Ask PLAN's ArwenIf your diatomaceous earth is called “food-grade”, why can’t I eat it?
There are two types of diatomaceous earth (DE) that are commercially available. “Food-grade”, or natural, DE is dried at a low heat with no additives. Food-grade/natural DE is very low in crystalline silica (the dangerous type of silica) and is very safe to use and handle. The other type of DE is called “pool-grade”, “filter-grade”, or calcined. When DE undergoes the calcining process, it is treated at a very high heat that increases the crystalline silica content.
At Progressive Planet, all our DE products are natural and non-calcined, and their crystalline silica content is less than 1%. Our DE has been approved as an animal-feed additive for over 25 years. However, we have not conducted the clinical studies required for human consumption, so our DE has not yet been approved for human use.