Choline-stabilised orthosilicic acid added for nutritional purposes to food supplements

Orthosilicic acid [Si(OH)4] is the major silicon species present in drinking water and other liquids, including beer, and is the most readily available source of silicon to man. The essentiality of silicon for man has not been established and a functional role for silicon in man has not yet been identified. The bioavailability of silicon under the form of orthosilicic acid has been proven for cholinestabilised orthosilicic acid. Acute oral toxicity studies in male and female rats as well as mice have been performed. The calculated mean LD50 value for ch-OSA exceeds (for both animal species) 5000 mg/kg bw. Concerning the acute oral toxicology of choline, an LD50 value of 6640 mg/kg bw as choline chloride was found. Subchronic toxicity studies on ch-OSA were conducted both in animals (rodents and mammals) and humans (supplementation studies). No adverse effects were observed. The proposed dosage of ch-OSA in food supplements is 5 to 10 mg silicon/day (equivalent to 0.083-0.17 mg silicon/kg bw/day for a 60 kg person). The equivalent intake of choline amounts to 101-203 mg choline/day for the ch-OSA liquid, and to 117-234 mg choline/day for the ch-OSA pellets. This results in an intake of 135-272 mg choline chloride/day for ch-OSA liquid and of 157-314 mg choline chloride/day for ch-OSA pellets. The European Food Safety Authority estimated the typical dietary intake of silicon to be 20-50 mg/day, corresponding to 0.3-0.8 mg silicon/kg bw/day for a 60 kg person, and concluded that these intakes are unlikely to cause adverse effects. The Panel concludes that silicon is bioavailable from choline-stabilised orthosilicic acid and that its use in supplements, at the proposed use levels of the source, is of no safety concern provided that the upper level for choline is not exceeded.