The ADI (Acceptable Daily Intake) or DGA (acceptable daily intake) establishes the amount of a given substance that a person can take every day, for life, without consequences for health. This quantity is expressed in milligrams of product per kg of body weight. Adults, therefore, can be understood to tolerate certain substances better than children.
How is the ADI value established?
The acceptable daily intake of a food additive is proposed by the producer on the basis of experiments carried out on animals, and verified by a control office. With the administration of food to rodents, the maximum degree of toxicity is first established. The latter is measured taking into account the amount of substance that causes the death of 50% of the guinea pigs. This dose is called DL (50% lethal dose).
In the following 90 days a test is carried out to determine sub-chronic toxicity (incomplete toxicity). Finally, another 2 years of research are needed to establish chronic toxicity (toxicity that occurs slowly, over a longer period of time). Finally, the amount of additive is provided which has not caused damage of any kind on guinea pigs. The concentration that on guinea pigs has proved to be harmless is expressed in milligrams of additive per kg of feed. This value is converted based on the harmless dose administered to the individual guinea pig, and expressed in daily milligrams of additive per kg of body weight.
Since the ADI value must be valid for people, the harmless dose administered to the guinea pig is divided by 100. This factor 100 is composed of a factor 10, which takes into account the risks of transmission on humans, multiplied by a second factor 10, considered as a safety factor.
For example, the ADI value for SODIUM NITRATE is 0.1 milligrams. This means that an adult of 70 kg can take up to 7 milligrams (70x0.1 mg) of sodium nitrate daily, without this causing damage to health; consequently it can be guessed that the dose that can be taken safely varies with the weight of the person being examined.
Scientists around the world are currently examining the ADI factor and discussing new principles that better assess health risk.
Even if the concept of ADI is critically evaluated, its values represent the only scientific basis currently present, and the estimation of risks can only be carried out with the help of this concept. As long as the alternatives discussed are not internationally recognized, the method currently in use must be used. However, there are new toxicological approaches that flow into future risk assessment programs.
Some research shows that for most of the additives used today it is not necessary to fear the overcoming of the currently accepted daily doses, even in the case in which certain foods with additives are consumed in an above-average way. However, according to some scientists, exceeding the ADI values involves risks (this is particularly true for groups of people with special eating habits and in specific physiological situations such as pregnancy).
- The additive MUST NOT REACT with the food or one of its constituents originating one or more toxic compounds. Among the different examples that can be included, they stand out in particular:
- Nitrite, as it is or formed from the added nitrate, in the presence of secondary amines, can originate N-alkyl-nitrosamines, powerful carcinogens. Caution is therefore required when using these additives, hoping to find more satisfactory substitutes;
- The AGENE process, treatment of flours with nitrogen trichloride, was abandoned when it occurred that it reacted in particular with gluten methionine, giving rise to a toxic sulfimine;
- Sulfur dioxide breaks down thiamine (vitamin B1): therefore its use is banned from foods that are a dietary source of this vitamin
- Diethylpyrocarbonate, a powerful antiseptic, under certain conditions, before being broken down into its constituents (ethyl alcohol and carbon dioxide), can react, for example in wines, with ammoniacal nitrogen and originate urethanes, carcinogens. For this reason the use of the compound has been abandoned in oenology;
- The additive MUST NOT MASK food alterations. For this reason, sulphite has been banned from use, especially in minced meat, where it has been replaced by ascorbic acid or better by scrupulous hygienic standards which also include storage at low temperatures, and possibly vacuum packed;
- The additive MUST NOT MASK commercial fraud;
- The additive MUST MEET A defined PURITY STANDARD, especially as regards residues and impurities in processing, and toxic metal traces;
- Of the additive analytical methods MUST BE AVAILABLE, as far as possible simple, suitable for the recognition and quantitative determination in all foods for which their use is permitted.
- All permitted additives must appear in POSITIVE LISTS, by the Health Administration. Positive lists must be constantly updated, in relation to continuing toxicological research.
