Vitamins take over vital functions in our body, but for the most part cannot be produced by the body itself. We take in some vitamins as provitamins, which are later converted into the active form in our body (for example, beta-carotene becomes vitamin A). There are 13 vitamins in our body – 4 fat-soluble and 9 water-soluble.
Due to their chemical structure, vitamins E, D, K and A are easily soluble in fats. Therefore we find them in our food only in fatty foods. With the exception of vitamin K, they can be stored in larger quantities in the body (liver, depot fat). Short-term intake deficits can be compensated. Fat-soluble vitamins are involved in protein synthesis.
Vitamin C, the B vitamins and folic acid use water as a solvent. With the exception of vitamin B12, they cannot be stored in large quantities by the body. The body can therefore not compensate for a lack of supply for long. Water-soluble vitamins become co-enzymes in the body, the so-called “helpers of enzymes”.
Vitamin supply in Germany
Germany is not a vitamin deficiency country – only the vitamin D supply and the folic acid intake is insufficient in large parts of the population. Lighter forms of vitamin deficiency are known as hypovitaminosis, more severe as avitaminosis. They are mostly caused by malnutrition, resorption disorders (severe diarrhoea) or by destruction of the intestinal flora (e.g. by antibiotics). In the following, a selection of vitamins will be examined in more detail.
Vitamins A, C, E – the antioxidants
In metabolism, free radicals (oxygen radicals) are continuously produced. Free radicals are an important signal generator for adaptation processes, but can also lead to damaging chain reactions. These chain reactions lead to cell damage and are causally responsible for cancer and ageing processes. Antioxidants such as vitamins A, C and E are able to “intercept” and neutralize free radicals.
Vitamin A – The “eye vitamin
Vitamin A is an indispensable component of the visual process. It is also an antioxidant and radical scavenger and thus a protective factor for the skin and mucous membranes. Vitamin A only occurs in animal foods, but can be formed from the precursor beta-carotene, which occurs in plant foods. Sources of vitamin A are liver, liver sausage, tuna, egg yolk, dairy products, carrots, spinach, pumpkin and apricots. An overdose of vitamin A can have health consequences. Symptoms of overdose include headache, nausea and vomiting, peeling skin and redness of the mucous membranes. [LINK – Article Carrots make good eyes]
Vitamin C – ascorbic acid
Vitamin C is a radical scavenger and antioxidant. It contributes to the support of the immune function and to the connective tissue structure. Sources of vitamin C are citrus fruits, acerola cherries, black currants, sea buckthorn, broccoli, paprika, potatoes and cabbage. Vitamin C is often used in the food industry as a preservative (ascorbic acid). Iron uptake from food is controlled by vitamin C
is promoted. Symptoms of deficiency include fatigue, susceptibility to infections and scurvy.
Vitamin C deficiency – scurvy
Scurvy is referred to as the seafarer’s disease because it used to spread among seafarers and was often their frequent cause of death. Scurvy is caused by a vitamin C deficiency after about 2-4 months. The symptoms are bleeding gums, poor wound healing, muscle atrophy and high fever. In 1754 the ship’s doctor James Lind recognized that scurvy could be cured with citrus fruits. Scurvy no longer occurs in modern civilisation societies.
Vitamin E acts as a radical scavenger and antioxidant in cell membranes by preventing the destruction of cell walls. Due to its antioxidant properties, vitamin E is important for athletes to reduce stress induced tissue damage. The vitamins are said to intercept radicals. An early symptom of a vitamin E deficiency is a shortened lifespan of the red blood cells, the so-called haemolysis tendency. Good sources of vitamin E are vegetable oils, nuts, soybeans and eggs.
Vitamin supply via pills?
A varied diet usually ensures an adequate supply of vitamins. Nevertheless, about one in three people in Germany consumes vitamin supplements. However, vitamin supplements are only recommended in certain situations (such as folic acid for pregnant women). Since some vitamins may be overdosed (e.g. vitamin A), they should not be consumed in excessive quantities.