Life Extension Magazine

Life Extension Magazine April 2003


Silicon: An Overlooked
Trace Mineral


Bioavailability and efficacy of silicon supplements

When selecting a silicon supplement, the most important considerations should be safety and bioavailability. (Bioavailability is a complex term for the degree of absorption and the biological response to the silicon compounds which are present in the product.) Organic silicon compounds, which are laboratory synthesized, contain silicon-carbon bonds. These molecules are normally not present in biological systems and can be very toxic. For this reason it is safest to use silicon compounds that are already present in nature or compounds that are the derivatives of natural products. Common silicon supplements include:

Plant extracts:

Bamboo and algae usually have high silica concentrations. However, plant extracts are often not standardized and the silicon concentration in these products varies greatly. As the silicon from plant extracts cannot be absorbed directly through the stomach wall, the bioavailability of these products requires high stomach acidity in order to produce soluble orthosilicic acid.

Colloidal silicon gel:

These products offer large, insoluble, polymer molecules of silicic acid suspended in water. Like plant extracts, these polymer-molecules cannot be absorbed directly through the stomach wall and therefore have a low rate of absorption. The stomach's ability to produce soluble orthosilicic acid is also limited to low concentration levels due to orthosilicic acid's limited stability.

Stabilized orthosilicic acid:

Now on the market is a liquid, stabilized orthosilicic acid concentrate. A research group from the University of Antwerp in Belgium has published a supplementation study describing a high rate of silicon absorption from a liquid silicon supplement containing 2% silicon in the form of stabilized orthosilicic acid. In the six-month study with calves, the total dietary silicon intake was increased by only 5% in the form of stabilized orthosilicic acid. Even with such a small dose of orthosilicic acid, the supplemented group showed 70% higher blood silicon levels than the unsupplemented group. These higher silicon blood levels also translated into a 12% higher collagen concentration in the skin of supplemented animals compared to unsupplemented animals. This study clearly demonstrated that the bioavailability of stabilized orthosilicic acid concentrate is very high compared to dietary silicon.19


The slow and lengthy process of soil erosion breaks down rocks into clay and loam; eventually the silicates react with water to form soluble silicon molecules. These soluble silicon molecules are called orthosilicic acid or monomeric silicic acid. Orthosilicic acid is the natural water soluble compound present in sea water, drinking water and other beverages such as beer. However, natural mineral water has extremely low concentration levels of orthosilicic acid (0.1-1.0 parts per million) due to the molecule's limited stability. Attempts to increase the concentration of orthosilicic acid in mineral water result in the linking of several small orthosilicic acid molecules into larger, insoluble polymer-molecules. This so-called polymerization of orthosilicic acid occurs also in plants where the silicon fibers are important for the mechanical strength and flexibility of the plant. Silicon accumulating plants such as bamboo are characterized by a strong but flexible structure, whereas silicon deficiency in soil and plant tissues results in weakened mechanical strength.


Two independent Belgian research groups demonstrated both in a comparative human study that the total silicon absorption by the human body is considerably higher (more than 2.5 times higher) after supplementation of stabilized orthosilicic acid (as present in a product called BioSilTM) compared to plant extracts or colloidal supplements. In fact, only BioSilTM supplementation resulted in a statistical significant increase in silicon absorption compared to the placebo. Without exception, each test subject had a similar absorption from orthosilicic acid, whereas large differences among subjects were found for the other silicon supplements.20,21

The bone stimulatory properties of silicon was recently investigated in an extended study on chicks. For the first time a normal diet was used instead of silicon deficient diet, which made it possible to observe the superior biological action of silicon in supplemented chicks compared to a control group. The silicon was added to the drinking water of the chicks, which increased the total dietary silicon intake less than 0.5%. Despite this extremely low dose a significant effect was found on both the calcium concentration in the blood and the density of thigh bones (femura).

