Acceptable daily intake

Acceptable Daily Intake or ADI is a measure of the amount of a specific substance (usually a food additive, or a residue of a veterinary drug or pesticide) in food or drinking water that can be ingested (orally) over a lifetime without an appreciable health risk. ADIs are expressed by body mass, usually in milligrams (of the substance) per kilograms of body mass per day.

This concept was first introduced in 1957 by the Council of Europe and later the Joint Expert Committee on Food Additives (JECFA), a committee maintained by two United Nations bodies: the Food and Agriculture Organization FAO and the WHO World Health Organization.

An ADI value is based on current research, with long-term studies on animals and observations of humans. First, a No Observable (Adverse) Effect Level, the amount of a substance that shows no toxic effects, is determined on the basis of studies intended to measure an effect at several doses. Usually the studies are performed with several doses including high doses. In the case of several studies on different effects, the lowest NO(A)EL is usually taken. Then, the NOEL (or NOAEL) is scaled 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 usually given in mg per kg body weight per day. Note that the ADI is considered a safe intake level for the healthy adult of normal weight who consumes an average daily amount of the substance in question.

The higher the ADI, the "safer" a compound is for regular ingestion.

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.