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Silicon Dioxide (E551) — What You Need to Know

Generally Safe(8/10)Synthetic

The score is an eNumbers.org editorial summary, not an official agency rating or medical advice. Start with the regulatory status and primary sources below.

What Is Silicon Dioxide?

Silicon dioxide (silica) is a natural mineral compound and the most abundant mineral in the Earth's crust. As a food additive, it is used in powdered and granulated foods to prevent clumping by absorbing moisture. It is chemically inert and passes through the body largely unabsorbed. However, the food-grade form is an amorphous (non-crystalline) silica, distinct from crystalline silica which is a known lung hazard when inhaled as dust in occupational settings.

What Is It Used For?

Used in powdered foods, spice mixes, instant soups, table salt, powdered milk, and food supplements to prevent clumping and improve flowability. Also used as a carrier for flavors and other additives.

Function: Anti-caking agent, carrier
5 mg
Dataset exposure estimate

Exposure figures are population-level references, not personal limits. Actual intake varies by diet, product and jurisdiction.

Regulatory & Editorial Context

📊
Acceptable Daily Intake (ADI)
No ADI established — considered safe without a defined limit
🏛️
Regulatory Status
🇺🇸 USA (FDA): GRAS
🇪🇺 EU (EFSA): Authorized
⚠️ Key Concerns

Food-grade amorphous silica is considered safe by EFSA and FDA. Important distinction: crystalline silica (found in sand and rocks) is a known carcinogen when inhaled as dust in occupational settings (quarry workers, miners). Food-grade amorphous silicon dioxide poses no such risk. EFSA confirmed its safety in 2018 and found no evidence of systemic toxicity at food additive levels.

Editorial context score

eNumbers.org currently assigns Silicon Dioxide an editorial context label of Generally Safe with a score of 8/10. This is equal to the database average for anti-caking agents (8/10). Dataset reference year: 2018.

This score is not issued by EFSA, FDA, WHO or another regulator.

Commonly Found In

Table saltSpice mixesInstant soupsPowdered sugarFood supplementsCoffee whitener

Always check the label for E551 or 'Silicon Dioxide'

▶Chemical Information
Formula: SiO2
Molecular Weight: 60.09 g/mol
CAS Number: 7631-86-9
INS Number: 551
Also known as: E551, INS 551, Silica, Amorphous silica, SiO2

Frequently Asked Questions about Silicon Dioxide

Current dataset status: FDA — GRAS; EFSA/EU — Authorized. Reported concerns: Food-grade amorphous silica is considered safe by EFSA and FDA. Important distinction: crystalline silica (found in sand and rocks) is a known carcinogen when inhaled as dust in occupational settings (quarry workers, miners). Food-grade amorphous silicon dioxide poses no such risk. EFSA confirmed its safety in 2018 and found no evidence of systemic toxicity at food additive levels. Regulatory status and individual risk are not the same; check the primary sources and permitted conditions of use.

Quick Facts

E-Number
E551
INS Number
551
Category
Anti-caking Agents
Origin
Synthetic
FDA Status
GRAS
EFSA Status
Authorized
ADI
No limit
Dataset Review
2018
Ingredient-level Dietary Notes
Vegan: ✅ YesHalal: ✅ YesKosher: ✅ YesGluten-Free: ✅ Yes

Carriers, processing aids and product certification can change suitability. Verify the final label and certifier.

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Disclaimer: This information is for educational purposes only and is not medical advice. Always consult a healthcare professional for health-related decisions.