Surprise – silicon necessary for bone health

Abundant silicon needed for bone health (Photo: Wikimedia)

Abundant silicon needed for bone health (Photo: Wikimedia)

Surprise, surprise – we might all need silicon in the diet to form healthy bones, not just to build computers. Fortunately, over 90% of the Earth’s crust is composed of silicate minerals, making silicon the second most abundant element in the Earth’s crust after oxygen. Far from eating it all,  most free silicon is used in the steel refining, aluminum-casting, and fine chemical industries. Critical is the small proportion of highly purified silicon used in semiconductor electronics forming integrated circuits in computers. But it is also used in many other applications like building materials, whiteware ceramics such as porcelain, and in traditional quartz-based soda-lime glass. Silicon is the basis for polymers called silicones that are used among other things for breast implants, but remember silicon and silicone is not the same thing.

The biological role of silicon

Forget the industrial applications, we are interested in the food aspects of silicon. And here it has been proven that it is an essential element in biology, although only tiny traces of it appear to be required. Studies of silicon deprivation in growing animals conducted in the early 1970s showed reduced growth and marked defects of bone and connective tissue. In addition, silicon supplementation of postmenopausal women with osteoporosis not only inhibited bone resorption but also increased trabecular bone volume and bone mineral density. All good things.

Thus, there are clear evidence that silicon plays a major role in bone formation, yet there has been a question mark around important dietary sources of silicon that can actually be absorbed by the body. Indeed, it has been assumed that silicon, as the bioavailable orthosilicic acid, is present only in fluids (such as drinking water and beer) but not in foods, in which it exists as polymeric or phytolithic silica.

The benefits of beer

High silicon levels in beer (Photo: cizauskas)

High silicon levels in beer (Photo: cizauskas)

Beer appears to be a major contributor to silicon intake. Researchers have published findings from a study of commercial beer production looking at the relationship between beer production methods and the resulting silicon content. The study examined a wide range of beer styles for their silicon content and also looked at the impact of raw materials and the brewing process on the quantities of silicon that enter wort and beer.

A previous study had shown that silicon in beer is readily bioavailable because it is solubilised during the mashing process of beer making. The new research noticed little change in the silicon content of barley during the subsequent malting. The majority of the silicon in barley can be found in the husk, which wasn’t affected much by the malting process. Samples of hops showed surprisingly high levels of silicon with as much as four times more silicon than is found in malt. However, hops are normally used in a much smaller quantities than barley. But if you want to optimise silicon intake you should go for beers produced using a higher hops content since the final beer proved to contain higher silicon levels. Testing of commercial beers showed that the silicon content in the final product could vary between 6.4 to 56.5 mg per litre, close to a ten times difference.

Based on these findings, some studies suggest moderate beer consumption may help fight osteoporosis, a disease of the skeletal system characterised by low bone mass and deterioration of bone tissue. It has also been shown that men have a higher silicon intake than women, mainly due to a higher beer consumption contributing to 45% of their total silicon intake. Good news for beer drinkers you might think.

All is not lost if you don’t drink beer

The high silicon levels in bananas is not bioavailable (Photo: robin_24)

The silicon in bananas is unfortunately not bioavailable (Photo: robin_24)

But what about if you don’t drink beer? Not to worry. It has been shown that the silicon in solid foods can be hydrolysed to bioavailable orthosilicic acid in the gastrointestinal tract. A study of different food sources found that silicon in grains and grain products (rice, breakfast cereals, breads, and pasta) was readily absorbed. However, except for green beans and raisins, the silicon in vegetables and fruit was less readily absorbed. Surprisingly, silicon absorption was low from bananas, which are high in silicon and could have replaced beer as the number one source.

Before you get concerned about your silicon intake, it should be clear that silicon deficiency has not been observed in humans. Such a fact doesn’t discourage food supplement manufacturers. There are a range of silicon supplements on the market with claims like:

  • improving cell metabolism and stimulating cell formation;
  • inhibiting the ageing process by supplementing tissue silica that rapidly decreases with age;
  • strengthen weak connective tissue by improving its structure and function;
  • increasing the elasticity and firmness of blood vessels, making them less likely to develop atherosclerosis;
  • enhancing the appearance of hair and nails as well as skin.

Such food supplements might not do much damage since toxicity of silicon is very low. However, it will be a waste of your money since the normal diet should provide sufficient silicon anyway. Your call, but a glass of beer now and then might be cheaper.

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About food science guru
A public health veterinarian and past professor in food safety with life-long experience at national and international levels. Instrumental in assessing public health exposure to beneficial and hazardous chemicals and microorganisms as part of risk assessments.

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