The word silicon conveys different things to different people. It is the very foundation of the IT industry with silicon chips becoming indispensable for the computing industry. For a chemist it is an element in the Periodic Table, some what inert, a major constituent of sand and the raw material for making glass. Silicon oil is much valued by the machine operators because of its lubricating properties even at high temperatures. Silicon rubber, high temperature resistant is becoming a part of modern kitchen accessories. Silicon implants raises the vision of beauty for women through implants that improve the vital statistics. Presence of sand and pebbles in foods is an aversion for consumers. Till recently nutritionists were unconcerned about silicon as it was thought to have no role in human health.
A recent report that eulogized the practice of drinking beer regularly for the beneficial effect it has on health has kindled more interest in the role of silicon in human metabolism. According to National Institute of Health, USA beer is a major contributor of the micro nutrient and trace mineral silicon which is important for the growth of bone and connective tissue. Some medical experts even suggest that moderate consumption of beer may help in meeting the challenge posed by osteoporosis which affects the skeletal system through low bone mass and weak bone tissue. Of course this observation has some relevance in Western countries where beer is a part of regular life style. The advent of "Growlers" in cities like New York where beer is sold through taps in the vending outlets, to be taken out with large 64 oz glass containers looking like an over sized mug, possibly may improve the bone health and other disorders attributed to silicon significantly.
Silicon shot into prominence during 1970s when its role in animal nutrition was discovered and since then lot of work has gone into unraveling the mystery that surrounds involvement of silicon in human health. Silicon is a macro nutrient for plant cell growth and plant foods contain this mineral in good concentrations. Silicon deficiency is known to cause abnormal bone formation in experimental animals though its deficiency in humans has not yet been extensively documented. But human body contains about 7 gm of silicon on an average, demonstrating an important role for this chemically inactive inorganic material. Scattered studies involving silicon's role in human metabolism have demonstrated its role in developing strong bones and cartilages, aiding skin growth and ensuring strong joints. Further it is believed to be helpful in boosting the benefits of calcium, glucosamine and vitamin D in developing stronger bone.
Silicon present in tissues has been found to be bonded to glycoproteins like cartilage while blood silicon is in the form of free orthosilicic acid or linked to small compounds for ready use. The mechanism of action seems to be through reduction in permeability of extra cellular matrix in connective tissues including arteries, trachea, tendon, bone, teeth and skin. It also has catalytic role in bone mineralization, facilitation of healing process and building immune system. Data on silicon intake amongst population are limited. In the US the average intake is reported to be 19 mg per day through diet for women and 40 mg for men. Though there is not yet any universally acceptable daily intake value, a level of 5 mg to 50 mg per day has been suggested by various experts. No harm is anticipated even if consumption reaches 700 mg per day.
Water is a major source of silicon and normally 2 liters of drinking water can provide the daily needs of this trace mineral. Silicon content in water can vary between 6.4 mg to 56.5 mg per liter depending on its source. Extreme purification of potable water can remove most of the silicon present, a practice not considered desirable. Foods like oats (4.25 gm per kg), barley (2.54 gm per kg) and whole cereals many fruits and vegetables, nuts, milk and honey. Human milk has significant levels of silicon with very high bioavailability where as silicon from other sources has very low bioavailability. Modern processing of cereals into refined products by removing the husk and the bran makes them still worse as a source of silicon. It is no wonder that those babies on mothers' milk for a minimum of 6 months grow to become healthy for their entire life duration, compared to those weaned away or do not have the benefit of breast feeding.
Beer is now considered as one of the most important sources of silicon which is derived from the barley and hops used for brewing. Pale colored barley has highest silicon content and during brewing process the bioavailability of silicon increases significantly. Attempts to market low alcohol or alcohol free beer by the industry raises the inevitable question whether such products will contain same levels of silicon as normal ones because the actual mechanism involved in increasing the bioavailability during brewing is not fully understood. Probably lot of new developments can be expected on silicon nutrition in the coming years. The day may not be too far away when the humble beer is promoted as a health product rather than as a refreshing alcoholic beverage!