경희대학교 동서의학대학원 의 학 영 양 학 과 김 선 아

Ⅲ. Collagen and Silicon
Silicon (Si) is a ubiquitous environmental element found mainly as insoluble
silicates, although small amounts of soluble Si are also present in natural
waters, chiefly as orthosilicic acid [Si(OH)4].(Farmer VC. 1986) Around
neutral pH, orthosilicic acid polymerises at concentrations much above 2
mM, forming a range of silica species from soluble dimers to colloids and
solid phase silica (Iler RK..1979) Some plants and lower animals may
promote this reaction, as they use polymeric silica for structure and
growth.(Cha JN, Shimizu K, Zhou Y, Christiansen SC, Chmelka BF, Stucky
GD, Morse DE. 1999; Kröger N, Deutzmann R, Sumper M. 1999; Sangster
AG, Hodson MJ. 1986) The normal diet contains orthosilicic acid present in
water or following hydrolysis of foods in the gastrointestinal tract,
nonhydrolyzed polymeric silica from plants (Pennington JA. 1991), and
silicates due mainly to soil and dust contamination or as food additives
(Hansen M, Marsden J. 1987; Villota R, Hawkes JG. 1986). Absorption
studies have shown that only orthosilicic acid is in a bioavailable form with
uptake in humans exceeding 50% of the ingested dose (Jugdaohsingh R,
Reffitt DM, Oldham C, Day JP, Fifield K, Thompson RPH, et al. 2000; Reffitt
DM, Jugdaohsingh R, Thompson RPH, Powell JJ. 1999). Fasting
concentrations of Si in plasma are 2-10 M, rising to 20-30 M after meals,
and approximately 700 mol/day is normally excreted in urine.
In 1972, Carlisle (Carlisle EM. 1972) and Schwarz and Milne (Schwarz K,
Milne DB. 1972) first reported that silicon deficiency in chicks and rats led
to abnormally shaped bones and defective cartilagenous tissue, both of
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