Phosphorus

Phosphorus is a non-metallic element and has the atomic number 15 in the periodic table of elements. Its chemical symbol is P. The name phosphorus is derived from the Greek " φως-φορος " and means "light carrier". Phosphorus does not occur in nature in elemental form, but only in the form of phosphates, which are organic or inorganic oxygen-containing compounds. Due to the different arrangement of the atoms, elemental phosphorus occurs in principle in four modifications: white or yellow toxic phosphorus, red, black and violet phosphorus. White phosphorus can be obtained from the ore of apatite (Ca-F-Cl-phosphate), which has a particularly high phosphorus content. Red phosphorus, an amorphous powder, is produced by prolonged heating of the white phosphorus above 250° C; with even longer heating, this turns into crystalline violet phosphorus. By using high temperatures and high pressure, black phosphorus can be obtained from white phosphorus. White phosphorus glows in the dark, hence the term phosphorescence. This glowing effect is the result of chemiluminescence, whereby the P2O3 formed on the surface with the air is converted into the lower-energy and more stable P2O5. During this oxidation process, the energy released is emitted in the form of light (and heat). Above 50°C, white phosphorus ignites spontaneously and burns with a yellowish-white and relatively bright flame, which is why white phosphorus must never be stored in the air. Burning white phosphorus is very difficult to extinguish and causes severe burns to human skin. The victims of phosphorus incendiary bombs are terrible examples of this. In contrast, red phosphorus only ignites at temperatures above 300° C. In industry, red phosphorus is used for matches and fireworks. White phosphorus is mainly used to produce phosphates for detergents and fertilizers. As far as is known, phosphorus was discovered in our culture by the alchemist Henning Brand (probably 1630-1710) from Hamburg in 1669. In keeping with the spirit of the times, he was looking for a "philosopher's stone" that would transform base metals into silver. Incidentally, he found phosphorus through intensive distillation of human urine. The identification of phosphorus as a chemical element is attributed to the Berlin chemist Andreas Sigismund Marggraf (1709-1782) in 1743 and Antoine Laurent de Lavoisier (1743-1794) in 1772. Incidentally, the gifted chemist Lavoisier was beheaded during the French Revolution on May 8, 1794. An adult's body contains around 700 g of phosphorus in organic compounds, the majority of which is found in bones and teeth. Phosphorus is an essential mineral for the human organism.

Metabolism

The phosphate ingested with food in the form of organic phosphorus compounds is broken down into inorganic phosphate with the help of enzymes. Up to 70% of the extracted mineral is absorbed in the small intestine (absorption = uptake into the bloodstream). 60 - 80% of the phosphate is excreted via the kidneys and 20 - 40% via the stool. In addition, a small amount of phosphorus is also excreted through sweat. Together with iron, aluminum and calcium,phosphorus forms insoluble salts. The absorption of phosphorus can therefore be impaired by a simultaneous, high intake of these minerals. Phosphate from cereals is present in the form of phytic acid. It can only be utilized by the human organism if the phytin is broken down by the phytases (enzymes) also found in cereals. The activation of phytases is triggered during germination (see also: sprouted grains) in sourdough. With other types of dough, the dough management plays a decisive role in the activation of phytases. Functions in the body Phosphorus is found in the human body as phosphate and is responsible for the entire metabolism: it serves as a building material in bones and teeth. Together with calcium, it is incorporated there in the form of hydroxyapatite. Phosphorus is primarily required in the energy metabolism for the synthesis of phosphates in the ATP (adenosine triphosphate) molecule. ATP is the "currency" of energy in the body, i.e. the form in which energy can be used by the cells after metabolism. As a phosphate, it is also a component of DNA and RNA. Phospholipids are an important component of cell membranes. It increases the conversion rate of the thyroid hormone T4 into T3.

Occurrence

Phosphate is found in practically all foods. However, it is mainly found in protein-rich foods such as milk, meat, fish and eggs. In the form of polyphosphates (linearly linked, condensed phosphates), phosphates are used as food additives in the food industry. They are used, for example, to soften water, as melting salt for processed cheese or in the production of cooked sausages, surimi or fish sticks. The phosphate content of cola-based drinks is also very high. Examples of good sources of phosphorus are hard cheese with 840 mg/100 g and beans with 420 mg /100 g.

Phosphorus deficiency

In children, a phosphorus deficiency results in delayed growth, poor bone and tooth formation and rickets. The symptoms are similar to calcium and vitamin D deficiency. Phosphorus deficiency can lead to weight loss and fatigue at any age. Abnormal appetite (strong craving for phosphorus-containing substances that are not food - chalk, clay, lime, etc.) is also one of the symptoms. A lack of phosphorus can remain hidden for a long time, as phosphorus is mobilized from the bones, i.e. broken down. This was also observed during the war and post-war years. After a prolonged reduction in the intake of phosphate, so-called 'starvation bone softening' occurred. Taking too much calcium and too little phosphorus can lead to the formation of kidney stones. Animal experiments show that, in addition to the weight loss already mentioned, phosphorus deficiency can lead to inadequate skeletal development and, in extreme cases, to death due to loss of strength.

Overdose and poisoning

An excessively high phosphate content in the diet leads to impaired absorption of other minerals and trace elements. Calcium deficiency is particularly common. For example, the drink Coca Cola contains very high concentrations of phosphate and should therefore only be consumed to a limited extent, especially by children and young people. Phosphorus as an element and in a number of compounds is sometimes toxic. White phosphorus, which, as already mentioned, causes burns and severe skin damage on the skin, is considered particularly toxic. When ingested orally, i.e. via the mouth, it causes pain in the stomach area, belching and vomiting, whereby the vomit has a characteristic garlic-like smell and glows on contact with atmospheric oxygen. Diarrhea and a state of shock also occur. If white phosphorus poisoning is survived, liver damage often occurs, which in turn can be fatal. Treatment consists of gastric lavage with a potassium permanganate or copper sulphate solution. Pain and, if necessary, shock must also be treated.

Nutritional requirements

The German Nutrition Society assumes a daily requirement of around 700 mg for adults. As with most minerals, pregnant and breastfeeding women should consume slightly more, around 800 to 900 mg. Growing adolescents should also consume more phosphorus. The phosphorus requirement is covered by a balanced diet, but in the case of some illnesses, such as alcoholism, the amount ingested may not be sufficient.

Requirements in sport

For endurance athletes, an increased intake of phosphates could be worthwhile. Studies have shown that phosphates improve maximum oxygen uptake and thus delay the onset of fatigue during endurance exercise. Even if the causal mechanisms have not yet been clearly clarified, an experiment with phosphates can be recommended to endurance athletes. This involves taking 1g of sodium phosphate 4 times a day in the last 3-4 days before a competition, the last intake should be 2-3 hours before the competition. However, the effects should first be tested during training in order to assess possible intolerance reactions. In my opinion, a daily dose of 2000-4000mg with meals should be sufficient. It should be noted that too high a dosage impairs the calcium and magnesium metabolism, and the ratio of phosphorus to calcium should be 1:1.