Is silicon dioxide in supplements and food safe?

Silicon dioxide, also known as silica or SiO2, is a naturally occurring compound. It's made of silicon and oxygen. Both elements are abundant on our planet. Our bodies use silica to support the development of our bones, connective tissues, and more. 

Structure

In the majority of silicon dioxides, the silicon atom shows tetrahedral coordination, with four oxygen atoms surrounding a central Si atom. Thus, SiO2 forms 3-dimensional network solids in which each silicon atom is covalently bonded in a tetrahedral manner to 4 oxygen atoms. In contrast, CO2 is a linear molecule. The starkly different structures of the dioxides of carbon and silicon are a manifestation of the double bond rule.

Based on the crystal structural differences, silicon dioxide can be divided into two categories: crystalline and non-crystalline (amorphous). 

Natural occurrence

Silicon dioxide is most often recognized in the form of quartz. It’s found naturally in water, plants, animals, and the earth. The earth’s crust is 59 percent silica. It makes up more than 95 percent of known rocks on the planet. 

Silicon dioxide in food and supplements

Silicon dioxide is found naturally in many plants, such as:

leafy green vegetables

beets

bell peppers

brown rice

oats

alfalfa

Silicon dioxide is also added to many foods and supplements. As a food additive, it serves as an anticaking agent to avoid clumping. In supplements, it’s used to prevent the various powdered ingredients from sticking together.

Hazards

Inhaling a large amount of small particles of silicon dioxide, like in manufacturing situations, can adversely impact our health.

Otherwise, silicon dioxide is safe to use and consume in normal quantities. As always, the dose makes the poison.