A new study by researchers at the Keck School of Medicine of USC indicates that a “secondhand sugar” – derived from a mom’s diet – is passed from mother to infant through breast milk.
Even a small amount of fructose – a sweetener linked to health issues ranging from obesity to diabetes – in breast milk is associated with increases in a baby’s body weight.
2017 Study Abstract
Fructose in Breast Milk Is Positively Associated with Infant Body Composition at 6 Months of Age, Nutrients, doi:10.3390/nu9020146, 16 February 2017.
From mother to baby: ‘Secondhand sugars’ can pass through breast milk, news.usc.edu, MARCH 2, 2017.
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Dietary sugars have been shown to promote excess adiposity among children and adults; however, no study has examined fructose in human milk and its effects on body composition during infancy.
Twenty-five mother–infant dyads attended clinical visits to the Oklahoma Health Sciences Center at 1 and 6 months of infant age. Infants were exclusively breastfed for 6 months and sugars in breast milk (i.e., fructose, glucose, lactose) were measured by Liquid chromatography-mass spectrometry (LC-MS/MS) and glucose oxidase. Infant body composition was assessed using dual-energy X-ray absorptiometry at 1 and 6 months. Multiple linear regression was used to examine associations between breast milk sugars and infant body composition at 6 months of age. Fructose, glucose, and lactose were present in breast milk and stable across visits (means = 6.7 μg/mL, 255.2 μg/mL, and 7.6 g/dL, respectively).
Despite its very low concentration, fructose was the only sugar significantly associated with infant body composition. A 1-μg/mL higher breast milk fructose was associated with a 257 g higher body weight (p = 0.02), 170 g higher lean mass (p = 0.01), 131 g higher fat mass (p = 0.05), and 5 g higher bone mineral content (p = 0.03).
Overall, 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 larger 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 the mechanism of such an effect at very low levels of fructose.
In conclusion, we provide preliminary evidence that fructose is present in breast milk and may be transmitted to the infant, impacting growth and body composition by 6 months of age.