Evaluation of growth and early infant feeding: a challenge for scientists, industry and regulatory bodies.

Growth studies are necessary to prove safety and efficacy of new or renovated infant formulas. Healthy infants need to be followed in randomized clinical trials until 4-6 months of age. Breastfed reference groups should be included in such studies, because growth of formula-fed infants may deviate from breastfed infants. The WHO growth standard describes growth of exclusively or predominantly breastfed infants and is frequently used as reference. However, the limitations of the standard must be known because weight-for-age until 6 months is higher than in all international growth references. Meta-analyses indicate that both weight and BMI of breastfed reference groups in clinical trials and of infants fed a low protein formula are somehow lower than the WHO standard. Infants of overweight and obese mothers or at risk for malnutrition are considered as at-risk populations. Any infant formula trial in those populations should use the WHO standard to document safety.