SILICON—vital trace mineral SILICON
by Lynn Hinderliter CN, LDN


With reference also to an interview given by him and Dr. Mario Calomme to Dr. Passwater in the December 1998 issue of WHOLE FOODS magazine.

Perhaps it is inevitable that, now we have untangled the complex roles of the major minerals in the health and functioning of our bodies, our attention would turn to the trace minerals. Even though the amounts in which they are present are relatively tiny, the complex effects they have are impressive.

The importance of silicon for structural strength in plants has been fairly well known, researched and demonstrated, and indeed one of the first supplementary forms of silicon was from the horsetail plant. Silicon forms app. 28% of the earth’s surface, and it is present in clay, sand, rocks, sea water, and as mentioned, in the fibers of plants. This latter, however, assumes the presence of silicon in the soil which grew the plants.

In the 1970s, some interesting research with animals brought to light a possible connection between inferior development, structural abnormalities, and poor cartilage and bone structure in animals receiving a diet deficient in silicon. Drs. Carlisle & Schwarz found that chicks and rats on a silicon deficient diet were smaller and developed severe skeletal malformations which were preventable with silicon supplementation . That this would also be relevant to humans was hinted at by a discovery of Mourkazel in 1992 that pediatric patients fed parenterally showed a decreased serum silicon concentration coincident with decreased bone mineral content.

Total Parenteral Nutrition

(Moukarzel at al, J. Am. Coll. Nutr. , 11, 601, 1992)

Group Si in serum (ppb) Relative BMC (%)


Controls 547 (155—1306) 100

TPN (n=25)** 207* (106—376) 77.5


*p<0.001 versus controls ** daily dietary intake of TPN: 0.6—1.2 mg Si

In the United States, the mean daily silicon intake is between 20 and 50 mg (established by Pennington in 1991), a figure which is considerably less in this era of refined foods, where the removal of the plant and grain fibers from the diet has lowered the silicon content. The largest sources of dietary Si are grains, beverages (particularly beer) and vegetables. Dairy foods, poultry fish and meat contain relatively little of the element.

The human body contains app. 7 gms of Si, with the serum content ranging from 0.2 to 4.0 ppm. (Bercowy, 1994)

It is present in the tissues as follows (Creach 1990)

Tissue Si (ppm, d.w.)

Kidney 40

Liver 33

Spleen 131

Lymph nodes 489

Thymus 1452

Adrenal glands 1170

Skin 23

Nails 56

(N.B. I find the high figures for the thymus and adrenals particularly interesting, with the corresponding implications for immune function and stress control. LFH)

Silicon and Bone Formation

The 1970 experiments of Carlisle & Schwartz found a correlation between the amount of Si in the diet and the mineralization level of the young bone. Si was found to be located uniquely in the areas where active growth was taking place, declining in relationship to the laying down of hydroxyapatite, or bone crystal, which is the process that transforms young, pliable bone into a hard , calcified structure. This lead the Doctors to hypothesize that Siclicon acted a s a regulating factor for the deposit of bone.

The process of bone adsorption and formation is at all times dynamic. Osteoporosis occurs when the rate of bone breakdown by osteoclasts outpaces the rate of bone building by osteoblasts. A 1993 study done in Paris by Dr. Marie dealt with Si supplementation in estrogen deficient rats. The ovaries were removed surgically, and true bone loss was observed both as loss of bone volume, and an increase in osteoclasts as compared to controls. One finding was that Si supplementation significantly reduced the rate of bone loss, from 48% in unsupplemented rats to 34% in those receiving Si.

Ovariectomized rats

Animal model for osteoporosis (Hott et al, 53, 174 1993.)


Rats # osteoclast surface osteoclast #

Control …………… 20 4.1 1.8

Ovariectomized ……. 10 8.8* 2.2

Ovariectomized +

Estradiol ….. 10 5.3** 1.7**

Ovariectomized +

Silicon (1mg/kg/day … 10 6.1 *,** 1.7**


p< 0.05 versus control **p< 0.05 versus ovariectomized

In another French study, 8 osteoporotic women received bi-weekly injections of 50 mg of Si twice a week for 4 months . The bone mineral density of the femur increased by 4.7% over the course of the treatment. (Eisinger et al, Magn. Res., 6, 1993)

As well as these two in vivo studies, in vitro results have also been suggestive of an important role for Si in bone remodeling. Dr. Riggs et al (Mayo Clinic, Rochester) showed that a silicon containing compound stimulated the DNA synthesis in osteoblast-like cells, at the same time inhibiting osteoclast mediated bone resorption.

