Silicon Dioxide in Food

Why is silicon dioxide in food? Studies have revealed that silicon (element) is found naturally in foods in the form of silicon dioxide (SiO₂). Silicon is never present in its original or free form, and hence, it commonly occurs as silicon dioxide (silica). Silicon dioxide is found in higher amounts in plant-based foods. The SiO₂ content is remarkably high in cereals. On the other hand, the concentration of SiO₂ is comparatively less in foods that are derived from animal sources.

Silicon Dioxide in Food
Silicon is an indispensable part of the food that we eat daily. It is observed that silicon plays a significant role in the development of the bones, so it becomes necessary to include silicon food sources in our diet. In order to maintain healthy strong bones and joints, silicon dioxide in foods is very much essential. Along with calcium and vitamins, silicon dioxide is equally important for proper bone growth, strength and density. Deficiency of silicon can cause osteoarthritis and arthritis. Another important health benefit of silicon is that it minimizes aluminum effects on the body, thereby preventing Alzheimer's disease. Some of the foods that contain silicon are as follows:

Fruits: Fruits also contain a good amount of silicon dioxide. Silicon naturally occurs in fruits so this can be an added advantage for eating fruits. Following are the fruits that are considered to be high in silicon:

• Oranges
• Apples
• Plum
• Cherries
• Grapes
• Raisins

Vegetables: Vegetables are a great source of silicon, especially the green vegetables (beans and peas) are known to contain high amount of silicon. One can enhance silicon intake by consuming the following vegetables:

• Cucumber
• Celery
• Raw cabbage

Nuts: Nuts have traditionally been a great source of minerals. Nuts, particularly the peanuts and almonds have a considerable amount of silicon in them.

Whole Grains: An easy way to prevent silicon deficiency is to include whole grain breads in the diet. Rice, barley and oats are high in silicon content. Raw oats too can contribute to silicon intake considerably.

Drinking Water: Silicon dioxide also occurs in drinking water in the form of silicic acid. Although water purification techniques have been developed to extract silicon from the water, they are not yet implemented considering the numerous health benefits of silicon. Surprisingly, silicon dioxide levels vary depending on the type of water. It has been found that soft water is a poor source of SiO₂, whereas hard water is rich in this mineral.

Silicon Dioxide Uses
Silicon dioxide is abundantly found in the Earth's crust. Sand or quartz are the two most common forms of silica. SiO₂ has a myriad of uses, making it one of the most important mineral for humans. Some of them are listed below:

Electronics: The thriving electronics industry uses SiO₂ for manufacturing fiber optic cables, wire insulation and semi-conductors. As it has a high melting point, it is often used to insulate wires.

Piezoelectric: SiO₂ (quartz) displays piezoelectric properties, which means it can convert mechanical energy to electrical energy and vice-versa. Radio and TV stations use this property of silica in order to transmit and receive signals in a proper manner.

Glass: The industrial process required for the production of domestic glass to make windows, jars and bottles, use silica. When SiO₂ is mixed with soda and boron oxide, the resultant mixture forms a glass which is resistant to thermal shock. This glass is often used for cooking as it provides high thermal stability.

Cement: One of the important uses of silica is in the manufacture of Portland cement. This type of cement is commonly used around the world. Portland cement is basically a fine powder and an important constituent of concrete.

Refractory Materials: Silica sand is very useful for manufacturing refractory materials. The reaction of Bayer alumina with silica sand gives rise to synthetic mullite refractory bricks. Silica sand when reacted with coke forms a refractory material known as silicon carbide that has high shock resistant properties.

Silicon Dioxide Food Additive
SiO₂ is an important food additive in powdered foods. Silica is also added in nutritional health food supplements and is an important constituent of many pharmaceutical drug tablets. SiO₂ is also used as a food additive in many processed foods. Many ask - why is silicon dioxide in food added externally? This is because the food additive SiO₂ also functions as an anti-caking agent (an additive when added to a mixture, prevents its ingredients from binding together). Common salt has an anti-caking agent which does not allow the ingredients of the salt to clump (stick) together. The spices sprinkled on the chips (snacks) also contain silicon dioxide which helps to enhance taste.

Silicon Dioxide in Food Safety
Silicon dioxide food safety is of prime concern especially when it is used as an additive. SiO₂, added as an anti-caking agent to a food product is not safe when the SiO₂ quantity is more than 2 percent of the food's weight. More specifically, for SiO₂ to be safe, it should be made by a process known as vapor phase hydrolysis. If it is manufactured by any other process, then the recommended particle size of SiO₂ should not exceed the safety norms. Supplements having over 2 percent of silicon dioxide are also not considered to be safe for consumption.

Silicon dioxide when added externally to food in the right amount, can produce the intended effects, otherwise it may lead to severe health problems. On the whole, dietary silica has gained an important status in the diet as it is known to maintain bone growth.