描述
Silicon (Si) is the second most abundant element in the Earth's crust and although there has been interest in the biological role of Si since the beginning of the century, it is only in the last three decades that it has been suggested as an essential trace element. Si may have a role in a number of areas of human physiology and metabolism, especially bone and connective tissue formation, but possibly also gene expression and cardiovascular health. Si is rarely found in its elemental form as it readily reacts with atmospheric O2 and water to produce silicates. Physiologically, it exists as an ion in the body.