Tin is a metal that is almost non-toxic in its pure form and in its inorganic compounds. However, individual organic compounds have a toxic effect and are used in fungicides, for example. Tin was already being used in ancient China several thousand years before Christ. It was probably also known in the ancient civilizations of India, Egypt, Phoenicia and ancient Rome. Tin is used in industry to produce tinplate, for example for tin cans. In art, it is used for bronze sculptures and in dyes. In food, the tin content depends on the soil and vegetation, and deposits vary.
Tin is possibly an essential trace element for humans. It is found in almost all organs, especially in the gastrointestinal tract, liver and lungs. The functions of tin in humans are still not exactly known. It is assumed that tin is involved in the body's own decomposition and oxidation processes (redox systems) and in the metabolism of proteins. It may also be involved in the tissue hormone gastrin, which regulates the formation of hydrochloric acid in the stomach. Symptoms of deficiency are unknown in humans. There are indications from animal experiments that a tin deficiency retards growth.
A daily requirement value has not yet been specified for tin. The average daily intake is estimated, with values ranging from around 3 to 14 milligrams of tin. Presumably only very small amounts of tin are absorbed in the body. Tin can also be dissolved out of can walls or tin dishes. In this way, excessive intakes are possible, especially from canned fruit juices and sour preserves. Zinc poisoning has been described, for example in the processing of metals, the manufacture of plastics and pest control.
