ISMNT News #56. According to a recent hypothesis, aluminium plays a role in the development of Alzheimers Disease. Serum aluminium was also found increased up to 2-3-fold in patients with dementia including Alzheimers Disease (J Inorg Biochem 1998;69:171-176). The aluminium absorption from normal diet was enhanced. The question arises therefore whether aluminium uptake can be reduced by dietary interventions. One such approach could involve silicon which reduced aluminium uptake in rats. Silicon, in its various forms (silicic acid through to hydrated amorphous silica) is important in various biological processes (J Inorg Biochem 1998;69:181-191). Clearly further work is needed to assess whether silicon can reduce aluminium uptake when it is enhanced.

The key reference is by:

Belles M, Sanchez DJ, Gomez M, Corbella J, Domingo JL

Laboratory of Toxicology and Environmental Health, School of Medicine, Rovira i Virgili University, Reus, Spain

Silicon reduces aluminum accumulation in rats: relevance to the aluminum hypothesis of Alzheimer disease

Alzheimer Dis Assoc Disord 1998 Jun;12(2):83-87

In recent years, a possible relation between the aluminum and silicon levels in drinking water and the risk of Alzheimer disease (AD) has been established. It has been suggested that silicon may have a protective effect in limiting oral aluminum absorption.

The present study was undertaken to examine the influence of supplementing silicon in the diet to prevent tissue aluminum retention in rats exposed to oral aluminum. Three groups of adult male rats were given by gavage 450 mg/kg/day of aluminum nitrate nonahydrate 5 days a week for 5 weeks. Concurrently, animals received silicon in the drinking water at 0 (positive control), 59, and 118 mg Si/L. A fourth group (-Al, - Si) was designated as a negative control group. At the end of the period of aluminum and silicon administration, urines were collected for 4 consecutive days, and the urinary aluminum levels were determined. The aluminum concentrations in the brain (various regions), liver, bone, spleen, and kidney were also measured. For all tissues, aluminum levels were significantly lower in the groups exposed to 59 and 118 mg Si/L than in the positive control group; significant reductions in the urinary aluminum levels of the same groups were also found.

The current results corroborate that silicon effectively prevents gastrointestinal aluminum absorption, which may be of concern in protecting against the neurotoxic effects of aluminum.