Silica (SiO) is the second most abundant element in the Earth’s crust. Though often referred to as Silicon (Si), Silica is actually bonded Silicon. It molecularly bonds to oxygen in a ratio of four oxygen atoms to each silicon atom to form silica. And due to it’s affinity for oxygen, silicon in its elemental form is actually very rare. But silica is actually an important base mineral in the health of our connective tissue.
Silicon or silica may also be confused with silicone, which are the familiar rubbery man made materials, which are chemically constructed from a base of SiO-Si (silica and silicon).
30 years of research says silica has essential health benefits
Silica is the most abundant trace mineral in the body after iron and zinc, and present in connective tissues, teeth, hair, bones, heart, lungs and liver to name a few.
It was listed as an essential trace mineral in 1972, and has many decades of research providing evidence that dietary silica is not only beneficial but necessary.
It is essential to the production of healthy bone, teeth, and connective tissue, including tendons, cartilage, and blood vessels.
The form of silica present in the body is orthosilicic acid, a derived form of silica that has been shown to increase the benefits of vitamin D, glucosomine and calcium.
It is even a component of glycosaminoglycans (GAGs) which facilitate the regeneration of collagen. Silica is a major component of collagen, as well as nails and hair, and essential for the health and regeneration of both. Therefore, silica supplements are popular for their anti-aging effects..
Evidence exists of silica’s involvement not only in collagen synthesis, but calcium absorption as well.
Some research suggests that silica controls the metabolism of calcium and magnesium. A French chemist and Nobel Prize nominee, Louis Kervran, postulates that supplemental silicon can improve calcium uptake through the actions of enzymes.
Studies have even suggested that Silica may counteract aluminum in the system, possibly preventing Alheimer’s disease and other cognitive decline.
We are exposed to silica and silicon daily with dust, pharmaceuticals, and cosmetics. But our uptake is primarily through food and water.
Why silica is now less prevalent in plant food sources
While levels of Silica’s soluble and bioavailable form, orthosilicic acid, are much lower in plants than the levels of silica in soils, researchers have seen diminishing levels of this orthosilicic acid in food sources in recent decades.
It has been concluded that this decline is due to industrialized farming, mono farming, and the use of pesticides and certain fertilizers, all resulting in the elimination of a certain microbe species from the soil that assimilates silica into its bioavailable form.
These species are known to dissolve silica into the orthosilicic acid, the form of silicon available for uptake into vegetation and into our bodies. It is this silicic acid that is missing in the soil, pointing to the eliminated microbes from industrialized farming.
Water and other fluid sources of silica
Drinking water and other fluids provide the most readily bioavailable source of Si in the diet, and can account for at least 20% of the total dietary intake of Si.
Silicon in drinking water is derived from the weathering of rocks and soil minerals and since different types of minerals weather at different rates, the concentration of Si in water is dependent upon the surrounding geology. Higher quantities are found in hard water and comparatively less in soft water.
Beer and coffee are also high in silica, beer being particularly high in silica as it is made from silica rich grain.
Food sources of silica
High levels of silica are found in unrefined whole grains, legumes, seafood (particularly mussels), nuts, and many vegetables. Higher concentrations of silica are found in plant fiber than are found in meat or dairy products.
Fruits contain low levels of silica, with bananas, apples, oranges, and strawberries being some of the higher fruit silica sources. Higher concentrations are found in vegetables such as green beans, cabbage, celery, onions, carrots, parsnips, cucumber (especially the skin), spinach, tomatoes, pumpkin, radishes, beets, wheatgrass, alfalfa, and some herbs.
Grasses such as bamboo, alfalfa, and horsetail are much higher in silica than other vegetables, accumulating 10-20 times silica.
Horsetail (also known as shavegrass) is regularly prescribed in teas by herbalists for skeletal disorders, problems with connective tissues, and even broken bones.
Teas with horsetail have even been reported to be beneficial to tooth enamel (however, high thiaminase levels in horsetail necessitate simmering it in water for ten minutes to neutralize this poisonous enzyme).
