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Human Milk Oligosaccharides (HMOs): Why are they so Beneficial in infant nutrition1?

5 mins

Breastfeeding is best

Breastfeeding is universally recognised as the optimal nutrition for babies.2-4 UK and WHO guidelines recommend exclusive breastfeeding for the­ first 6 months of an infant’s life, and breastfeeding in combination with balanced, complementary foods thereafter.2-4 Research suggests that breastfed babies have fewer infections and may have a stronger immune system,4 which in part may be due to the presence of human milk oligosaccharides (HMOs) in breast milk.1,5

What are HMOs?

HMOs are complex carbohydrates. Unlike Galacto-oligosachharides and Fructo-oligosachharides (GOS/FOS), HMOs are unique to breast milk and research suggests that they provide immune support to developing infants.1,5-7 HMOs have a unique structure which allows them to provide targeted benefits.

They do this in four main ways:

  • Selectively feeding good bacteria within the gut, where 70–80% of the body’s immune cells live1,6

  • Blocking bad bacteria from attaching to the gut and doing harm1,6–7

  • Strengthening the developing gut barrier1,6–7

  • Helping to balance the immune system1,6

The above benefits have not been shown by GOS/FOS.

SMA® Nutrition have been researching HMOs for 30 years

SMA® Nutrition have been leading research in baby nutrition for over 100 years and are dedicated to learning more about breast milk. Our research into HMO, started in the 1980s and we have been pioneering HMO research for 30 years.

Effects of infant formula with HMOs on growth and mordbidity8


Design & objective:

  • Randomised, multicentre, double-blind trial to evaluate the effects of infant formula supplemented with two HMOs* (2’fucosyllactose [2’FL] and lacto-N-neotetraose [LNnT]) on infant growth, tolerance and morbidity


  • Healthy infants, recruited at 0–14 days old, randomised to either control (n=87) or intervention (n=88) group

Primary Endpoint:

  • Weight gain (g/day) from baseline to age 4 months

Secondary endpoints:

  • Additional anthropometric measures, GI tolerance and behavioural patterns, and morbidity through age 12 months


Primary endpoint

  • No signi­ficant difference in weight gain from baseline to age 4 months between groups

Secondary endpoints

Morbidity – infants who received test (vs control) formula had:

  • 70% lower risk of parent-reported bronchitis through 12 months of age (P≤0.01)

  • 55% lower risk of parent-reported LRTIs through 12 months of age (P<0.05)

  • 56% lower use of antipyretics through 4 months of age (P<0.05)

  • 53% lower use of antibiotics through 12 months of age (P<0.05)

Digestive tolerance – no significant difference between test and control groups

Stool characteristics – significantly softer stools in test vs control group at 2 months (P=0.021)

Behavioural patterns – fewer night-time awakenings were reported in test group at 2 months (P=0.036); in a subgroup of infants delivered by caesarean section, colic at 4 months was reported less frequently in the test group (P=0.035)

Formula intake – mean daily formula intake was similar between groups

The secondary outcome findings showed associations between consuming HMO* -supplemented formula and lower parent-reported morbidity (particularly bronchitis) and medication use (antipyretics and antibiotics). These findings warrant confirmation in future studies.


Infant formula supplemented with HMOs* 2’FL and LNnT is safe, and assists age-appropriate growth.

HMO*: structurally identical human milk oligosaccharides, not sourced from breast milk

  1. Bode L. Human milk oligosaccharides: every baby needs a sugar mama. Glycobiology 2012; 22(9): 1147-62.

  2. World Health Organisation (2002). Infant and young child nutrition: Global strategy on infant and young child feeding. Available at: (accessed January 2022).

  3. Unicef (2015). Improving breastfeeding, complementary foods and feeding practices. Available at: (accessed January 2022)

  4. Victora CG, Bahl R, Barros AJD, et al. Breastfeeding in the 21st century: epidemiology, mechanisms, and lifelong effect. Lancet 2016; 387: 475-90.

  5. Kunz C. Historical aspects of human milk oligosaccharides. Adv Nutr 2012; 3(3): 430S-9S.

  6. Jantscher-Krenn E, Bode L. Human milk oligosaccharides and their potential bene ts for the breast-fed neonate. Minerva Pediatr 2012; 64(1): 83-99.

  7. Smilowitz JT, Lebrilla CB, Mills DA, et al. Breast milk oligosaccharides: structure-function relationships in the neonate. Annu Rev Nutr 2014; 34: 143-69.

  8. Puccio G, Alliet P, Cajozzo C, et al. Effects of infant formula with human milk oligosaccharides on growth and morbidity: A randomized multicenter trial. J Pediatr Gastroenterol Nutr 2017; 64: 624-31.


We believe that breastfeeding is the ideal nutritional start for babies and we fully support the World Health Organization’s recommendation of exclusive breastfeeding for the first six months of life followed by the introduction of adequate nutritious complementary foods along with continued breastfeeding up to two years of age. We also recognize that breastfeeding is not always an option for parents. We recommend that healthcare professionals inform parents about the advantages of breastfeeding. If parents choose not to breastfeed, healthcare professionals should inform parents that such a decision can be difficult to reverse and that the introduction of partial bottle-feeding will reduce the supply of breast milk. Parents should consider the social and financial implications of the use of infant formula. As babies grow at different rates, healthcare professionals should advise on the appropriate time for a baby to begin eating complementary foods. Infant formula and complementary foods should always be prepared, used and stored as instructed on the label in order to avoid risks to a baby’s health. The product be used only on the advice of independent persons having qualifications in medicine, nutrition, pharmacy, or other professionals responsible for maternal and child care