Silica
For historical reasons, silica is a vague term for minerals and sediments with a high silicon content . Originally, this was the name given to minerals which, because of their quartz content, are suitable for the manufacture of glass . However, biogenically formed sediments such as kieselguhr are also referred to as silica: Diatoms have a silicon-containing cell envelope, which is retained after they die and thus forms the silica.
Chemically, silica is a silicic acid anhydride , i.e. silicon dioxide and not silicic acid . Occasionally, aluminosilicates such as kaolins are also referred to as silica. A specialty is the Neuburg Siliceous Earth , which consists of silica and kaolinite and occurs as a sediment of weathered granite rock only near Neuburg an der Donau in Germany.
Health related use
The real silica ( Silicea terra , kieselguhr ) obtained from fossil diatoms is traditionally used as a means of preventing brittle nails and hair and strengthening connective tissue . The application is based on the idea that silicon has a physiological meaning in the human organism, which is considered plausible due to its occurrence in cartilage , bones and connective tissue in particular . Silicon compounds also accumulate in the skin and skin appendages and occur in tooth enamel . In animal experiments, silicates improved the mineralization of bone tissue, and an influence on the formation of cartilage and connective tissue was also shown in animal experiments. Silicon compounds could also play a role in lipid metabolism.
Foods containing silicon include potatoes, high-fiber grains such as barley and oats, root vegetables and beer. Intake recommendations cannot be made due to a lack of data, and deficiency symptoms are not known.
There are various oral preparations on the market that contain silica as a source of silicon. They should strengthen the skin, nails, hair, bones and connective tissue and keep them healthy. An effect of these preparations has not been scientifically proven. 2007 came various silica compounds in the headlines after the Institute of Mineralogy, University of Hamburg and the Federal Institute for Materials Research at on dietary supplements were found to investigations carried out that out of ten studied preparations containing nine crystalline silicon dioxides: Seven consisted primarily of quartz and two from cristobalite in finely ground form. Silicea terra, on the other hand, has an amorphous structure. The consumer protection ministries of several federal states questioned the marketability u. a. on suspicion of consumer deception.
Silica is non-toxic when used orally. With long-term and high-dose intake, the formation of kidney stones containing silicon is possible in individual cases.
As a homeopathic remedy, silica is also known under the name Silicea terra , while silica is known as Acidum silicon .
In cosmetics, silica is used under the name DIATOMACEOUS EARTH ( INCI ).
Individual evidence
- ↑ a b c Entry on silica. In: Römpp Online . Georg Thieme Verlag, accessed on January 2, 2015.
- ↑ Meyers Konversationslexikon. 4th edition, collective of authors, Verlag des Bibliographisches Institut, Leipzig / Vienna 1885–1892.
- ^ J. Göske, W. Kachler: Morphology, Physicochemistry and Phase Analysis of Neuburg Siliceous Earth. In: Microscopy and Analysis 22, No. 5, 2008, pp. 23-24.
- ↑ R. Ebermann, Ibrahim Elmadfa: Textbook food chemistry and nutrition . Springer Verlag, 2008, p. 131.
- ↑ a b c d C. Ekmekcioglu, W. Marktl: Essential trace elements: Clinic and nutritional medicine. Ed .: W. Marktl. Springer Verlag, 2006, p. 179 ff.
- ^ CA Stegeman, JR Davis: Dentistry and Nutrition: Basics - Counseling - Prevention. Elsevier, Urban & Fischer Verlag, 2006, p. 244.
- ↑ a b ARD-Magazin Plusminus and NDR Info: Beauty product silica under suspicion , from November 6, 2007.
- ↑ Instructions for use Abbey silica powder for skin, hair and nails . As of June 2009.
- ↑ see also English Wikipedia