Grein þessi er eftir Dr. Henk Hendriks sem fjallar um kísil sem næringarefni og mikilvægi hans fyrir líkaman. Greinin er á ensku fyrir þá sem hafa áhuga á því að lesa hana hér að neðan:
Dr. Henk Hendriks
Silica is a mineral which is highly abundant in nature. Silica consists of one atom of silicon bound to two atoms of oxygen, chemically named silicon dioxide (SiO2). Silicon is neither a metal nor a non-metal; it is a metalloid. This means that it has properties of both a metal and a non-metal. The human body uses silicon and has health benefits [1]. Scientists believe silicon is involved in several important processes in the body and consider it an essential nutrient [2,3].
The common mineral silica is usually found as quartz, an abundant ingredient in sand. Silica is mainly present as a solid, because it poorly dissolves in water. Silica exists as molecules, but mainly as particles of various sizes and in various forms. Some of these particles may be detrimental to health. Specifically when silica particles are inhaled on a regular basis and when inhaled silica particles are large, these may become deleterious in the long-term [4].
Conversely, silica molecules and silica particles consumed through the mouth are beneficial. Silica consists of 47% silicon and is a natural constituent of our diet. Dietary silicon consumption mainly occurs as silica dissolved in water and as monosilicic acid present in food stuffs. Silica consumption is accepted as being safe by both European [5] and United States authorities [6].
However, the human body gets little silicon from the diet, because our diet contains low quantities of it and because it is poorly absorbed in the intestines. Whereas some foods contain relatively high concentrations of silicon such as some cereals, some fruits and vegetables and some beverages [7], absorption of silicon from it is generally low [8]. Bodily uptake from the diet (in another term: bioavailability) varies. It seems that the higher the concentration of silicon in a food the lower its bioavailability. Beverages in general appear to have a high bioavailability of silicon. Silica containing waters have also been shown to increase the uptake of silicon, because it increased urinary silicon excretion [9]. In other words: silicon dissolved in beverages is best taken up by the body [10-12].
Silicon deficiency has not been described for humans, but animals which were made silicon deficient have deformities in skull and bones, poorly formed joints, reduced cartilage, and a disturbed mineral balance in bones [3,13]. This shows that silicon is an important dietary factor in bone health. Therefore, scientists propose that healthy diets should include foods that provide trace elements like silicon in amounts that promote health even if currently not considered essential. A dietary intake of silica of 25 mg/day corresponding to ~10 mg/day of silicon, would be an adequate intake without adverse effects [14].
Silicon appears to be important for bone health. Various population studies have supported such a role [15-18]. Supplementation with silicon increased bone volume and bone mineral density in people with osteoporosis [17,19]. Also, studies in cells have shown that silicon stimulates processes important for healthy bones [20,21]. Animal studies show that supplementation with silicon improves bone health of mice and rats [22-25]. It is not clear how silicon affects bone health. Scientists suggest that silicon supports the production of a protein important for the structure of bones and skin: collagen [26]. Others suggest that silicon may support the stabilization of collagens or similar structural molecules [27].
Bone implants (e.g. dental implants, surgical bone replacements) combined with silicon and silica stimulated new bone growth by increasing collagen production [28,29]. Various forms of silicon are currently being investigated for their possible application as a new fracture healing biomaterial [30,31]. Also, very small particles of silica are being studied for their antimicrobial effects [32-34]. Silicon may not only improve bone health by stimulating collagen synthesis. An optimized collagen synthesis by silicon may also improve the structural integrity of skin [35,36], contribute to healthier hair [37] and nails [38,39] and support wound healing [40].
Some studies suggest that silica in drinking water and other forms of silicon in beverages may counteract the detrimental effects of aluminium in the diet and may therefore help in the prevention of Alzheimer’s disease [10,41,42].
Although the specific biochemical or physiological roles of silicon in the human body are largely unknown, these functions are generally considered to exist. As a result, there is growing interest in the potential therapeutic effects of water-soluble silica on human health. GeoSilica Iceland products combine silica with other minerals depending on your preference to stimulate various functions. Silica in all GeoSilica Iceland products provides your daily portion of silicon.
Literature
[1] Martin, K. R. Silicon: the health benefits of a metalloid. Metal ions in life sciences 13, 451-473, doi:10.1007/978-94-007-7500-8_14 (2013).
[2] Price, C. T., Langford, J. R. & Liporace, F. A. Essential Nutrients for Bone Health and a Review of their Availability in the Average North American Diet. The open orthopaedics journal 6, 143-149, doi:10.2174/1874325001206010143 (2012).
[3] Carlisle, E. M. Silicon: an essential element for the chick. Science (New York, N.Y.) 178, 619-621, doi:10.1126/science.178.4061.619 (1972).
