The Food and Drug Administration’s Total Diet Study (TDS) monitors the U.S. population’s average annual dietary intake of more than 800 chemical contaminants and of certain nutrients. The chemical contaminants include radionuclides, pesticide residues, industrial chemicals, and toxic elements, either naturally occurring or resulting from human activity. The number of different kinds of foods analyzed in this long-term study has increased from 82, when it began, in 1961, to about 280 currently.
The results of the analyses, and summary reports for ranges of years, beginning with 1991, are available on the FDA website, along with other relevant information. To conduct the TDS, we:
- use national food-consumption surveys, such as those of the U.S. Department of Agriculture and the Centers for Disease Control and Prevention, to determine what foods, and what amounts of those foods, constitute the average U.S. diet.
- buy samples of the foods four times a year, in a different region of the U.S. each time (West, North Central, Northeast, or South), and prepare the foods the way consumers typically would. We also include purchases from fast-food restaurants.
- analyze the foods for levels of chemical contaminants; we also include naturally occurring chemical elements that are nutrients, such as potassium, calcium, etc., and chemical elements that can be toxic, such as arsenic and mercury.
- use the information above, to calculate the U.S. population’s estimated average annual dietary intake of the chemical contaminants and nutrients, per capita. We also estimate the intake for specific age groups, from 6 months to 70+ years, some of them by gender.
Some Design Features
- The surveys from which we derive the average U.S. diet include large numbers of foods. We made this large number more manageable for the TDS by grouping similar foods together and designating one food to represent them. We also calculate average per-capita consumption of each TDS food by combining the per-capita consumption amounts of all the survey foods it represents. These consumption amounts are available on the FDA website.
- We’re currently modernizing the TDS program; for example, updating the list of foods to be analyzed and our estimates of the amounts consumers eat of those foods, to reflect changing eating patterns in the U.S. Likewise, we periodically update the methods we use to analyze the foods.
We use the TDS in various ways; for example, along with other sources, it suggests potential areas of focus for our food-safety and nutrition programs.
If you have questions about the Total Diet Study, email TDS@fda.hhs.gov.