Matthew Messer

Matthew Messer


Many people are concerned about the countless additives in our food. Although in some cases they can cause problems, many times they are perfectly safe ingredients, which are threatening in name alone. One such popular additive is silicon dioxide, or silica, which, although it is indeed harmful when inhaled as a powder, does not appear to be dangerous when ingested.

What is silicon dioxide?

Silicon is one of the most abundant elements on Earth, and silicon dioxide is its compound with oxygen, yielding none other than sand. It should not be confused with silicone, which is an artificial plastic compound.

Sand itself doesn't sound very appetizing, but it can also be found in our natural foods and is good for our health.

Although its role in the human body is less well understood, it is also necessary for healthy skin, hair and bones. Read our summary article to find out what we know about it.

Why is silicon dioxide added to food?

Silicon dioxide acts as an anti-caking agent in most foods and food supplements, as its unique structure helps to prevent different ingredients from sticking together.

Many people are concerned about the harmful effects of silica, but current evidence suggests that it is not dangerous.

What does the research tell us?

The silica in our food is completely safe, the excess is easily excreted and we don't have to worry about it causing any problems.

Foods and supplements that contain silica also do not contain the amounts that current evidence suggests would be harmful. This is why its use in food additives was approved by the European Food Safety Authority (EFSA) in 2008.

Sometimes people accidentally ingest silicone gel, taking in huge amounts of synthetic silica at once. Although this can cause choking due to its water-binding effects, it also has very low toxicity.

Even at extremely high oral doses of 9000 mg per kilogram of bodyweight per day, no lasting adverse effects have been observed, and silica has no gene-damaging or carcinogenic effects at similar mega-doses.

The average daily intake of silica is only 20-50 mg per day, while the safe upper limit of intake has been set at 1500 mg per day. Apparently, people are consuming orders of magnitude less than what could be a problem. And yet there may be some cause for concern.


Although it can be seen that silica itself is not harmful, it is possible that silica nanoparticles may well have a negative effect. A 2018 EFSA report revealed that it is not possible to determine exactly how much of the additives currently on the market contain nanoparticles, which could potentially be problematic.

It is unlikely that they will be a problem either, as the new report says: Based on the available data, there is no information to suggest that the additive silica (E 551) has any harmful effects at the levels consumed.

That being said, it is good to know that they are investigating and researching whether nanoparticles cause any problems, as well as advocating stricter controls on various additives.

  1. Scientific Opinion of the Panel on Food Additives and Nutrient Sources added to Food on calcium silicate, silicon dioxide and silicic acid gel added for nutritional purposes to food supplements following a request from the European Commission. The EFSA Journal (2009) 1132, 1–24.
  2. EFSA ANS Panel (EFSA Panel on Food Additives and Nutrient Sources added to Food), Younes, M, Aggett, P, Aguilar, F, Crebelli, R, Dusemund, B, Filipič, M, Frutos, MJ, Galtier, P, Gott, D, Gundert-Remy, U, Kuhnle, GG, Leblanc, J-C, Lillegaard, IT, Moldeus, P, Mortensen, A, Oskarsson, A, Stankovic, I, Waalkens-Berendsen, I, Woutersen, RA, Wright, M, Boon, P, Chrysafidis, D, Gürtler, R, Mosesso, P, Parent-Massin, D, Tobback, P, Kovalkovicova, N, Rincon, AM, Tard, A and Lambré, C, 2018. Scientific Opinion on the re-evaluation of silicon dioxide (E 551) as a food additive. EFSA Journal 2018;16(1):5088, 70

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