Uncertainty still remains over the safety of the nanomaterial SAS in food. Food additive E551 consists of ‘synthetic amorphous silica’ (SAS) and is applied as an anti-caking agent. It is present in products such as coffee creamer, soup and sauce powders and seasoning mixes.

Despite new research, definite conclusions cannot be drawn yet regarding health risks. However, RIVM has come up with new insights making the risk assessment more concrete and quantifiable than was possible until now. From this study it appears that health risks are a possibility from SAS being used in food.

Concentration in the liver

In this study RIVM calculated the maximum level of concentration of silica in the human liver for a lifelong intake of food products with SAS. Subsequently, this concentration level was compared to the concentration in the liver of laboratory animals where SAS caused inflammatory effects.

The estimated concentration in the human liver was found to be the same level as that for laboratory animals where effects were found. This suggests that health effects due to SAS in foods are possible.

Assumptions and uncertainties

These findings should be seen in the light of the assumptions and uncertainties necessary for assessing such a risk. For nanomaterials these uncertainties and assumptions are greater than usual due to a lack of basic knowledge. For example, there is more uncertainty regarding how to extrapolate the concentration in the liver of laboratory animals to the concentration in the human liver.

This work has been performed by order of the Netherlands Food en Consumer Product Safety Authority (NVWA). In the assessment particular use has been made of new studies by RIKILT – Wageningen UR as described in a recent scientific publication, and by the EU-project Nanogenotox.

Follow-up study

Further insight into the health risks of SAS in food is warranted considering the wide range of their application. In a follow-up study RIVM will investigate the amount of SAS particles in humans, including the liver, in collaboration with UMC Utrecht, RIKILT – Wageningen UR, and the NVWA.

SAS is considered a nanomaterial according to the EU Recommendation on a definition of a nanomaterial due to the small primary particles and large surface area.