Silicon and connective tissue

The work of Dr. Carlile showed that Si was present in decreased amounts in animals presenting with bone and cartilage malformations. It appears that the two fibrous proteins necessary for healthy connective tissue, i.e. collagen and elastin, and also the glycosaminoglycans , are dependent on a specific enzyme, prolyl hydroxylase, for connective tissue synthesis. Not only is this enzyme lower in silicon deficient tissues, but it increases when silicon is added. When Dr. Schwartz found silicon present in GAGs, he hypothesized that it has a cross-linking role to stabilize the network. Collagen synthesis and GAG formation are therefore both adversely affected by a Si deficiency. Dr. Calomme suggests that making sure silicon is available in conjunction with Glucosamine and Chondroitin could be useful in the treatment of connective tissue disorders.

Silicon and Cardiovascular Disease

There have been several suggestive studies which indicate that silicon may play a part in heart health. In France, supplementation with Si has prevented the formation of plaque in the arteries of rabbits. The aortas of the animals receiving the Si were undamaged, where the controls receiving cholesterol showed thinning and fragmenting elastin fibers. Of 31 animals receiving a high cholesterol diet alone, 77.4% were found to have atheromatous aortas. Of 38 animals fed the same diet supplemented with Si, 23.7% showed arterial damage. (Loeper at al, Atherosclerosis, 33,397,1979) It would be possible to extrapolate from this that preventing damage to the artery through Si supplementation would inhibit the laying down of plaque which frequently follows injury to the artery wall. In France the consumption of high fiber foods, hard water and wine provides a rich source of silicon, possibly indicating a bit player in the French Paradox, whereas in Finland, the inverse relationship between low Si in the water and high levels of heart disease would also prove a connection. More research is needed in this area.

Silicon and Neurological Disorders

While it has not yet been proved conclusively that Aluminum is a factor in Alzheimer’s disease, it does remain a possible player in the development of the disease. A study by Jacqmin ( Epidemiology, 7, 281, 1996) of 3777 subjects 65 and older, showed that aluminum affected cognitive impairment when Si was low in the drinking water, and when the Si level was high, it provided a protective effect. An animal study (Carlisle , Alz. Dis. Ass. Dis., 1, 83, 1987) also showed that decreased amounts of Si in the diet led to increased amounts of Al in the tissues. Where aluminum was added in the presence of a normal amount of Si, there was no increase in the Al level.

Silica versus Silicon

A good deal of confusion exists because of the two forms of silicon: the first, silica, known as silicon dioxide, is basically sand. This form is bound to oxygen, and metals such as aluminum. The second form of silicon is Orthosilicic acid, found, for example, in sea water. Plants absorb Orthosilicic acid from the soil and convert it into polymeric phytolytic silicates. The question is, how absorbable is this form of silicon? Dr. Vanden Berghe points out that while the silicon content of such a substance may be high, the absorbability can be quite low since polymers are poorly absorbed, and require a combination of hydrochloric acid and other stomach enzymes to become available to the body. This means that aging, nearly always accompanied by poor digestive status, inevitably leads to diminished silicon status also.

Orthosilicic acid, on the other hand, is a monomer. This , however, raised its own problems, since a monomer is always unstable, and in fact concentrations of Orthosilicic acid without stabilization always leads to polymers. Dr. Vanden Berghe developed a method for stabilizing the monomer form of Orthosilicic acid with choline chloride and glycerol, resulting in a concentration of OSA about 30,000 times greater than that in sea water. Some studies to show the biological availability of OSA follow.

Supplementation of Calves with Stabilized Orthosilicic Acid—23 week study to show bioavailability of OA



►70% higher Si in serum P=0.0001


Collagen in dermis of calves—effect of Orthosilicic Acid (23 wks)

12.5% higher collagen P= 0.019

Calomme and Vanden Berghe (1997), Biol. Trace Elem. Res,. 56, 153-165

Supplemental sources of silicon

Silicon is usually supplemented in I of 3 available forms: colloidal silica, standardized horsetail herb, or BioSil. Dr. Vanden Berghe devised a test to check for the comparative bioavailability of these 3 sources, using 14 healthy volunteers on a normal diet, using a crossover double blind format.

Area Under the Curve—Measure of Resorption


A.U.C. (µg h/L)

———————— ———————————————————————————————————–

Urinary Silicon Excretion


Si excretion (µgSi/g creatinine) P<0.005


Calomme. MR et al. (1998) JPN, 22, S12


While silicon has not yet been officially designated a mineral essential for life, there can be little doubt that compelling evidence exists to substantiate a claim to that status . A dietary silicon deficiency has been shown to cause a decrease in articular cartilage, decrease in levels of collagen, GAGs and Calcium, abnormal structure of the skull, joints and long bones , and a decrease in bone Hydroxyproline. Positive effects of OSA supplementation have been shown to include: limiting the toxicity of aluminum, antiatheromatous action, stimulation of osteobalsts with a concomitant inhibition of osteoclasts, hypocholesteromic effects, offsetting the lowered BMC effect of TPR, and stimulating growth and health of hair and nails.

Toxicity of Silicon

Silicon has proven to be non-toxic in rat trials at doses up to LD50.