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French Agency for Food, Environmental and Occupational Health & Safety

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Updated on 21/09/2016

Total Diet Studies (TDSs)

A realistic approach for determining nutritional and health risks related to food

Keywords : Food contaminants, Food consumption surveys, TDS (Total Diet Study)

Total Diet Studies (TDSs) are carried out nationally and follow a standard methodology recommended by the World Health Organization (WHO). Their primary aim is to monitor exposure of the population to chemical substances present in food, including residues of plant protection products, environmental contaminants, neoformed compounds, natural toxins, additives, trace elements or minerals.

Introduction to total diet studies

A total diet study involves collecting samples of foodstuffs regularly consumed by the population from various points of sale, preparing them as they are consumed, and mixing them into "composite" samples to obtain a limited number of test mixtures. These mixtures are then examined to detect a certain number of toxic substances and nutrients: residues of plant health products, environmental contaminants, neoformed compounds, natural toxins, additives, trace elements or minerals, for example. The purpose of these studies is to measure the quantity of chemical substances ingested by the general population and by various specific population groups (region, age, etc.). These data are needed to evaluate the health risks for the consumer associated with chemical substances.

Since foodstuffs are analysed after preparation as in real-life conditions, i.e. washing, peeling and cooking as appropriate, this method has the advantage of providing “background noise” exposure data that are more realistic than approaches based on food standards or on results of monitoring and control programmes. In addition, these studies follow a standard methodology, recommended by the World Health Organization (WHO) for a number of years, and therefore make it easier to compare consumer exposure data between countries. 

These studies constitute an important scientific tool for decision-making at the EU and international levels concerning regulation of chemical substances, food safety, and consumer protection. Total diet studies are therefore conducted by a number of countries to provide data on nutritional and health risks.


TDSs in France

The first total diet study in France (EAT1) was carried out between 2000 and 2004 by the French National Institute for Agricultural Research (INRA), in collaboration with the French Food Safety Agency (AFSSA). It provided an overview of exposure of the population, both adults and children, to inorganic and mineral contaminants, and to mycotoxins. 

In 2006, the Agency launched an internal request to carry out a second study (EAT2), including 445 substances compared to 30 analysed in the first study. This TDS was financed by public funding from the Ministries of Agriculture, Health and Consumer Affairs, with a contribution from the French Observatory for Pesticide Residues, and results were published in June 2011. In total, the EAT2 study included collection of 20,000 food products covering 212 food types, for which 445 substances of interest were analysed.

ANSES is currently carrying out a total diet study to last from 2011 to 2014, focused specifically on infants and young children (0-3 years of age).

Finally, since 2012 ANSES has been coordinating the four-year TDS-Exposure European research project to harmonise and distribute the TDS methodology in Europe.


Substances analysed in EAT2 

All of the substances analysed in EAT1 were also assessed in EAT2 in order to monitor population exposure levels over time. A large number of other substances were added to this list in order to describe a wider range of exposures.

ANSES selected the substances to be analysed based on the following criteria: existing needs in terms of risk assessment, the need to describe changes in exposure and to better describe exposure for certain contaminants, emerging substances identified in the literature for which a risk assessment would be useful, recommendations on monitoring included in Agency opinions, and analytical capacities. Overall, 445 substances in 11 different categories were assessed:


Preliminary results of EAT2

Generally, EAT2 has confirmed the high level of risk management in France concerning the potential presence of chemical contaminants in food, on the basis of regulatory thresholds and available toxicity reference values. 

However, this study has also demonstrated that in certain population groups there is a risk that toxicological thresholds may be exceeded for some substances, such as lead, cadmium, inorganic arsenic and acrylamide, requiring efforts to reduce exposure. Since these risks are often associated with high levels of consumption of a foodstuff or group of foodstuffs, ANSES highlights the importance of a diversified, balanced diet in which the types of food and their quantities are varied. 

Finally, the study has shown that there is a need to develop scientific knowledge concerning both toxicology and analytical techniques for a range of currently non-regulated substances that are found in food, and for which the assessment of risks is currently not conclusive.