Silicon — Aluminum Interactions and Biology
J. D. Birchall
Department of Chemistry, Keele University, Keele, Staffordshire, ST5 5BG, United Kingdom
The Colloid Chemistry of Silica
Chapter 31, pp 601–615
Chapter DOI: 10.1021/ba-1994-0234.ch031
Advances in Chemistry, Vol. 234
ISBN13: 9780841221031eISBN: 9780841224162
Publication Date (Print): July 22, 2009
Copyright © 1994 American Chemical Society
ABSTRACT
Silicon is listed as an essential element. Its removal from the diet of experimental animals has been shown to result in reduced growth rate (reversed on silicon supplementation) and changes to bone formation and the synthesis of collagenous connective tissue. However, in spite of much effort, no organic binding (e.g., to proteins) of silicon has been convincingly demonstrated under physiological conditions in which silicon exists as silicic acid, Si (OH)4, and no biochemical rationale has been proposed to account for the effects of silicon deficiency. However, recent research indicates that a major role for silicon (as silicic acid) is to reduce the bioavailability of aluminum, which is toxic when it gains entry into biological systems, but which is normally largely excluded. The formation of subcolloidal hydroxyaluminosilicate species is shown to prevent the absorption of aluminum in fish via gill epithelia. The generality of this effect is discussed. The symptoms of silicon deficiency in experimental animals seem likely to result from aluminum toxicity, so that the environmental balance for the two elements may be critical. This chapter reviews the present position.
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