[4] Steenland, K. & Ward, E. Silica: a lung carcinogen. CA: a cancer journal for clinicians 64, 63-69, doi:10.3322/caac.21214 (2014).
[5] EFSA. Re-evaluation of silicon dioxide (E 551) as a food additive. EFSA Journal 16, doi:doi: 10.2903/j.efsa.2018.5088 (2018).
[6] FDA. Sec.172.480 Silicon dioxide. (2019).
[7] Pennington, J. A. Silicon in foods and diets. Food additives and contaminants 8, 97-118, doi:10.1080/02652039109373959 (1991).
[8] Robberecht, H., Van Cauwenbergh, R., Van Vlaslaer, V. & Hermans, N. Dietary silicon intake in Belgium: Sources, availability from foods, and human serum levels. The Science of the total environment 407, 4777-4782, doi:10.1016/j.scitotenv.2009.05.019 (2009).
[9] Li, Z. et al. Absorption of silicon from artesian aquifer water and its impact on bone health in postmenopausal women: a 12 week pilot study. Nutr J 9, 44, doi:10.1186/1475-2891-9-44 (2010).
[10] Gonzalez-Munoz, M. J. et al. Silicic Acid and Beer Consumption Reverses the Metal Imbalance and the Prooxidant Status Induced by Aluminum Nitrate in Mouse Brain. Journal of Alzheimer's disease : JAD 56, 917-927, doi:10.3233/jad-160972 (2017).
[11] Sanchez-Muniz, F. J. et al. The Nutritional Components of Beer and Its Relationship with Neurodegeneration and Alzheimer's Disease. Nutrients 11, doi:10.3390/nu11071558 (2019).
[12] Sripanyakorn, S. et al. The comparative absorption of silicon from different foods and food supplements. The British journal of nutrition 102, 825-834, doi:10.1017/s0007114509311757 (2009).
[13] Schwarz, K. & Milne, D. B. Growth-promoting effects of silicon in rats. Nature 239, 333-334, doi:10.1038/239333a0 (1972).
[14] Martin, K. R. Dietary Silicon: Is Biofortification Essential? Journal of Nutrition and Food Science Forecast 1, 1006 (2018).
[15] Jugdaohsingh, R. et al. Dietary silicon intake is positively associated with bone mineral density in men and premenopausal women of the Framingham Offspring cohort. Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research 19, 297-307, doi:10.1359/jbmr.0301225 (2004).
[16] Macdonald, H. M. et al. Dietary silicon interacts with oestrogen to influence bone health: evidence from the Aberdeen Prospective Osteoporosis Screening Study. Bone 50, 681-687, doi:10.1016/j.bone.2011.11.020 (2012).
[17] Eisinger, J. & Clairet, D. Effects of silicon, fluoride, etidronate and magnesium on bone mineral density: a retrospective study. Magnesium research 6, 247-249 (1993).
[18] Choi, M. K. & Kim, M. H. Dietary Silicon Intake of Korean Young Adult Males and Its Relation to their Bone Status. Biol Trace Elem Res 176, 89-104, doi:10.1007/s12011-016-0817-x (2017).
[19] Schiano, A. et al. [Silicon, bone tissue and immunity]. Revue du rhumatisme et des maladies osteo-articulaires 46, 483-486 (1979).
[20] Keeting, P. E. et al. Zeolite A increases proliferation, differentiation, and transforming growth factor beta production in normal adult human osteoblast-like cells in vitro. Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research 7, 1281-1289, doi:10.1002/jbmr.5650071107 (1992).
[21] Reffitt, D. M. et al. Orthosilicic acid stimulates collagen type 1 synthesis and osteoblastic differentiation in human osteoblast-like cells in vitro. Bone 32, 127-135, doi:10.1016/s8756-3282(02)00950-x (2003).
[22] Maehira, F., Miyagi, I. & Eguchi, Y. Effects of calcium sources and soluble silicate on bone metabolism and the related gene expression in mice. Nutrition (Burbank, Los Angeles County, Calif.) 25, 581-589, doi:10.1016/j.nut.2008.10.023 (2009).
[23] Jugdaohsingh, R., Watson, A. I., Bhattacharya, P., van Lenthe, G. H. & Powell, J. J. Positive association between serum silicon levels and bone mineral density in female rats following oral silicon supplementation with monomethylsilanetriol. Osteoporosis international : a journal established as result of cooperation between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA 26, 1405-1415, doi:10.1007/s00198-014-3016-7 (2015).
[24] Hott, M., de Pollak, C., Modrowski, D. & Marie, P. J. Short-term effects of organic silicon on trabecular bone in mature ovariectomized rats. Calcified tissue international 53, 174-179, doi:10.1007/bf01321834 (1993).
