Study Review – “Fructose in Breast Milk is Positively Associated with Infant Body Composition at 6 Months of Age”

A recent study published in Nutrients asserts that fructose in breast milk is significantly associated with infant body composition.  Twenty-five mother-infant dyads participated in the study in which infants were exclusively breastfeed from 1 month (first time point) until 6 months (second time point). At both the 1 month an 6 month time points, expressed milk from a single breast was collected and analyzed for insulin, glucose, fructose, and lactose concentration while the infants underwent anthropometric measurements and a whole-body dual energy X-ray absorptiometry (DXA) scan to determine infant weight, length, weigh-for-length z-score, fat mass, lean mass, bone mineral density (BMD), bone mineral content (BMC), and overall percent adiposity.

Researchers noted the following results:

  • Breast milk concentrations of glucose, fructose, and lactose did not differ at 1 month versus at 6 months.
  • Fructose was present in breast milk at very small amounts (7 μg/mL).
  • After adjusting for baseline weight, sex, and maternal BMI, breast milk fructose was associated with increased weight, lean mass, fat mass, and bone mineral content.

o   Each 1 μg/mL increase in fructose was associated with a 257g increase in body weight, 170g increase in lean mass, 141g increase in fat mass, and 5g increase in bone mineral content.

  • Length was not significantly different but weight was, contributing to a higher weight-for-length z score.
  • Infant growth was not related to mother’s pre-pregnancy BMI or to any other breast milk components.

Researchers conclude “this study suggests a novel mechanism by which infants may be inadvertently exposed to fructose through breast milk, before sugar-sweetened beverages and other fructose-containing foods are introduced to the infant diet. This work also opens the door for interventions aimed towards decreased consumption of added sugars while lactating. Future work should be performed with large samples with longer follow-up (> 6 months) in order to establish whether the relationships observed between fructose exposure and infant growth meaningfully impact the development of obesity phenotypes in later childhood and to investigative mechanisms of such an effect at very low levels of fructose.”