Rarely, exceptional technological circumstances may justify the use of an additive. One further food additive was accepted for infant formulae, two for follow-on formulae and one for weaning foods. Biological differences between infants on the one side and children and adults on the other which may increase susceptibility of infants to chemical insults compared to other segments of the population. No systematic research has been performed to address this issue, but information to assess this question is scattered throughout the scientific literature. Basically infants are in a progressive stage of development and growth.
Infants do have a higher metabolic rate than children and adults.
The relative weight gain during the first 6 months of life is higher than during any other period in life. In the new born infant, gastric pH is relatively high and only reaches acidity at several months of age. This means that the ionisation state of chemicals in the gastrointestinal tract and consequently the possibility for passage of chemicals into the body will be different in the infant compared with older children. The volume of distribution for the chemical in a premature infant may be twice as large as than of an adult. The infant only reaches adult levels of most enzyme systems by 2-3 months of age.