In fact, the chicks had, after six weeks supplementation, 5.6% higher bone density in the hip region and 4.25% higher bone density at the midshaft of their thigh bones compared to non-supplemental chicks. These results show clearly that stabilized silicon (choline-silicon complex) was able to stimulate the bone formation machinery resulting in a higher density.22

Based on all the current research, silicon is now being considered a critical nutrient to better manage the effects of age on the body. Increasing the silicon in your body can occur through foods, plant extracts or supplements. Those with osteoporosis should especially consider the benefits of consistent silicon intake.


1. Calisle EM. Silicon, an essential element for the chick. Science 1972, 178:619-62

2. Schwartz K, et al. Growth-promoting effects of silicon in rats. Nature 1972, 239:333-334.

3. Seaborn C, et al. Effects of germanium and silicon on bone mineralization. Biological Trace Element Res 1994, 42:151-164.

4. Seaborn C, et al. Silicon deprivation decreases collagen formation in wounds and bone, and ornithine transminase enzyme activity in liver. Biol Trace Elem Res 2002, 89(3):251-61.

5. Schwartz K. A bound form of silicon in glycosaminoglycans and polyuronides. Proc Nat Acad Sci USA 1973, 70(5):1608-1612.

6. Reginster J, et al. Long-term effects of glucosamine sulphate on osteoarthritis progression: a randomized, placebo-controlled clinical trial. Lancet 2001, 357:251-56.

7. Carlisle EM. Silicon: a possible factor in bone calcification. Science 1970, 167:179-280.

8. Hott M, et al. Short-term effects of organic silicon on trabecular bone in matue ovariectomized rats. Calcif Tissue Int 1993, 53:174-179.

9. Keeting et al. Zeolite A increases proliferation, differentiation, and transforming growth factor beta production in normal adult human osteoblast-like cells in vitro. J Bone and Miner Res 1992, 7(11):1281-1289.

10. Rico H, et al. Effect of silicon supplement on osteopenia induced by ovariectomy in rats. Calcif Tissue Int 1999, 66:53-55.

11. Eisinger J, Clariet D. Effects of silicon, fluoride, etidronate and magnesium on bone mineral density: a retrospective study. Magnesium Research 1993, 6(3):247-249.

12. Candy JM et al. Aluminosilicates and senile plague formation in Alzheimer's disease. Lancet 1986, 1:354-356.

13. Carlisle EM, Curran MJ. Effect of dietary silicon and aluminum on silicon and aluminum levels in rat brain. Alzheimer Dis Assoc Disord 1987, 1:83-89.

14. Jacmin-Gadda H, et al. Silica and aluminium in drinking water and cognitive impairment in the elderly. Epidermiology 1996, 7:281-285.

15. Loeper J, et al. Study of fatty acids in atheroma induced in rabbits by an atherogenic diet with or without silicon IV treatment . Life Sciences 1988, 42:2105-2112.

16. Loeper J, et al. The antiatheromatous action of silicon. Atherosclerosis 1979, 33:397-408.

17. Pennington JAT. Silicon in foods and diets. Food Addit Contam1991, 8:97-118.

18. Sangstet AG, et al. Silica in higher plants nutrition. In Silicon Biochemistry, CIBA Foundation Symposium 121, John Wiley and Sons, New York, p. 90-111.

19. Calomme M, Vanden Berghe D. Supplementation of calves with stabilized orthosilicic acid. Biol Trace Elem 1997, 56:153-156.

20. Calomme M, et al. Silicon absorption from stabilized orthosilicic acid and other supplements in healthy subjects. Trace elements in Man and Animals 10, ed by Roussel et al. Plenum, p. 1111-1114.

21. Van Dyck K, et al. Bioavailability of silicon from food and food supplements. Fresenius J Anal Chem 1999, 363:541-544.

22. Calomme M, et al. Effect of choline stabilized orthosilicic acid on bone density in chicks. Calcif Tissue Int 2002, 70:292.