Water-soluble vitamins: definition & explanations

Wasserlösliche Vitamine: Definition & Erklärungen

In nutrition, one often speaks of water-soluble vitamins. But what does that mean and what is the difference to the fat-soluble vitamins? How do I know if I'm getting enough vitamins and in which foods are water-soluble vitamins even available?

We answer these and other questions in this article on the subject of water-soluble vitamins. So if you've always wanted to learn more about this nutritional subject, but don't want to torment yourself through complicated studies and textbooks, you've come to the right place.

the essentials in brief

  • All vitamins are either water-soluble or fat-soluble. The key factor, as the name suggests, is solubility.
  • The water-soluble vitamins include all vitamins of the B group, as well as vitamin C. In contrast to the fat-soluble vitamins, they cannot be stored by the body and must therefore be regularly ingested with food.
  • The water-soluble vitamins fulfill many essential functions in the human body, among other things they are important for the metabolism, cell renewal and the immune system.

Glossary entry: The term water-soluble vitamins explained in detail

So that you are fully informed, in the following paragraphs we have taken up the most important questions on the subject of land charge order deeds and answered them in detail. So nothing should remain unclear and you should become an expert in the field of water-soluble vitamins.

What are water soluble vitamins?

Within the group of vitamins, of which 13 are known today, a distinction can be made between water-soluble and fat-soluble vitamins. The main point of demarcation is the fact of how the respective vitamins can be absorbed, transported, stored and excreted by the body.

citrus fruits

The best-known vitamin in the water-soluble category is vitamin C. This can be found in sufficient quantities in citrus fruits in particular. (Image source: Bruna Branco / unsplash)

The water-soluble vitamins dissolve in water and are absorbed by the body through the small intestine. Surpluses are mostly excreted with the stool because the body cannot store water-soluble vitamins or only in very small doses. It is therefore of great importance that the supply of these vitamins takes place on a regular basis, otherwise undersupply and further deficiency can occur. (1)

The body can only store vitamin B12 in very small amounts and therefore has a small depot available, which it can fall back on in the event of a supply shortage.

Which vitamins are water soluble?

Water-soluble vitamins include:

  • Vitamin B1 (thiamine)
  • Vitamin B2 (Riboflavin)
  • Vitamin B3 (Niacin)
  • Vitamin B5 (pantothenic acid)
  • Vitamin B6 (pyridoxine)
  • Vitamin B7 (biotin)
  • folic acid
  • Vitamin B12 (cobalamin)
  • Vitamin C (ascorbic acid)

All vitamins not mentioned here are therefore among the fat-soluble vitamins. These are: vitamin A (retinol), vitamin D (cholecalciferol), vitamin E (tocopherol) and vitamin K (phylloquinone). They need fat as a transport medium for the body to use, but can be stored by the body. (2)

What foods contain water-soluble vitamins?

Water-soluble vitamins are found in sufficient amounts in everyday foods. Anyone who has a healthy, balanced diet should therefore be supplied with all vitamins without any problems. The following table shows which foods contain particularly large amounts of the respective water-soluble vitamins.

vitamin intake through food
B1 (Whole grain) cereals, nuts, potatoes, legumes, pork, brewer's yeast
B2 Eggs, dairy products, mushrooms, meat, fish, offal, nuts, legumes
B3 Meat, fish, whole grains, milk, coffee, peanuts, legumes
B5 Yeast, egg, whole milk, nuts, mushrooms, meat, fish, butter, legumes, broccoli
B6 Fish, meat, potatoes, legumes, bananas, carrots, nuts
B7 Meat, whole milk, egg, nuts, legumes, oatmeal, yeast
B12 Fish, meat, whole milk, cheese, fermented plant foods
folic acid Meat, legumes, lettuce, spinach, Brussels sprouts, broccoli, yeast
C Black currants, sea buckthorn, acerola juice, bell peppers, broccoli, Brussels sprouts and kale

Vitamins are sensitive to sunlight, heat and oxygen. We therefore recommend that you choose freshly harvested fruit and vegetables. It is best to store it in a cool, dark place and use it up within a few days.

Which water-soluble vitamins does the body need and in what dosage?

Below you will find reference values ​​from the German Society for Nutrition. This is the minimum dosage that a healthy adult should consume per day. (3)

vitamin dosage/day
B1 1.0 to 1.5 mg
B2 1.6 to 2 mg
B3 16 to 20 mg
B5 18 to 20mg
B6 1.6 to 2 mg
B7 60 to 300 mcg
B12 3 to 6 mcg
folic acid 300 to 400 mcg
C 95 to 110 mg

As previously mentioned, the most significant difference between water and fat soluble vitamins is that the human body cannot store water soluble vitamins and excess is simply excreted. This also means that overdosing is virtually impossible.

An overdose is only possible if the recommended daily dose is massively exceeded by taking food supplements. (4)

What is the function of water-soluble vitamins?

Water-soluble vitamins enter the blood via the intestine. There they already fulfill their first tasks. These are sometimes:

  • Strengthening of skin, connective tissue and nerves
  • Support of the immune system
  • detoxification of the body
  • function of metabolism
  • Promoting the absorption of minerals from food (1)

You can read off other tasks of the individual water-soluble vitamins in the following table.

vitamin function
B1 Energy metabolism, nervous system
B2 Energy production, tissue formation
B3 Antioxidant, lipid metabolism, cell metabolism
B5 Protein and fat synthesis, energy production
B6 Blood sugar regulation, synthesis of neurotransmitters, metabolism
B7 Fat metabolism, cell growth, synthesis of glucose
B12 Structure of nerve cells, cell development, blood formation
folic acid Cell growth, blood formation, protein metabolism
C Protection of body cells, defense against infection, development of connective tissue, cartilage, bones and teeth

What are the effects of a lack of water-soluble vitamins?

Basically, with a healthy, varied and balanced diet, there is hardly any risk of a deficiency. Of course, this does not apply if the need is increased, such as during pregnancy or certain illnesses.

Since a defect can have serious consequences, it is essential to avoid it. It can promote the development of certain diseases and also weaken the immune system. (5)

We recommend that you have your blood values ​​tested regularly to ensure an optimal supply of all important nutrients and vitamins.


Water-soluble vitamins (B and C vitamins) differ from fat-soluble vitamins (vitamins D, E and K) in that they are found in body fluids such as blood and are not stored by the body but are simply excreted in excess. As a result, an excess is usually impossible. They can normally be supplied in sufficient quantities through a balanced diet and are responsible for a number of important functions in the body.


  1. https://www.eunova.de (2020): Water-soluble vitamins: essential nutrients for the body.
  2. https://www.cancer.gov (2020): Water-soluble Vitamin: Definition.
  3. https://www.dge.de (2020): Reference values ​​for nutrient intake. German Society for Nutrition.
  4. National Research Council (1989): Recommended Dietary Allowances: 10th Edition.
  5. National Research Council (1989) Diet and Health: Implications for Reducing Chronic Disease Risk.
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