Jugdaohsingh R, Reffitt D M, Oldham C, Day J P, Fifield L K, Thompson R P, Powell J J
Gastrointestinal Laboratory, The Rayne Institute, St Thomas' Hospital, London, UK.
Am J Clin Nutr. 2000 Apr;71(4):944-9. doi: 10.1093/ajcn/71.4.944.
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.
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).
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.
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.
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.
可溶性硅是饮食中普遍存在的成分，可能是膳食铝的天然配体，并且可能防止其在动物体内的积累和毒性作用。然而，先前关于可溶性硅对铝吸收和毒性抑制作用的研究结果相互矛盾。我们最近鉴定出一种可溶性硅聚合物，即低聚硅，它对铝的亲和力比单体硅高得多，并且可能参与铝的螯合作用。
通过使用铝 - 26作为示踪剂，我们研究了低聚硅和单体硅对铝生物利用度的影响（研究1），并比较了低聚硅和单体硅在人体胃肠道中硅的可利用性（研究2）。
在研究1中，三名健康志愿者分别单独摄入铝（对照）、铝与低聚硅（17毫克）以及铝与单体硅（17毫克）。在研究2中，五名健康志愿者摄入了低聚硅和单体硅两种形式（34毫克）。对血清和尿液样本进行铝和硅的分析。
与对照组相比，低聚硅使铝的可利用性降低了67%（P = 0.01），而单体硅没有影响（P = 0.40）。单体硅很容易从胃肠道吸收，然后通过尿液排出（53%），而低聚硅未被检测到吸收或排出。
可溶性硅的低聚、高铝亲和力形式降低了人体胃肠道中铝的可利用性。其在改善其他生物系统中铝毒性方面的潜在作用值得关注。
