Acceptable daily intake

History

This concept was first introduced in 1961 by the Council of Europe and later, the Joint FAO/WHO Expert Committee on Food Additives (JECFA), a committee maintained by two United Nations bodies: the Food and Agriculture Organization (FAO) and the World Health Organization (WHO).

Concept

An ADI value is based on current research, with long-term studies on animals and observations of humans. First, a no-observed-adverse-effect level (NOAEL), the amount of a substance that shows no toxic effects, is determined. Usually the studies are performed with several doses including high doses. In the case of several studies on different effects, the lowest NOAEL is usually taken. Then, the NOAEL (or another point of departure such as a benchmark dose level (BMDL)) is divided by a safety factor, conventionally 100, to account for the differences between test animals and humans (factor of 10) and possible differences in sensitivity between humans (another factor of 10).

The ADI is considered a safe intake level for a healthy adult of normal weight who consumes an average daily amount of the substance in question. Increased safety factors for infants have been discussed, but are not needed, because elimination of chemicals is in fact often more rapid in children and as children generally have higher illness rates than adults, adverse effects caused by food additives can easily be disguised as any number of things children usually experience. It would be far more difficult to argue the case with a healthy adult. The ADI does not take into account allergic reactions that are individual responses rather than dose-dependent phenomena.

The higher the ADI, the larger amounts of a compound are safe for regular ingestion. The concept of tolerable daily intake is often used for unwanted contaminants or other chemicals.

The ADI concept can be understood as a measure to indicate the toxicity from long-term exposure to repeated ingestion of chemical compounds in foods (present and/or added), as opposed to acute toxicity.

The threshold limit value (TLV) of a chemical substance is a level to which it is believed a worker can be exposed day after day for a working lifetime without adverse effects.

Notes

References

1. WHO. (1987). "Principles for the safety assessment of food additives and contaminants in food". Environmental Health Criteria 70..
2. Lu, Frank C.. (2002). "Lu's Basic Toxicology: Fundamentals, Target Organs and Risk Assessment". Taylor & Francis.
3. (2001). "Casarett & Doull's Toxicology: The Basic Science of Poisons". McGraw-Hill.
4. Fennema, Owen R.. (1996). "Food chemistry". Marcel Dekker.
5. (1998). "Toxicokinetics in infants and children in relation to the ADI and TDI". Food Additives and Contaminants.