Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Comparative Study
. 2000 Apr;71(4):944-9.
doi: 10.1093/ajcn/71.4.944.

Oligomeric but Not Monomeric Silica Prevents Aluminum Absorption in Humans

Affiliations
Comparative Study

Oligomeric but Not Monomeric Silica Prevents Aluminum Absorption in Humans

R Jugdaohsingh et al. Am J Clin Nutr. .

Abstract

Background: Soluble silica, a ubiquitous component of the diet, may be the natural ligand for dietary aluminum and may prevent its accumulation and toxicity in animals. However, previous studies on the inhibition of aluminum absorption and toxicity by soluble silica have produced conflicting results. We recently identified a soluble silica polymer, oligomeric silica, that has a much higher affinity for aluminum than does monomeric silica and that may be involved in the sequestration of aluminum.

Objective: By using (26)Al as a tracer, we investigated the effects of oligomeric and monomeric silica on the bioavailability of aluminum (study 1) and compared the availability of silicon from oligomeric and monomeric silica in the human gastrointestinal tract (study 2).

Design: In study 1, three healthy volunteers each ingested aluminum alone (control), aluminum with oligomeric silica (17 mg), and aluminum with monomeric silica (17 mg). In study 2, five healthy volunteers ingested both the oligomeric and monomeric forms of silica (34 mg). Serum and urine samples were analyzed for aluminum and silicon.

Results: Oligomeric silica reduced the availability of aluminum by 67% (P = 0.01) compared with the control, whereas monomeric silica had no effect (P = 0.40). Monomeric silica was readily taken up from the gastrointestinal tract and then excreted in urine (53%), whereas oligomeric silica was not detectably absorbed or excreted.

Conclusions: The oligomeric, high-aluminum-affinity form of soluble silica reduces aluminum availability from the human gastrointestinal tract. Its potential role in the amelioration of aluminum toxicity in other biological systems requires attention.

Similar articles

See all similar articles

Cited by 20 articles

See all "Cited by" articles

Publication types

LinkOut - more resources

Feedback