamin C and chemical form, that's already a lot. In practice, the most common mistake is that the choice is based on the slogan on the front of the packaging rather than the composition table. With vitamin C, you often don't need the ‘most advanced’ version. Sometimes a transparent product without excessive narrative is simply better.

Vitamin C deficiency

Extreme, long-term vitamin C deficiency leads to scurvy. Today, this is a rare occurrence, but it clearly shows that vitamin C is not a cosmetic addition to the diet, but a truly necessary component. The body does not produce it itself, so a chronic undersupply affects basic bodily functions. In everyday life, a deficiency does not necessarily have to start with a historical image from a textbook, but the very fact that scurvy exists reminds us that vitamin C is an essential vitamin, not an ‘optional’ one.

What to remember and implement

Vitamin C is primarily L-ascorbic acid and its derivatives, a compound that the human body does not produce on its own and must be regularly supplied through diet. Its presence in the daily menu is important not only because it is well known, but because it participates in several basic physiological processes. Vitamin C contributes to the proper functioning of the immune system, proper collagen synthesis, protection of cells from oxidative stress, reduction of tiredness and fatigue, and increases iron absorption. In practice, this means that there is no need to build a legend around it, because its role in the body is important enough on its own.

It is also worth remembering that vitamin C is widely present in everyday foods. Good sources include not only citrus fruits, but also peppers, blackcurrants, kiwis and broccoli. At the same time, it is a relatively sensitive compound, so long storage and intensive heat treatment can reduce its content in food. In supplements, the most controversial concept is "left-handed vitamin C", which functions more as a marketing simplification than a real product advantage.

The composition, chemical form and amount of vitamin C in a serving say much more than a catchy slogan on the front of the package. Similarly, a higher dose does not automatically mean a better choice, as very large amounts can cause gastrointestinal discomfort. That is why the most sensible approach to vitamin C is not based on trendy slogans, but on calmly reading the label and understanding what this ingredient really is. 

Sources:

• Vitamin C: A Comprehensive Review of Its Role in Health, Disease Prevention, and Therapeutic Potential https://pubmed.ncbi.nlm.nih.gov/39942850/
• Vitamin C and Immune Function https://pubmed.ncbi.nlm.nih.gov/29099763/
• Vitamin C: From nutrition to oxygen sensing and epigenetics https://pubmed.ncbi.nlm.nih.gov/37263060/