Silica Stories by Christina De La Rocha & Daniel J. Conley

Author:Christina De La Rocha & Daniel J. Conley
Language: eng
Format: epub
Publisher: Springer International Publishing, Cham

6.4 Collagen

So how did we get from thinking of silica as being bad for the body to thinking it might be necessary? The simplest irrefutable way to figure out if a substance is required by an organism is to withhold it and see if the creature fails to thrive. This is what Edith Carlisle did so successfully in her chick experiment of the early 1970s. But we still don’t know why she did the experiment. Yes, because of King and his colleagues, she knew that silica could be absorbed into the bloodstream, transported about the body, and eventually excreted in the urine. But it’s still a huge leap to think silica might be needed by chickens. What brought her to it?

Prior to the great chick experiment and her interest in silica, Edith Carlisle had been interested in the mineralization of bone. She spent years meticulously slicing and mounting thin sections of growing bone taken from young rats. She examined these thin sections using an electron microprobe, a nifty machine, still in widespread use even after all this time and further technological progress. With the electron microprobe, Edith Carlisle could measure the basic chemical composition of micro-sized areas of her samples. Over and over again and to her utter surprise she saw that silica was highly concentrated in bone’s actively calcifying areas. To her this meant that silica was playing an active and critical role in bone growth. This, then, was what inspired her to starve some chicks of silica to see if it was true.

Go back to the photo of the chicks one month into their different diets (Fig. 6.1). The results scream loud and clear. Silica-deprived chicks can’t properly biomineralize their bones. Not only do these chicks grow only short and scrawny, their skulls are deformed, and they can’t do better than a bedraggled set of feathers. When you dissect the silica-starved chicks, inspecting everything very closely, you find that their bones, connective tissues, and blood vessels contain significantly less collagen than they should. As we’ve said, the poor things can’t even hold up their heads.

Save for the bit about the feathers, the same story holds true for rats. Recently born rats raised without adequate silica also form deformed skulls and the bones, etc., they grow are also short on collagen.

Later rat experiments went further, wounding the rats so the healing process could be observed.6 The wounds of the silica-starved rats healed slowly and with significantly less collagen (and biochemical precursors to collagen) than the wounds of rats adequately supplied with silica.

The inescapable conclusion is that silica-deficiency makes it hard to make collagen. It’s an answer that isn’t yet an ultimate answer. It generates more questions than it addresses. Honestly, what on Earth does this triple helix of a protein have to do with silica? There is absolutely no obvious logical connection between the two things.

Perhaps you only know collagen as something to be injected in lips, as something to be hydrolyzed to make gelatin, or as the gelatinous gloop you get when you boil down meat scraps and bones for soup.

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