[25] Rico, H. et al. Effect of silicon supplement on osteopenia induced by ovariectomy in rats. Calcified tissue international 66, 53-55, doi:10.1007/s002230050010 (2000).
[26] Kivirikko, K. I. & Myllyla, R. Post-translational processing of procollagens. Annals of the New York Academy of Sciences 460, 187-201, doi:10.1111/j.1749-6632.1985.tb51167.x (1985).
[27] Schwarz, K. A bound form of silicon in glycosaminoglycans and polyuronides. Proceedings of the National Academy of Sciences of the United States of America 70, 1608-1612, doi:10.1073/pnas.70.5.1608 (1973).
[28] Fielding, G. & Bose, S. SiO2 and ZnO dopants in three-dimensionally printed tricalcium phosphate bone tissue engineering scaffolds enhance osteogenesis and angiogenesis in vivo. Acta biomaterialia 9, 9137-9148, doi:10.1016/j.actbio.2013.07.009 (2013).
[29] Fielding, G. A., Sarkar, N., Vahabzadeh, S. & Bose, S. Regulation of Osteogenic Markers at Late Stage of Osteoblast Differentiation in Silicon and Zinc Doped Porous TCP. Journal of functional biomaterials 10, doi:10.3390/jfb10040048 (2019).
[30] Ilyas, A. et al. Amorphous Silica: A New Antioxidant Role for Rapid Critical-Sized Bone Defect Healing. Advanced healthcare materials 5, 2199-2213, doi:10.1002/adhm.201600203 (2016).
[31] Jiao, K. et al. Biphasic silica/apatite co-mineralized collagen scaffolds stimulate osteogenesis and inhibit RANKL-mediated osteoclastogenesis. Acta biomaterialia 19, 23-32, doi:10.1016/j.actbio.2015.03.012 (2015).
[32] Shevchenko, S. N. et al. Antimicrobial Effect of Biocompatible Silicon Nanoparticles Activated Using Therapeutic Ultrasound. Langmuir : the ACS journal of surfaces and colloids 33, 2603-2609, doi:10.1021/acs.langmuir.6b04303 (2017).
[33] Croissant, J. G., Fatieiev, Y., Almalik, A. & Khashab, N. M. Mesoporous Silica and Organosilica Nanoparticles: Physical Chemistry, Biosafety, Delivery Strategies, and Biomedical Applications. Advanced healthcare materials 7, doi:10.1002/adhm.201700831 (2018).
[34] Drago, L., Toscano, M. & Bottagisio, M. Recent Evidence on Bioactive Glass Antimicrobial and Antibiofilm Activity: A Mini-Review. Materials (Basel, Switzerland) 11, doi:10.3390/ma11020326 (2018).
[35] Araujo, L. A., Addor, F. & Campos, P. M. Use of silicon for skin and hair care: an approach of chemical forms available and efficacy. Anais brasileiros de dermatologia 91, 331-335, doi:10.1590/abd1806-4841.20163986 (2016).
[36] Herreros, F. O., Cintra, M. L., Adam, R. L., de Moraes, A. M. & Metze, K. Remodeling of the human dermis after application of salicylate silanol. Archives of dermatological research 299, 41-45, doi:10.1007/s00403-007-0739-8 (2007).
[37] Wickett, R. R. et al. Effect of oral intake of choline-stabilized orthosilicic acid on hair tensile strength and morphology in women with fine hair. Archives of dermatological research 299, 499-505, doi:10.1007/s00403-007-0796-z (2007).
[38] Barel, A. et al. Effect of oral intake of choline-stabilized orthosilicic acid on skin, nails and hair in women with photodamaged skin. Archives of dermatological research 297, 147-153, doi:10.1007/s00403-005-0584-6 (2005).
[39] Lassus, A. Colloidal silicic acid for oral and topical treatment of aged skin, fragile hair and brittle nails in females. J Int Med Res 21, 209-215, doi:10.1177/030006059302100406 (1993).
[40] Quignard, S., Coradin, T., Powell, J. J. & Jugdaohsingh, R. Silica nanoparticles as sources of silicic acid favoring wound healing in vitro. Colloids and surfaces. B, Biointerfaces 155, 530-537, doi:10.1016/j.colsurfb.2017.04.049 (2017).
[41] Rondeau, V., Jacqmin-Gadda, H., Commenges, D., Helmer, C. & Dartigues, J. F. Aluminum and silica in drinking water and the risk of Alzheimer's disease or cognitive decline: findings from 15-year follow-up of the PAQUID cohort. American journal of epidemiology 169, 489-496, doi:10.1093/aje/kwn348 (2009).
[42] Glick, J. L. & McMillan, P. A. A multipronged, nutritional-based strategy for managing Alzheimer's disease. Medical hypotheses 91, 98-102, doi:10.1016/j.mehy.2016.04.007 (2016).