Martin K R
POM Wonderful LLC, Los Angeles, CA 91326, USA.
J Nutr Health Aging. 2007 Mar-Apr;11(2):94-7.
There is considerable interest in the effects of silica on human health in contrast to prior research which focused solely on the toxic effects of inhaled crystalline silica. However, multiple forms of silica exist in nature and silicon, a component, is the second most prevalent element after oxygen. Silica has widespread industrial applications including use as a food additive, i.e., anti-caking agent, as a means to clarify beverages, control viscosity, as an anti-foaming agent, dough modifier, and as an excipient in drugs and vitamins. Chemically, silica is an oxide of silicon, viz., silicon dioxide, and is generally colorless to white and insoluble in water. When associated with metals or minerals the family of silicates is formed. There are several water soluble forms of silica referred collectively to as silicic acid (ortho, meta, di, and tri-silicates), which are present in surface and well water in the range of 1--100 mg/L. Orthosilicic acid is the form predominantly absorbed by humans and is found in numerous tissues including bone, tendons, aorta, liver and kidney. Compelling data suggest that silica is essential for health although no RDI has been established. However, deficiency induces deformities in skull and peripheral bones, poorly formed joints, reduced contents of cartilage, collagen, and disruption of mineral balance in the femur and vertebrae. Very little toxicity data exist regarding aqueous silica consumption due, in part, to the lack of anecdotal reports of toxicity and general presumption of safety. However, a few rodent studies have been conducted, which indicate a No Observed Adverse Effects Level (NOAEL) of 50,000 ppm (mg/L) for dietary silica. In conclusion, many forms of silica exist in nature and compelling data support myriad beneficial effects of silica in water.
与之前仅关注吸入结晶二氧化硅毒性作用的研究不同，目前人们对二氧化硅对人体健康的影响有着浓厚兴趣。然而，自然界中存在多种形式的二氧化硅，其组成成分硅是仅次于氧的第二大普遍元素。二氧化硅在工业上有广泛应用，包括用作食品添加剂，即抗结剂，用于澄清饮料、控制粘度、作为消泡剂、面团改良剂，以及作为药物和维生素的辅料。从化学角度看，二氧化硅是硅的氧化物，即二氧化硅，通常无色至白色，不溶于水。当与金属或矿物质结合时，会形成硅酸盐家族。有几种水溶性二氧化硅形式统称为硅酸（原硅酸、偏硅酸、二硅酸和三硅酸），它们在地表水和井水中的含量范围为1-100毫克/升。原硅酸是人体主要吸收的形式，存在于包括骨骼、肌腱、主动脉、肝脏和肾脏在内的众多组织中。有力的数据表明二氧化硅对健康至关重要，尽管尚未确定推荐膳食摄入量（RDI）。然而，缺乏二氧化硅会导致颅骨和外周骨畸形、关节发育不良、软骨和胶原蛋白含量降低，以及股骨和椎骨矿物质平衡紊乱。关于摄入含水二氧化硅的毒性数据非常少，部分原因是缺乏毒性的轶事报道以及普遍认为其安全。然而，已经进行了一些啮齿动物研究，结果表明膳食二氧化硅的无观察到有害作用水平（NOAEL）为50,000 ppm（毫克/升）。总之，自然界中存在多种形式的二氧化硅，有力的数据支持了水中二氧化硅的多种有益作用。
