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Biomarkers, Toxicokinetics and Default Safety Factors


This research project aims to assess whether current default safety factors which are used in the risk assessment of food additives are sufficient to protect the consumer.

<p>Default uncertainty (safety) factors are used in the risk assessment of chemicals, including food additives.
Uncertainty factors are used to extrapolate from a No Observed Adverse Effect Level (NOAEL) in the animal test species to a safe intake for humans, known as the Acceptable Daily Intake (ADI).
A 100-fold factor has been used historically to convert the NOAEL into an ADI.

<p>This project aims to determine the kinetic parameters for six food additives following oral dosing in humans and animals.
This will help to assess the adequacy of the inter-species and inter-individual toxicokinetic default factors.

More information

In vivo studies will be carried out in humans and animals, which will involve administering single doses of the food additives (thiabendazole, butylated hydroxytoluene, curcumin, and three gallate esters) at the NOAEL and at ten times less than the NOAEL in animals, and at the ADI and at ten times greater than the ADI, in humans.

<p>Plasma and saliva from human volunteers will be analysed to determine the concentration of additive present. In vitro studies will also be carried out using human and animal liver preparations, with the food additives.

<p>One of the initial aims of this project was to investigate the kinetics of the same food additives in potentially vulnerable groups such as children, pregnant women and the elderly, using salivary concentrations as a non-invasive biomarker.
The concentrations in saliva would then have been compared with plasma from healthy adults in the study. This was however not possible because extremely low concentrations of the food additives were detected in human plasma despite the use of sensitive analytical methods.
Because the concentrations of compounds in the saliva would usually be similar to or less than the concentration in plasma, salivary concentrations would probably not be detectable and would therefore not provide reliable estimates of the kinetics of these compounds in groups such as children, pregnant women and the elderly.

<p>Find more about this project and other FSA food safety-related projects at the <a href="; target="_blank">Food Standards Agency Research webpage</a>.

University of Southampton
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