Silica: what is it and why is it good for your bones?

Everything has its right context. Thumping music is great at a concert venue, but not so welcome when it’s coming through your wall from the neighbor’s apartment.

Hot chicken noodle soup is one of the most comforting foods out there—but you probably won’t be happy to see it served up in the summer. Silica is the same way, which is why it has a reputation that makes people uneasy.

Silicon dioxide, also known as silica, is a combination of silicon and oxygen. This trace mineral is found in a wide variety of places on earth. It’s found in plants, rocks, drinking water, animals, sand, and our bodies. No recommended dietary allowance (RDA) is established for this element, but there’s some evidence that it’s beneficial for health. Overall, though, information about the role of silicon in the body is extremely limited.

You might have heard negative things about silicon dioxide in the past. That’s largely due to news about silicosis, a fatal lung disease caused by the inhalation of silica. Exposure to silica in the air and this disease occur mostly in people with jobs such as mining, sandblasting, quarrying, construction, and steelwork.

But ingesting silicon dioxide is very different from breathing it, and research from the World Health Organization shows that very little of the silica we eat or drink stays in our bodies. Most of it is flushed regularly by our kidneys.

Silicon dioxide is also used in processed foods as an anti-caking agent so that any moisture that gets in doesn’t cause clumping. The U.S. Food and Drug Administration FDA did evaluate the safety of silica used as a food additive and deemed it safe (FDA, 2019).

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Silicon dioxide may help build strong bones. Bone health is a little more complicated than how we generally talk about it. We don’t just form healthy bones and then, hopefully, maintain the same bone strength.

Our bones go through a complicated process of growth, modeling or consolidation, and remodeling—the latter of which happens throughout our lives. So just because bone formation happened and your bones are healthy and strong doesn’t mean they’ll stay that way.

Remodeling refers to the process that happens when bone is broken down and formed again, not always in the same way—or at the same quality. These internal supports also go through mineralization, a process in which mineral crystals are deposited in a structure.

The strength of our bones is determined by two factors: bone mineral density, how many of those mineral crystals there are in an area of bone, and bone matrix quality, which is basically everything about the bone’s structure and composition that doesn’t involve minerals.

So it’s safe to say that bone mineralization is a little important. And this process isn’t possible without collagen, which forms the foundation. Silicon dioxide may support the formation of collagen fibers, which means it may help at the most basic level of your bone health.

According to one study, silica stimulates not only collagen synthesis (which gives structure to connective tissue) but also the growth of bone cells, called osteoblasts. A retrospective study that looked at the effects of fluoride, silicon, a medication known as etidronate, and magnesium found that silicon significantly increased femoral but not vertebral BMD (Reffitt, 2003).

But silicon dioxide may also help keep your bones strong and may potentially prevent bone loss. Silica may inhibit the production of cells that break down your bones called osteoclasts as well as bone resorption (Mladenovic, 2014).

Some breaking down of your bones is normal because it’s an important part of bone remodeling. But certain diseases affect the rate at which bones are broken down, such as osteoporosis, and can lead to bone weakening and increased fracture risk.

In fact, one study found that higher silica intake (around 40 mg a day) was associated with 10% higher bone density than lower, 14 mg doses. Bone mineral density increased specifically in the cortical bone, the dense outer bone, in the hips of men and premenopausal women at the higher doses—but not postmenopausal women (Jugdaohsingh, 2003). 

Another study found that silica can also benefit the spongy interior bone tissue, called trabecular bone, as well. Although human research on silica supplementation, osteoporosis, and osteopenia needs to be done, animal models show that silicon dioxide may help prevent these diseases.

There may be other health benefits of silica, but there currently isn’t enough research to prove they hold true in general populations. Silicon dioxide may, for example, help with gastrointestinal disorders such as IBS and GERD, but the work that has been done was just a pilot clinical study, and no control group was used (Uehleke, 2011).

You’re probably already consuming a fair number of natural sources of silicon dioxide because, as we mentioned, it’s in so many things on earth.

You can boost your dietary intake of this bone-building mineral with food sources that are also a basic part of a healthy diet such as leafy greens, whole grains, green beans, and—get this—beer and red wine. Beer is an excellent source of silicon dioxide because two of its primary components, barley, and hops, are rich in the mineral.

But high-bran cereal is likely your best bet for boosting dietary silicon intake, with its high silicon content of 10.17 mg per 100 g serving (Price, 2013).

Taking a silica supplement is another possible option. There’s no RDA set for silicon dioxide, and as a supplement, it’s not regulated by the FDA. That means you should always buy from a brand you can trust and ask a healthcare professional about dosage if you have questions, though past research has shown the most benefit at doses around or above 40 mg per day. The absorption of silicon is one consideration when choosing a supplement. You may also find silica in collagen supplements.

Silica is generally regarded as safe, but it does matter how you get it. As we noted earlier, ingested silicon dioxide in food or water is safe, but silica particles in the air can be dangerous. Relying on food sources is always a good route when possible, especially since it tends to be the most bioavailable form.

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Every article on Health Guide goes through rigorous fact-checking by our team of medical reviewers. Our reviewers are trained medical professionals who ensure each article contains the most up-to-date information, and that medical details have been correctly interpreted by the writer.

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Current version

January 15, 2020

Written by

Linnea Zielinski

Fact checked by

Mike Bohl, MD, MPH, ALM

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About the medical reviewer

Mike Bohl, MD, MPH, ALM

Dr. Mike is a licensed physician and a former Director, Medical Content & Education at Ro.