The silicon supplement 'Monomethylsilanetriol' is safe and increases the body pool of silicon in healthy Pre-menopausal women

Background: Monomethylsilanetriol (MMST) has been used for decades as an oral silicon supplement for bone and connective tissue health, although there are no formal data on its in vivo utilisation or safety following sustained dosing. Methods: To investigate whether MMST contributes to the body pool of silicon and, secondly, to establish its safety following 4 weeks' supplementation in humans, twenty-two healthy pre-menopausal women (22-38 years) were recruited and supplemented with MMST at the maximum daily recommended dose (10.5 mg Si/day) for 4 weeks in a double-blind, randomised, placebo-controlled, cross-over design (i.e. 8 weeks in total). Fasting serum and urine samples were collected at baseline and at the end of the 4-week supplementation/placebo periods for analysis of total silicon by inductively coupled plasma optical emission spectrometry, MMST by proton nuclear magnetic resonance spectroscopy and full serum biochemistry. Participants also reported on, by questionnaire, their health, well-being and quality of life at 0, 4 and 8 weeks. Results: Overall, 4-weeks supplementation with MMST significantly increased total fasting Si concentrations in serum and urine (P <= 0.003; paired t-test). MMST was semi-quantifiable in serum and quantifiable in urine, but only accounted for ca. 50% and 10%, respectively, of the increased total-Si concentration. There were no reported adverse effects (i.e. changes to health and well-being) or serum biochemical changes with MMST versus placebo. Conclusions: Our data indicate that oral MMST is safe, is absorbed and undergoes sufficient metabolism in vivo to raise fasting serum silicon levels, consistent with other well absorbed forms of dietary silicon (e. g. orthosilicic acid). It thus appears to be a suitable silicon supplement.