Breastfeeding Duration and Weaning Diet May Shape Child’s Body Composition

Variations in both milk feeding and in the weaning diet are linked to differences in growth and development, and they have independent influences on body composition in early childhood, according to a new study accepted for publication in The Endocrine Society’s Journal of Clinical Endocrinology & Metabolism (JCEM).

Previous studies suggest that the early environment may be a significant factor in childhood obesity. This study used dual x-ray absorptiometry to make direct measures of body composition in children at four years of age whose diets had been assessed when they were infants. The findings showed that children who had been breastfed longer had a lower fat mass which could not be explained by differences in family background or the child’s height.

“Most studies linking infant feeding to later body composition focus on differences in milk feeding, but our study also considered the influence of the weaning diet,” said Dr. Siân Robinson, PhD, of the MRC Epidemiology Resource Centre, University of Southampton in the United Kingdom and lead author of the study. “We found that, independent of the duration of breastfeeding, children with higher quality weaning diets including fruits, vegetables, and home-prepared foods had a greater lean mass at four years of age.”

In this study, researchers assessed the diets of 536 children at six and 12 months of age. Diet was assessed using a food frequency questionnaire that was administered by trained research nurses to record the average frequency of consumption of specific foods. The age at which solid foods were introduced into the infant’s diet was also recorded. In this study ‘weaning’ is defined as the period of transition in infancy between a diet based on milk feeding to one based on solid foods. The subjects’ body composition was assessed at four years by dual X-ray absorptiometry.

“These findings are enlightening,” said Professor Cyrus Cooper, Director of the MRC Epidemiology Resource Centre. “An influence of qualitative differences in the weaning diet on childhood body composition had not been described before.”

Other researchers working on the study include Lynne Marriott, Sarah Crozier, Nick Harvey, Catharine Gale, Hazel Inskip, Janis Baird, Keith Godfrey, and Cyrus Cooper of the University of Southampton in the United Kingdom and Catherine Law of University College London in the United Kingdom. The study was funded by the UK Medical Research Council, University of Southampton, British Heart Foundation and the Food Standards Agency.

The article “Variations in infant feeding practice are associated with body composition in childhood: a prospective cohort study,” will appear in the August 2009 issue of JCEM.

Founded in 1916, The Endocrine Society is the world’s oldest, largest and most active organization devoted to research on hormones and the clinical practice of endocrinology. Today, The Endocrine Society’s membership consists of over 14,000 scientists, physicians, educators, nurses and students in more than 100 countries. Society members represent all basic, applied, and clinical interests in endocrinology. The Endocrine Society is based in Chevy Chase, Maryland. To learn more about the Society and the field of endocrinology, visit our site at www.endo-society.org.