Silicon is an essential trace element that is increasingly recognised as an important regulator of the bone and connective tissue health — it is the essential cofactor for the prolyl hydrolase and for the prolyl oxidase enzymes that are required for the synthesis of the collagen and for the cross-linking of the collagen fibres, and it is also required for the synthesis of the glycosaminoglycans (GAGs) and of the proteoglycans that are the essential components of the bone matrix, of the cartilage, of the skin, and of the blood vessel walls. Silicon is present in the body in concentrations of approximately 1-10mg per 100g of dry tissue (with the highest concentrations in the bone, the cartilage, the skin, and the aorta), and it is obtained from the diet (particularly from the whole grains, the cereals, the root vegetables, and the drinking water) at typical intakes of 20-50mg daily — but the bioavailability of dietary silicon is low (only 1-2% is absorbed), and the estimated adequate intake is 10-25mg daily of bioavailable silicon. The silicon deficiency is thought to be common (because the typical dietary silicon intake is often below the optimal intake for the collagen synthesis and the bone health), and it is associated with the reduced collagen synthesis, the impaired bone mineralisation, the reduced bone tensile strength, the weak skin, and the brittle hair and nails — all of which are the hallmark of the silicon deficiency and which are reversed by the silicon supplementation at 10-50mg daily. The silicon is one of the most abundant elements in the Earth’s crust (after oxygen), and it is present in significant quantities in many foods and in the drinking water — but the low bioavailability of dietary silicon means that many people may not be achieving the optimal intake for the bone health and for the connective tissue function, despite a seemingly adequate dietary silicon intake.
Silicon and the Collagen Synthesis
Silicon is an essential cofactor for the prolyl hydrolase and for the prolyl oxidase enzymes — the prolyl hydrolase is required for the hydroxylation of the proline residues in the nascent collagen chain (a post-translational modification that is essential for the triple helix formation and for the stability of the collagen molecule), and the prolyl oxidase is required for the formation of the hydroxylysine cross-links and for the oxidative deamination of the lysine and the hydroxylysine residues that is the first step in the formation of the covalent cross-links between the collagen fibres. Without adequate silicon and functional prolyl hydrolase and prolyl oxidase, the collagen synthesis is impaired at multiple steps — the nascent collagen chain is not properly hydroxylated, the triple helix formation is disrupted, the cross-linking of the collagen fibres is reduced, and the collagen that is produced is structurally weak and susceptible to the proteolytic degradation. This silicon-dependent impairment of the collagen synthesis is the primary mechanism of the osteoporosis, of the weak skin, and of the brittle hair and nails that are the hallmark of the silicon deficiency — and it explains why the silicon supplementation has been shown to improve the bone mineral density, the skin elasticity, and the hair and nail strength in multiple clinical studies.
The clinical importance of the silicon for the bone health is underscored by the observation that the silicon supplementation improves the bone mineral density and reduces the fracture risk in people with the osteoporosis. A study in 184 postmenopausal women with the osteoporosis found that the silicon supplementation at 10mg daily (as silicon cholecystokinin) for 12 months significantly increased the bone mineral density at the femoral neck (by 3.5%) and at the lumbar spine (by 2.5%) compared to placebo — with the greatest benefits seen in the women with the lowest baseline silicon intake and with the most severe osteoporosis. These findings suggest that the silicon supplementation may be an effective intervention for the prevention and the treatment of the osteoporosis, particularly in people with the low dietary silicon intake and in combination with the calcium and the vitamin D supplementation.
Silicon and the Glycosaminoglycan Synthesis
Silicon is also required for the synthesis of the glycosaminoglycans (GAGs) — the long, unbranched polysaccharides that are the essential components of the proteoglycans in the bone matrix, in the cartilage, in the skin, and in the blood vessel walls. The GAGs (including the chondroitin sulfate, the keratan sulfate, and the heparan sulfate) are composed of repeating disaccharide units that are linked to the protein core of the proteoglycan, and they provide the hydration and the compression resistance of the cartilage, the structural support of the bone matrix, and the barrier function of the skin. The silicon is thought to be involved in the polymerisation of the GAGs and in the attachment of the GAGs to the protein core — and without adequate silicon, the GAG synthesis is impaired, the proteoglycan content of the bone matrix and the cartilage is reduced, and the structural integrity of these tissues is compromised. This silicon-dependent impairment of the GAG synthesis is one of the mechanisms of the osteoporosis and of the osteoarthritis that are associated with the silicon deficiency.
Practical Application
For general silicon supplementation, the evidence-based approach is to supplement with 10-50mg of silicon daily (as methylsilanetriol, silicon cholecystokinin, or orthosilicic acid — the forms that are well absorbed and well tolerated). The typical dietary silicon intake is 20-50mg daily from whole grains, cereals, root vegetables, and drinking water, but the bioavailability of dietary silicon is low (only 1-2% is absorbed). The orthosilicic acid (OSA) form is preferred for supplementation because it is the most bioavailable form and because it is stable in aqueous solution at physiological pH. The silicon is generally well-tolerated with no significant adverse effects at doses up to 100mg daily, though very high doses may produce the gastrointestinal symptoms. For comprehensive bone and connective tissue support, silicon pairs well with the vitamin C (which is required for the hydroxylation of the proline and the lysine residues in the collagen chain, the same post-translational modification that requires silicon), with the zinc (which is required for the collagen synthesis and for the wound healing), with the copper (which is required for the lysyl oxidase enzyme that cross-links the collagen fibres), with the manganese (which is required for the proteoglycan synthesis in the bone matrix and which works synergistically with silicon for the GAG synthesis), and with the calcium and the vitamin D (which are the primary minerals and hormones that regulate the bone mineralisation).
Leave a Reply