Diatomaceous Earth (Food Grade)

Diatomaceous earth (food grade) is composed primarily of amorphous silica (silicon dioxide, SiO₂), typically comprising 80–94% of the total composition. It is not a significant source of macronutrients (protein, fat, carbohydrates, or fiber are essentially absent). Key mineral constituents include: **Silicon (as SiO₂):** ~80–94% — the dominant bioactive component; orthosilicic acid, the bioavailable form of silicon, may be released in small amounts upon contact with gastric acid, though bioavailability from solid amorphous silica is generally considered low (estimated <5–10% conversion to absorbable orthosilicic acid). **Trace minerals (approximate ranges per 100 g):** Alumina (Al₂O₃): 1–5%; Iron oxide (Fe₂O₃): 0.5–2%; Calcium oxide (CaO): 0.3–1.5%; Magnesium oxide (MgO): 0.2–1%; Sodium oxide (Na₂O): 0.2–1%; Potassium oxide (K₂O): 0.1–0.5%; Titanium dioxide (TiO₂): 0.1–0.3%; Phosphorus pentoxide (P₂O₅): 0.1–0.3%. These trace minerals are largely bound in the siliceous matrix and have limited bioavailability. **Caloric value:** Essentially zero (non-digestible, inert mineral). **Vitamins:** None present. **Bioactive compounds:** The primary bioactive mechanism is physical/mechanical rather than chemical — the microscopic porous diatom frustules have high surface area (~20–50 m²/g) and negative charge, which may facilitate adsorption of certain organic compounds, heavy metals (e.g., lead, mercury, cadmium), and endotoxins in the gastrointestinal tract. **Bioavailability notes:** The silicon in diatomaceous earth is predominantly in an insoluble amorphous form; only a small fraction is hydrolyzed to bioavailable orthosilicic acid (Si(OH)₄) under physiological pH conditions. One human study (Jurna et al., 1998) showed modest increases in serum silicon after supplementation, suggesting limited but measurable absorption. Typical recommended daily intake is 1–3 teaspoons (~3–10 g), yielding roughly 2.5–9 g of SiO₂, of which perhaps 100–500 mg of silicon equivalent may become partially bioavailable. The mineral is non-caloric and passes largely intact through the GI tract, functioning primarily as a physical adsorbent rather than a conventional nutrient source.