Stable Isotope Technique to Assess Human Milk Intake in Infants Living in Contaminated Areas

The World Health Organization (WHO) recommends that infants should be exclusively breastfed for the first six months of life, followed by the introduction of appropriate complementary foods and continued breastfeeding for up to two years to achieve optimal growth, development and health. Paediatricians and policy makers agree that protection, promotion and support of breastfeeding are a public health priority. WHO classifies exclusively breastfed infants as receiving human milk and nothing else. Predominantly breastfed infants receive human milk and small amounts of other fluids (teas, water or juice) on at least three days a week. Many infants are predominantly breastfed until 9 months of age, especially in developing countries. Human milk is used in human biomonitoring as an indicator for accumulation of environmental chemicals. Evidence about toxic and potentially toxic chemicals in human milk can be used to promote environmental protection issues, but this can have an adverse effect on the public health messages issued by WHO. Breastfeeding is safer and cheaper than formula feeding and has significant advantages for the mother and her baby. Breastfed infants score significantly higher than formula-fed infants in studies of mental development. In addition, breastfeeding improves the bonding between mother and baby and has positive effects on the baby’s immune function including fewer incidents of gastrointestinal infections. There is currently no information available on the effect of environmental contamination from mining activities and natural sources on lactation performance of women living in contaminated areas. Young infants are particularly vulnerable since human milk is their primary or sole source of nutrition. Human milk intake and thus lactation performance can be accurately assessed using stable isotope technique. The CRP will use a longitudinal study design to focus on assessing human milk intake and lactation performance of nursing mothers using the deuterium oxide dose-to-mother technique. Repeated measures will be performed in infants aged 3, 6 and 9 months. Depending on the study location, the infants’ intake of lead (Pb), mercury (Hg), arsenic (As), cadmium (Cd), selenium (Se) and manganese (Mn) though human milk will be assessed by combining accurate data on human milk intake with measures of concentration. The infants’ growth will be monitored with reference to the new WHO growth standards and they will be monitored for incidence of infectious diseases.
The overall objective of the proposed CRP is to assess lactation performance of women living in contaminated areas and to provide better estimates of transfer of toxic and potentially toxic elements from mother to child via human milk.
The results generated within this CRP will contribute new data towards the evidence base supporting public health messages regarding breastfeeding.