Foods High in Silica

Medically Reviewed by Mahammad Juber, MD on November 29, 2022
3 min read

Silicon is the second-most abundant element on Earth, behind oxygen. Almost 30% of our planet’s crust is made of the stuff, so it isn’t surprising that it’s also found in food.

However, silicon is rarely found on its own. Instead, it combines with oxygen and other elements to form silicate materials, which are the largest class of rock-forming materials on Earth and compose 90% of the Earth’s crust. One such material is silica, or silicon dioxide, which is the most common component of sand.

Silica is also found naturally in some foods, and it is added to many food products and supplements. It is commonly used in the form of silicon dioxide as an anti-caking agent in foods and supplements to keep ingredients from clumping up or sticking together, and it’s sometimes added to liquids and beverages to control foaming and thickness.

A clear function of silica in the human body has not been established, but people take silicon as a supplement for some health issues, including: 

The Food and Drug Administration (FDA) recommends that you don’t consume more than 10-30 grams, or 2% of your daily food intake (500-1,500 grams), of silica per day.

Although consuming silica doesn’t appear to have negative effects, inhaling small particles of it can increase your risk of developing serious silica-related diseases, such as:

According to the United States Department of Labor, about 2.3 million people in the U.S. are exposed to silica at work. As long as you aren’t inhaling silica in its crystalline form, it appears to be safe to consume at the levels set out by the FDA.

Although silicon is a natural part of some foods and sees wide commercial application, the U.S. Food and Drug Administration has set out strict regulations around using silica as an additive.

Compelling data suggests that silica is essential for your health, but more evidence is needed to confirm this. Typical diets likely contain enough silica that can be absorbed for potential health benefits, despite negative perceptions of silicon as dangerous.

Here are seven foods high in silica:

1. Green Beans

Green beans are among the most silica-rich vegetables. One cup has about 7 milligrams of silica, which equals roughly 25% to 35% of the average American’s silica intake.

2. Bananas

As far as fruits go, bananas are one of the biggest sources of silica. A medium-sized peeled banana has 4.77 milligrams of silicon dioxide.

3. Leafy Greens

Many different types of leafy green vegetables are sources of silica. A 2-tablespoon serving of spinach contains 4.1 milligrams of silica.

4. Brown Rice

Although every kind of rice contains silica, brown rice has the highest amount. Three heaped tablespoons contains 4.51 milligrams of silica.

5. Cereal

Of the 18 foods with the highest silica content, 11 are cereal products, and those containing oats were at the top of the list. Two tablespoons of oat bran has 3.27 milligrams of silica.

6. Lentils

Lentils are protein-rich beans that are good sources of silica. Red lentils have the most silicon dioxide, with 1 tablespoon containing 1.77 milligrams.

7. Beer

Beer has more silica per portion than any other food or beverage. Silica is obtained during the brewing process through a hot mashing technique and is most present in lagers.