So weird. Been bopping around your post and links and clicked to my desktop for a biz call. I found a page still open (must have been interrupted while reading it) - one which was linked by Ways of W here:
Silica Natural Beauty's Best Friend
Better Nutrition, May, 2000 by Karyn Siegel-Maier
Silica is not known to have any inherent toxic effects, but there has been a concern about the role it plays in the development of Alzheimer's disease. Earlier literature reports that elevated levels of silicon, as well as aluminum, have been found in the neurofibrillary tangles and plaques of Alzheimer's patients. However, more recent research suggests that normal serum levels of silica, especially in the presence of magnesium, may actually counteract the negative effects of aluminum in the body that may accumulate from processed foods, medicines, cookware or drinking water by interfering with the absorption and accelerating its excretion. There is also a suspected correlation between those of advanced years prone to Alzheimer's disease and the increased use of antacids and anti-inflammatory products, both of which can contain significant amounts of aluminum and silicon. And, as Regina Noble, B.A., M.S., a nutritional counselor based in upstate New York points out, "Silica is often used as a filler in many supplements, so I would review the supplements that the person is already taking. Prior to, or especially after, any supplementation the person should have a hair mineral analysis to determine the need, to see improvement and to check for excess." Since genetic factors play a major role in the potential to develop Alzheimer's, it would be wise to consult with a qualified healthcare practitioner before supplementing with silica if the disease is present in your family history.
The bottom line
Silica deficiency in humans has not been extensively studied. However, it is known that silica is essential to good health and a youthful appearance, and that the mineral becomes more important to our bodies as the years progress. If you suspect that you may not be getting sufficient amounts of this trace mineral in your diet, you may want to consider supplementation.
Pork rinds and beer?
Although it may seem "stranger than science" as veteran newsman Frank Edwards, used to say, pork rinds and beer are concentrated sources of silicon, although most nutritional adepts would frown on the former, at least.
Nevertheless, you need not look far to find (other) natural sources of silica, since Noble recommends that, "If a person has symptoms of silicon deficiency, such as very dry hair, of silica, including horsetail or oat-straw, or food sources, such as wheat bran, soybeans, beets, leafy vegetables and brown rice." However, keep in mind that the less adulterated the secondary source of silica is, the more benefits it will have to offer. So, strive to find organic, unprocessed sources of these products. Silica supplements containing standardized orthosilicic acid are also available, some fortified with silica partners such as magnesium, potassium and calcium.