Vitamins are essential nutrients that our body is unable to synthesise itself or can do so only to a limited extent. They therefore have to be supplied in our diet. They ensure that a large number of metabolic processes in the body run smoothly. Their functions are manifold and highly varied. Vitamins are important for the synthesis of new cells in your body. They ensure that the nutrients you ingest with your food are utilised, and they are essential for an intact immune system. For example, vitamin C helps fight various pathogens by boosting the immune system, vitamin D strengthens bones and vitamin B1 helps maintain a healthy skin.
There are a total of 13 different vitamins, which are divided into two groups depending on their solubility. The first group contains the water-soluble vitamins. These include all the B vitamins, such as B1, B2, B6, B12, niacin, biotin, pantothenic acid and folic acid, as well as vitamin C. The other group comprises those vitamins that are only soluble in fat, namely vitamins A, D, E and K. Then there are what are known as provitamins, such as beta-carotene, from which the body is able to synthesise vitamin A. These are also fat-soluble. This explains why you should always eat carrots and tomatoes together with some fat, for example a dip containing fat or a slice of bread and butter. Only then is your body able to absorb and utilise the beta-carotene these foods contain.
Vitamins are contained in a wide variety of foods. If you eat a lot of fruit and vegetables, you are supplying your body with vitamin C. Vitamin E occurs, for example, in vegetable oils, and the various B vitamins are found, for instance, in whole-grain products. It is therefore important to eat a varied, balanced diet so that all the vitamins are constantly replenished. But be careful: too much isn't good either. This is particularly true of the fat-soluble vitamins, ie. vitamins A, D, E and K. Unlike the water-soluble vitamins, they can accumulate in the body. A deficiency of vitamins can affect your health. However, this is unlikely to occur if you have a varied diet.
Practical tip: Vitamins are very sensitive. Storing fruit, vegetables and lettuce for long periods in daylight, boiling in large quantities of water and cooking at high temperatures result in the loss of vitamins.