Understanding Diatomaceous Earth: The Crucial Grade Distinction
Diatomaceous earth is a naturally occurring soft sedimentary rock that, when crumbled, becomes a fine, off-white powder. It is formed over millions of years from the fossilized remains of diatoms, which are microscopic, single-celled algae. The hard outer shells of these diatoms are made primarily of silica, giving DE its unique properties. The crucial difference between DE products lies in their processing, which results in two main grades: food grade and filter grade.
Food-grade DE is sourced from freshwater deposits and is minimally processed. It is uncalcined, meaning it is not subjected to extreme heat. This process keeps its silica in an amorphous (non-crystalline) form, which is generally considered safe for human and animal use. The U.S. Food Chemicals Codex (FCC) sets the standards for food-grade DE, requiring it to contain less than 1% crystalline silica and meet strict heavy metal content specifications.
Filter-grade DE, on the other hand, is often sourced from saltwater deposits and is heat-treated through a process called calcination. This high-temperature treatment converts the amorphous silica into crystalline silica, which improves the DE's filtration capabilities but makes it highly dangerous if inhaled. Crystalline silica particles can accumulate in the lungs and cause serious health issues like silicosis. This grade should never be used for anything other than its intended industrial purpose.
Comparing Food Grade and Filter Grade Diatomaceous Earth
| Feature | Food Grade Diatomaceous Earth | Filter Grade Diatomaceous Earth |
|---|---|---|
| Source | Freshwater deposits (uncalcined) | Often saltwater deposits (calcined) |
| Silica Form | Primarily Amorphous Silica | High Crystalline Silica (>60%) |
| Processing | Sun-dried, minimally processed | Heat-treated (calcined) at high temperatures |
| Safety | Generally Recognized as Safe (GRAS) by the FDA for indirect use and safe for consumption in small amounts; safe for use around humans and animals | Toxic if inhaled; should only be used for industrial filtration |
| Uses | Dietary supplement, natural insecticide, anti-caking agent in animal feed, natural cleaner | Pool and water filtration, industrial purposes |
| Inhalation Risk | Avoid inhaling dust, can cause temporary irritation | High risk of serious lung damage (silicosis) if inhaled |
The Nutritional and Health Claims of Food Grade DE
Many anecdotal reports and marketing claims suggest various health benefits from ingesting food-grade DE. The primary rationale is its high concentration of silica, a mineral that some believe supports bone health, hair and nail strength, and detoxification. However, concrete scientific evidence supporting many of these claims is very limited, and some reports are based on unverified information.
- Digestive Support and Detoxification: Proponents suggest that food-grade DE’s abrasive, hollow, porous nature acts as a gentle cleanser for the digestive tract, helping to sweep away impurities. It is also theorized to bind with and remove heavy metals, although human research is lacking. Your body has its own detoxification systems, and these claims are not medically proven.
- Bone Health: As bones contain silica, some argue that DE supplementation aids bone formation and repair. Some animal studies and reviews show a link between silicon intake and bone health, but it's not clear how much is absorbed from DE or if it benefits humans.
- Skin, Hair, and Nail Health: Since silica is found in hair, skin, and nails, many believe DE can improve their strength and appearance. Again, scientific evidence is largely anecdotal, and sufficient absorption is unconfirmed.
- Cholesterol Reduction: One small 1998 study, with limitations due to a lack of a control group, suggested DE might help lower cholesterol levels. No significant follow-up research has confirmed this effect.
Safety Precautions and Proper Usage
Despite being considered safe for ingestion in small amounts, handling food-grade DE requires caution. The primary risk is inhalation, which can irritate the lungs and nasal passages. To minimize this risk, always wear a dust mask and gloves when handling the powder.
To consume food-grade DE, it must be mixed with water or another liquid immediately before drinking, as it does not dissolve. Individual use may vary, and there is no scientifically established safe consumption amount for supplementation.
Before adding any new supplement to your diet, especially if you are pregnant, breastfeeding, or have pre-existing health conditions, it is essential to consult a healthcare professional.
Beyond Nutrition: Other Uses of Food Grade DE
While its use as a dietary supplement is popular, food-grade DE is also widely used for other safe, organic purposes due to its non-toxic, abrasive properties:
- Natural Pest Control: It works mechanically against crawling insects like bed bugs, fleas, and ants. The microscopic, sharp edges damage the pests' exoskeletons, causing them to dehydrate and die.
- Animal Feed Additive: In farming, it is added to animal feed as an anti-caking agent and to control internal parasites, though scientific evidence for the latter is limited.
- Deodorizer: Its absorbent qualities make it an effective natural deodorizer in refrigerators, trash cans, and other areas.
- Cleaning Agent: Its mild abrasive texture makes it suitable for use in certain household cleaning applications.
Conclusion
Identifying which DE is food grade is the most critical step before considering it for dietary use. Always confirm that a product is labeled as "Food Grade" and contains less than 1% crystalline silica, as industrial filter grades are highly toxic if inhaled. While anecdotal evidence points to a range of health benefits related to digestion, detoxification, and mineral intake, concrete scientific research remains sparse. Given the limited data, and the potential respiratory risks associated with handling the dust, food-grade DE should be approached with caution as a dietary supplement. Consult a healthcare provider for professional advice before incorporating it into your diet. For additional safety information regarding diatomaceous earth as a pesticide, you can refer to the National Pesticide Information Center guidelines.
