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What Is Silicon Dioxide and Is It Safe?

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Silicon dioxide - Dr. Axe

In order to improve the texture and shelf life of granular and powdered food products, such as protein powders and seasonings, anti-caking additives are often used. One such additive is silicon dioxide, which the ability to help prevent ingredients from becoming moist and clumping together.

What is silicon dioxide exactly, and is it safe? Also known as silica, this compound exists in nature in the form of certain minerals and is also man-made in labs to be used in foods, supplements and cosmetics.

The type found in our food supply has been shown to be safe in studies, however ongoing exposure to certain types of silicon dioxide can pose a risk to people who work in mining, construction and steel industries.

What Is Silicon Dioxide? Where Is It Found Naturally?

Silicon dioxide is a compound that’s naturally found in the earth’s crust in a crystalline state. It can be obtained from mining and purifying quart.

It is also found in some organisms and animals, the human body (it’s a component of human ligaments, cartilage and musculature), plus some plants (especially grains) and in drinking water.

Additionally, it’s created in labs and used as a common food additive, found in things like baking ingredients, protein powders and dried spices. This compound has a variety of uses in industries ranging from food and cosmetics to construction and electronics.

What is silicon dioxide made of? It’s composed of a combination of silicon (Si) and oxygen (O), which is why it has the chemical formula SiO2.

What is silica, and how is it different?

Silicon dioxide goes by the common name silica. It’s also sometimes referred to as silicic anhydride or silicate.

Silica/silicon dioxide comes in several forms, depending on how it’s manufactured, including:

  • Crystalline silica, which is usually obtained from mining quartz. Quartz actually comprises a high percentage of the Earth’s crust, so this type is widely available. This isn’t the form used in foods and can be problematic when inhaled over long periods of time.
  • Amorphous silica, found in the earth’s sediments and rocks. This also forms diatomite, diatom silica or diatomaceous earth, which is made from deposits that accumulate over time in the sediment of rivers, streams, lakes and oceans.. This is the type most often used as an anti-caking agent to keep powdered foods free-flowing and to prevent moisture absorption.
  • Colloidal silicon dioxide, which is used in tablet-making. This type is found in supplements because it has anti-caking, adsorbent, disintegrant and glidant effects.

Why Is It Used in Food and Supplements?

Synthetic amorphous silicon dioxide is the type most often used as a food additive. It’s typically manufactured by vapor phase hydrolysis.

Which foods contain silicon dioxide? You’ll find it in small amounts added to foods, such as:

  • flours
  • protein powders
  • baking powder
  • confectioner’s sugar
  • salt
  • spice, herb and seasoning mixtures
  • beer (it is removed from the beer by filtration prior to final processing)
  • dried egg products
  • animal/livestock feed
  • supplement capsules

Silicates are also present in a variety of plant foods included in the human diet, including vegetables and cereal grains, such as leafy greens, peppers, beets, sprouts, rice and oats.

Because it has the ability to block moisture absorption and prevent ingredients from clumping/caking together, silicon dioxide is used in food products to help retain their texture. It’s most often found in granular or powder products, because as the U.S. Food and Drug Administration (FDA) describes it, “it increases speed of dispersion, keeping the food particles separated and permitting the water to wet them individually instead of forming lumps.”

What is silicon dioxide used for in foods and supplements? According to the USDA, silicon dioxide has properties that give it the following functions in foods and supplements:

  • Works as an anti-caking agent
  • Prevents corrosion
  • Defoams
  • Stops powders from absorbing moisture
  • Helps to stabilize and clarify beer
  • Helps carry and distribute flavoring oils
  • Absorbs alcohol
  • Helps in processing of wine and gelatin production

Depending on silicon dioxide’s structure, it can appear as a transparent, tasteless, crystal or an amorphous powder (sometimes called silica powder).

Amorphous silica has a “highly unique physical and chemical properties and potential as an additive in a variety of processing industries,” as described the USDA. For example, it has a small particle size, high specific surface area, and gelling and thickening abilities.

Something else that makes silica unique is its solubility. Silicon dioxide is not soluble in either water or organic solvents.

In addition to being used in foods supplements and cosmetics, silica is utilized in the production of cans, impermeable films, paints, silicone rubbers, polyester compounds, dental formulations, emulsions, dry pesticides, soil conditioners and turf soil.

