HMO levels in human milk linked to infant cognitive development: Abbott Study

25-Feb-2021 - Last updated on 25-Feb-2021 at 17:31 GMT

Levels of two specific human milk oligosaccharides (HMOs) are linked with measure of infant cognitive development, says a pilot study led by R&D Abbott Nutrition.

Data published in the Journal of Nutrition & Food Sciences indicated that 2´-fucosyllactose (2´-FL) and 6´-sialyllactose (6´-SL) were positively correlated with motor scores at 6 and 18 months of age.

In addition, 6´-SL levels in human milk were positively correlated with cognitive scores at 18 months of age, wrote the researchers, led by Elena Oliveros, R&D Abbott Nutrition in Granada, Spain.

The study shows correlation and not causation and the researchers noted: “Further research and full-scale clinical studies are needed to elucidate the effects of HMOs in pediatric neurodevelopment as well as the mechanism(s) of action involved and the influence of Low and High 2´-FL populations.”

HMOs

HMOs are unique carbohydrates that make up about 10% of the dry weight of mother’s milk. HMOs are not easily digested, so experts postulate that their purpose is to jump-start the infant’s microbiome by feeding beneficial bacteria.

There are about 200 different HMOs, and 2’-FL is the most abundant. As a result, it’s the most studied, and the one that is already commercially available from a number of suppliers.

While the new Abbott study is observational, data from intervention trials are published in the literature. The majority of the science to date has focused on infants, with a study published in Gut (He et al., 2016, Vol. 65, pp. 33–46) by scientists from Harvard Medical School indicating that 2’-FL could reduce the inflammatory response to pathogenic bacteria.

In addition, a 2017 paper in the Journal of Pediatric Gastroenterology and Nutrition (Puccio et al., Vol. 64, pp. 624–631) reported that infants fed formula with 2′-FL and lacto-N-neotetraose (LNnT), another HMO, had lower levels of bronchitis and required fewer antibiotics.

Results of a study published in the Journal of Nutrition in 2016 by scientists at Abbott Nutrition found that infants fed a formula with 2’-FL had levels of inflammatory cytokines similar to those observed for breast feeding, and significantly lower than those observed for infants fed a control formula containing no 2’-FL.

Study details

The Abbott study called “Role of nutrition and maternal genetics on the programming of development of fetal adipose tissue” (PREOBE Study) included overweight, obese and diabetic pregnant women and their babies compared to healthy, normal weight mothers and babies.

For the pilot study, 82 human milk samples from mothers considered overweight, obese, or normal weight, as well as those diagnosed with gestational diabetes were analyzed. The infants were assessed at 6 and 18 months of age using the Bayley Scales of Infant Development, Third Edition (BSID-III), which is divided into five domains: cognitive, language, motor, adaptive behavior and social-emotional development.

The researchers found that there were no significant differences between the different groups for 6´-SL and 2´-FL levels This showed that “2´-FL and 6´-SL levels in human milk are not influenced by pre-gestational maternal weight or gestational diabetic status”, said the researchers.

For the infants, the data indicated there was a strong trend for a positive association between 2´-FL levels and motor scores at 6 months of age, and this reached statistical significance when the researchers adjusted for maternal pre-conceptional weight.

For 6´-SL, a statistically significant positive association was observed for composite cognitive scores at 18 months of age. In addition, a no significant trend was observed for 6´-SL levels and motor skills at 18 months of age.

The researchers note that animal studies using 2´-FL or 6´-SL have shown cognitive benefits, with the 2´-FL studies showing improvements in brain functionality.

Commenting on the potential mechanism(s) of action, the researchers noted that these remain unclear, but noted it may be linked to metabolites produced by HMO utilization by the gut microbiota “that reach the brain producing structural changes responsible for enhanced cognitive skills”.

“Preclinical research showed administration of an exogenous source of sialylated compounds increased the sialic acid concentration of key areas of the brain suggesting sialic acid reached the brain; it is unlikely that intact 2′-FL goes to the brain directly but may act via the Gut-Brain Axis (GBA) and through the vagus nerve. GBA is a complex bidirectional network that sends signals between these two organs controlling their function,” they added.

Beyond babies

While the majority of the science to date has focused on infants, there is data published in the scientific literature on the potential benefits in adults, with a 2016 study published in the British Journal of Nutrition (Elison et al. Vol. 116, pp. 1356-1368) concluding: “HMO supplementation specifically modified the adult gut microbiota with the primary impact being substantial increases in relative abundance of Actinobacteria and Bifidobacterium in particular and a reduction in relative abundance of Firmicutes and Proteobacteria.”

At the other end of the age spectrum, the bifidogenic effects of HMOs may also make these prebiotics interesting to aging populations, which are characterized by declining Bifidobacteria levels.

Source: Journal of Nutrition & Food Sciences
2021, Volume 4, Issue 1, Page 024
“Human Milk Levels of 2´-Fucosyllactose and 6´-Sialyllactose are Positively Associated with Infant Neurodevelopment and are Not Impacted by Maternal BMI or Diabetic Status”
Authors: E. Oliveros et al.