What is meant by Total Diet Studies (TDSs)?

What are TDSs?

TDSs aim to assess, at a national level, the health risks associated with chronic exposure of the population to chemicals found in food.

They enable estimates to be made of consumers’ actual exposure levels, considering both the presence of substances in food and the population’s dietary habits.

What method is used?

TDSs are based on a standardised method that has been advocated for many years by the Food and Agriculture Organization of the United Nations (FAO) and the World Health Organization (WHO) and, more recently, by the European Food Safety Authority (EFSA).

A TDS takes place in three main stages:

• collection of food samples from various points of sale such as supermarkets or markets, representing the population's food procurement practices and covering a wide range of foods;
• preparation of the collected samples to reflect the way in which consumers prepare foods before eating them, including cutting, cooking, etc.;
• laboratory analysis of samples to identify and quantify the chemicals found in the foods. The results of these analyses are then combined with food consumption data to estimate population exposure and assess the potential health risks.

What are TDSs used for?

TDSs are a key scientific tool for supporting decision-making at national, European and international levels.

Their findings help to better protect consumers by:

• guiding the regulation of chemicals in food;
• reinforcing food safety;
• identifying the substances for which efforts to reduce exposure are needed.

Many countries carry out this type of study to assess food-related nutritional and health risks.

How many TDSs have already been carried out in France?

Four TDSs have already been conducted in France:

• TDS1 (2001–2005)

Carried out by the National Institute for Agricultural Research in conjunction with ANSES, this study focused on the general population aged between 3 and 79 years and included 39 chemicals.

• TDS2 (2006–2011)

This covered the same age group, but the scope of the analysis was expanded to cover 445 substances.

• Infant TDS (2010–2016)

Devoted specifically to children under 3 years of age, this study examined 670 substances.

• TDS3 (2021–2028)

The first results have just been published. This new study is focusing on the population aged 3 to 79 years and more than 250 substances. Its findings are being published gradually, according to groups of substances. The first part has revealed the results for acrylamide and several trace metals: silver, cadmium, lead, aluminium and mercury.

What are the main findings of the French TDSs?

In general, both the Infant TDS (iTDS) and TDS2 confirmed that France has an effective system for controlling the health risks associated with the potential presence of chemical contaminants in food, on the basis of the regulatory thresholds and health-based guidance values available. However, these studies also demonstrated that in certain population groups there is a risk of toxicological thresholds being exceeded for some substances, such as lead, cadmium, inorganic arsenic and acrylamide, requiring efforts to reduce exposure.

According to the initial findings of TDS3, exposure to acrylamide, aluminium, cadmium, methylmercury and lead remains too high, despite a significant reduction in average contaminant levels in food and in exposure since TDS2. Since these risks often arise from high levels of consumption of a particular food or food group, ANSES underlines the importance of a diversified, balanced diet in which the types of foods, their origin and their quantities are varied.

Lastly, these TDSs have shown that there is a need to develop scientific knowledge of both toxicology and analytical techniques for a number of regulated or unregulated substances for which risk assessments are not currently conclusive.