The production of silicon dioxide is one form of “nanotechnology,” which encompasses taking a material and making it into very tiny particles, with dimensions between one and 100 nanometers. This changes the material’s physical, chemical and biological properties and functions.

While nanotechnology in food processing may help improve the taste, color, look, uniformity and texture of foods, it might also change the material is absorbed and excreted in the human body.

Is It Safe? Risks and Side Effects

Is silicon dioxide safe to consume? The FDA considers silicon dioxide in food to be generally safe for human consumption, as long as it’s consumed in small amounts.

Is silicon dioxide a carcinogen? There isn’t evidence that the type used in foods contributes to cancer formation. The Environmental Protection Agency has stated that crystalline-free form of silica poses “minimal risk” to humans.

While they are rare, silicon dioxide side effects are possible. This can include symptoms of allergic reactions and possibly digestive problems.

One potential concern with nanoparticles found in foods (which includes silicon dioxide in addition to compounds like silver, titanium dioxide, iron oxide and zinc oxide) is that some research suggests they may trigger GI problems, such as leaky gut syndrome, as well as DNA and cell damage when ingested long term. More research is needed regarding these concerns, because as of now we don’t know much about the long-term impacts of eating nanoparticles on a regular basis.

Here’s another distinction to point out: The type of silica found in foods is different than crystalline silica, which is a component of soil, sand, granite and some other mineral. Long-term exposure to crystalline silica can potentially be dangerous to the respiratory system, contributing to lung-related damage and disease, so anyone who works in close contact with this compound needs to be careful to handle it properly in order to prevent side effects.

People who are most susceptible to experiencing side effects due to crystalline silica exposure are those who work in the following industries: mining, steel, construction and sandblasting.

Any Benefits? (Plus RDA/Limits)

Are there any known benefits of silica/silicon obtained from foods? Overall, when consumed as a food additive it seems to be mostly neutral, providing little benefit, other than making foods have a better texture and shelf life.

One reason is because silicon dioxide (SiO2), in the food additive form, has limited intestinal absorption.

That said, related products like diatomaceous earth that provide more concentrated amounts of silica do seem to offer benefits.

Certain studies have shown that silicon is an essential mineral for the body and helps build strong bones, hair, nails and teeth. It may have anti-aging effects and help prevent symptoms tied to deficiencies in silicon, such as:

  • abnormal growth
  • weak bones
  • deformities in skull and peripheral bones
  • joint pain
  • poor mineral balance

According to a study published in the International Journal of Endocrinology, silicon has been shown to support bone-building and have bone-protecting properties, plus it may play a role in collagen formation. Some research suggests silicon can help improve bone density and bone flexibility and protect the teeth.

How much is safe to consume, according to available research?

The best way to obtain natural silicon is through eating healthy plant foods and herbs. These foods include:

  • whole grains like oats and rice
  • leafy greens
  • green beans
  • melons
  • cucumbers
  • artichokes
  • asparagus
  • dandelion
  • beer
  • herbs like nettle leaf, horsetail, oat straw and rosehip (these herbs may be consumed in supplement and tea form, too)

There’s some evidence that getting about 40 milligrams daily of silicon from your diet may be linked with stronger bones.

The FDA has stated that silica added to food can not exceed 2 percent of the food’s total weight. The Expert Group on Vitamins and Minerals set a safe upper level for daily consumption of silicon at 12 milligrams per kg body weight/day (for a 60 kg adult).

It isn’t necessarily dangerous to consume silica in higher amounts than what is typical, but research is lacking to prove just how much is safe.

Wondering if silicon dioxide in foods is vegan?

Most often, yes. That’s because it’s usually man-made in a lab.

Conclusion

  • What is silicon dioxide? It’s a compound found naturally in the Earth’s surface, in the human body and in some animals, plus in plants and drinking water.
  • It’s also man-made and most often used as an anti-caking agent to keep powdered foods free-flowing and prevent moisture absorption.
  • You’ll find this food additive in foods such as baking powder, protein powder, sugar, salt and spices.
  • Is silicon dioxide safe to ingest? Experts believe that silicon dioxide side effects are rare and that consuming this food additive poses minimal risk.
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