Food grade diatomaceous earth is a fine, off-white powder made from the fossilized remains of diatoms, single-celled algae with hard silica shells that accumulated in freshwater and marine sediments over millions of years. It’s sold as a dietary supplement, a natural pest control product, and a general-purpose household powder, but the health claims surrounding it are largely unsupported by human research. Here’s what you should know before buying or using it.
What Food Grade Actually Means
Diatomaceous earth comes in two main forms: food grade and filter grade (also called industrial or pool grade). The difference matters. Filter grade is heat-treated, which changes its silica into a crystalline form that is dangerous to inhale and not safe for any kind of consumption. Food grade diatomaceous earth contains less than 1% crystalline silica and is mostly amorphous silica, which is far less reactive in the body.
The FDA lists diatomaceous earth as a substance added to food under CAS number 61790-53-2. It appears in multiple sections of the Code of Federal Regulations (21 CFR Parts 170–186), primarily as a filtering aid, anti-caking agent, and component in food packaging materials. It also carries a Generally Recognized as Safe (GRAS) designation under 21 CFR 182.90. That designation means it’s considered safe for its intended industrial food-processing uses. It does not mean the FDA has evaluated or approved it as a dietary supplement with health benefits.
How the Body Handles It
The main nutritional claim around food grade diatomaceous earth is that it provides bioavailable silica. Silica is a trace mineral involved in bone and connective tissue health, and diatomaceous earth is roughly 80–90% silica by weight. The idea is that stomach acid breaks down the silica into orthosilicic acid, the form your body can actually absorb.
A pilot human study published in Food & Function tested this directly. Researchers fed participants a meat product with added silicon from diatomaceous earth, then measured blood silicon levels during digestion. The result: serum silicon increased only very slightly, regardless of whether the food contained diatomaceous earth or not. The researchers concluded that absorption of silicon from diatomaceous earth is “insignificant” and that its low bioavailability had a “negligible effect on the absorption process.” In plain terms, the silica mostly passes through you. If you’re looking for a meaningful silica source, foods like whole grains, bananas, green beans, and mineral water deliver it in forms your body absorbs more readily.
Common Health Claims and the Evidence
Detoxification
One of the most popular claims is that diatomaceous earth “detoxes” the body by binding to heavy metals and pulling them out through digestion. This idea comes from a real industrial property: diatomaceous earth is an excellent filter for water treatment, where it traps heavy metals, bacteria, and sediment. But filtering water in an industrial setting and filtering toxins inside a living digestive system are very different processes. A 2023 review suggested silica may help filter out certain metals like aluminum, but no human research has confirmed this works during digestion or that it produces any meaningful health effect. The broader premise that your body is loaded with toxins requiring removal is itself not supported by evidence. Your liver and kidneys handle that job continuously.
Parasite and Gut Health
Diatomaceous earth has a long history of use as a natural dewormer in livestock, and some people take it hoping it will kill intestinal parasites. The mechanism makes intuitive sense: the microscopic sharp edges of diatom shells can physically damage the exoskeletons of insects and small organisms. Research does suggest diatomaceous earth can help control mites and internal worms in agricultural settings, particularly when combined with other methods. But controlled human studies confirming it works as an internal antiparasitic are lacking. Claims about improved gut health, reduced bloating, or better digestion remain anecdotal.
Cholesterol and Blood Pressure
A small, older study is often cited showing that women who took diatomaceous earth daily experienced modest reductions in cholesterol. That study has not been replicated, and its small sample size makes it difficult to draw reliable conclusions. No major health organization recommends diatomaceous earth for cardiovascular health.
Safety Concerns Worth Knowing
There is currently no established safe dosage for diatomaceous earth in humans. Despite widespread online recommendations (often suggesting one teaspoon to one tablespoon per day mixed into water), these doses are not based on clinical research. No regulatory body has determined an appropriate dose range for children or adults as a supplement.
The most well-documented risk involves the lungs. People who work with diatomaceous earth in large quantities face serious respiratory problems, including an increased risk of lung cancer from prolonged inhalation. Even food grade powder is extremely fine and easy to breathe in while handling it. If you do use it, mixing it into liquid rather than scooping dry powder in an enclosed space reduces airborne dust.
Skin contact with the dry powder can cause irritation, dryness, or small abrasions because of its mildly abrasive texture. Some users report constipation, which is consistent with consuming a powder that absorbs moisture in the digestive tract. Drinking extra water when taking it is commonly recommended for this reason, though even that guidance comes from user experience rather than clinical study.
Heavy Metal Contamination
Because diatomaceous earth is mined from natural deposits, it can contain trace heavy metals from the surrounding geology. Laboratory analysis of diatomite samples has found lead concentrations as high as 105 mg/kg and cadmium at roughly 3.9 mg/kg, levels that significantly exceed maximum allowable concentrations for mineral additives in some regulatory frameworks. Not all deposits are the same, and reputable supplement brands test their products for contaminants. If you’re purchasing food grade diatomaceous earth for consumption, look for products that publish third-party lab results showing heavy metal levels, particularly for lead, arsenic, and cadmium.
Practical Uses With Stronger Evidence
Where food grade diatomaceous earth does have a solid track record is pest control. The powder works by absorbing the waxy outer layer of insects’ exoskeletons, causing them to dehydrate and die. It’s effective against ants, cockroaches, bed bugs, fleas, and other crawling insects when applied as a thin, dry layer in areas where they travel. It loses effectiveness when wet. For this purpose, food grade is preferred over filter grade in homes with pets or children, since incidental contact or ingestion of small amounts is less hazardous.
It also works well as a natural deodorizer, a gentle abrasive for cleaning, and a moisture absorber in stored grains or pet food. These practical applications are straightforward and don’t rely on unproven health mechanisms. For most people, these uses represent the clearest value of the product.