Normal dietary intake of Si is between 20-50 mg Si/day for most Western populations. And although this is a greater than 2-fold higher intake over iron and zinc, China and India, where a higher plant based diet is typical, have reportedly higher intakes (140-204 mg/day).
Silica dioxide in food grade diatomaceous earth
While orthosilicic acid is the organic form of silica obtained from food sources, another source rich in silica is the non-organic Diatomaceous Earth (silica or silicon dioxide (SiO2)).
Diatomaceous Earth (DE) is not actually earth or dirt, but formed by fossilized exoskeletal shells of microscopic one-celled aquatic plants, an algae called diatoms.
The remains of these diatoms is a chalky, clay-like substance, a mineral sediment, sometimes referred to as diatomite, that produces extremely pure and consistent DE. To be classified as food grade, this sediment must contain around 85% amorphous (non-crystaline) silica.
Of the 600 deposits of DE in the US, only four are classified as food grade, which means generally regarded as safe (GRAS) by the FDA.
And within the food grade category, there is a difference between the fresh and salt water deposits, and how finely it if sifted. The best food grade DE will be a fine whitish powder that is odorless and tasteless, with between 85 and 92% silicon dioxide, along with other trace minerals. But some DE products may contain as much as 33% clay, making them less effective.
Care should be taken when ingesting diatomaceous earth that it is indeed food grade. Non-food grade DE can contain harmful minerals and inorganic matter.
What about taking a silica supplement?
Several studies have shown the benefits of supplemental silica. For example, silicon supplementation in subjects with osteoporosis resulted in increased bone volume and increases in femoral and lumbar spine BMD.
While the daily recommended amount for adults is less than 30 mg, there are no known symptoms or diseases of silicon excess in humans.
And although , the upper limit to avoid toxicity is listed at 700 mg. it is sometimes recommended in supplemental doses as high as 250-750 mg. For example, the informational literature provided with the Penguin Cold Cap, used to help chemotherapy patients retain their head of hair, recommends 25o mg three times per day to strengthen the hair follicles.
Any excess of silica that not utilized by the body is removed through the bloodstream, renal system and digestive tract. Therefore, it is said that most people with healthy renal function should not have an issue taking silica supplements in reasonable amounts for a non-extended period.
Recommended daily intake of silica and silica supplement advice
Supplement in tablet and solution forms have shown varying degrees of bioavailability (between 1 and 50%), with most showing negligible-low bioavailability. So buy products made by an established, well reputed company, selecting only products with standardized extracts or guaranteed potency.
The Food Standards Agency UK suggests an upper limit of 700mg per day should not produce harmful side effects in most people. But as studies are not exhaustive, excessive levels should not be taken long term, and only under medical supervision for a known silica deficiency. And as always, supplementation should always be taken with adequate water.
One species of horsetail, Equisetum palustre, is poisonous to horses, and so to be safe should be avoided altogether. Other varieties such as Equisetum Arvense have no known adverse effects.
Contra indications of silica and horsetail supplements
Although there are no known symptoms or diseases of silicon excess in humans, long-term use of high doses of silicate containing pharmaceuticals, such as analgesics and antacids (magnesium trisilicates) could damage renal kidney tubules, leading to chronic interstitial nephritis.
This suggests that people with renal trouble avoid taking large doses of silica supplements. Long-term use or very high doses of even the commonly used horsetail supplements have caused irreversible kidney damage, especially in people with existing kidney or heart disease.
People with fluid retention (edema or oedema) should not be taking silica (or horsetail) supplements. Women who are pregnant or breastfeeding and children should not take any silica (or horsetail) supplements due to the possible adverse effects and only obtain their silica from food, as the safety of excessive levels of silica has not been tested thoroughly and caution is advised.
I began taking a silica supplement containing 97% food grade diatomaceous earth along with horsetail and bamboo shoot, and within a few weeks was surprised to notice a definite increase in my eyelashes, which had been all but absent on the outer half of my lower lids for years. They are now not only present, but all of them are even more recently noticeably thick and longer, after about 4 or 5 months, indicating to me a benefit not only to the health of my hair, but to my skin, nails, connective tissue and bones as well.