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Original Investigation
Caring for the Critically Ill Patient
August 9, 2021

Effects on Growth of Smell and Taste of Milk During Tube Feeding of Preterm Infants: A Randomized Clinical Trial

Author Affiliations
  • 1Mater Research Institute, Faculty of Medicine, The University of Queensland, South Brisbane, Queensland, Australia
  • 2Neonatal Critical Care Unit, Mater Health, South Brisbane, Queensland, Australia
  • 3Office for Research Governance and Development, Gold Coast University Hospital, Southport, Queensland, Australia
  • 4Neonatal Services and Newborn Research, the Royal Women’s Hospital, Melbourne, Victoria, Australia
  • 5Clinical Sciences Research, Murdoch Children’s Research Institute, Parkville, Victoria, Australia
  • 6Department of Obstetrics and Gynaecology, University of Melbourne, the Royal Women’s Hospital, Melbourne, Victoria, Australia
JAMA Pediatr. 2021;175(11):1115-1123. doi:10.1001/jamapediatrics.2021.2336
Key Points

Question  For preterm infants, do regular smell and taste of milk with tube feeding, compared with routine care, improve nutrition and other clinical outcomes?

Findings  In this randomized clinical trial of 396 preterm infants, regular exposure to the smell and taste of milk with tube feeding compared with routine care did not increase weight z scores at discharge. Smell and taste of milk may improve head circumference and length z scores at 36 weeks’ postmenstrual age, but not at discharge.

Meaning  In this randomized clinical trial, although smell and taste of milk with tube feeding did not improve weight z scores at discharge, the combination remains a simple and low-cost intervention without adverse effects and some potential benefits.


Importance  Smell and taste of food increase food anticipation, activate gut motility, and stimulate digestion and metabolism. Despite poor growth of many preterm infants in neonatal intensive care units, the smell and taste of milk with tube feeding are not generally considered a regular component of care.

Objective  To determine the effect of smell and taste of milk with tube feeding on weight z scores at discharge from the hospital.

Design, Setting, and Participants  A randomized, controlled, nonblinded, superiority trial was conducted at 2 perinatal centers between May 9, 2017, and February 1, 2020. Eligible infants (n = 659) were born at less than 29 weeks’ postmenstrual age (PMA) and/or with a birth weight of less than 1250 g.

Interventions  Infants were randomly assigned to receive either the smell and taste of milk with each tube feeding or routine care without the provision of smell and taste of milk.

Main Outcomes and Measures  The primary outcome was weight z score at discharge from any hospital. Secondary outcomes included anthropometric measures at predefined time points, time to full enteral feeds, and other health outcomes associated with prematurity.

Results  Of the 658 infants, a total of 396 infants were randomized; some parents had not been approached for consent (n = 144) or declined participation (n = 117), and 1 infant with consent was not randomized. Of the 396 infants, 196 were assigned to the treatment group (51% male; mean [SD] PMA at birth, 27.5 [2.2] weeks) and 200 were assigned to the control group (52% male; mean [SD] PMA at birth, 27.6 (2.3) weeks). Mean weight z scores at discharge were −0.87 (95% CI, −1.02 to −0.72) for the treatment group and −0.97 (95% CI, −1.11 to −0.83) for the control group (P = .40). The mean difference in z scores between the treatment and control groups at 36 weeks’ PMA was 0.21 (95% CI, 0.01 to 0.4; P = .04) for head circumference and 0.26 (95% CI, 0.05 to 0.51; P = .04) for length. There were no clinically notable differences between the study groups for any other anthropometric, feeding, or health outcomes.

Conclusions and Relevance  In this randomized clinical trial, regular smell and taste of milk included with tube feeding did not improve weight at discharge in preterm infants. Secondary outcomes suggest exposure to smell and taste may improve head circumference and length at 36 weeks’ PMA, but not at discharge. Regular exposure to the smell and taste of milk is a simple and inexpensive intervention with potential benefits and no apparent adverse effects.

Trial Registration  anzctr.org.au Identifier: ACTRN12617000583347

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    1 Comment for this article
    Enhancing Taste and Smell in Preterm Infants
    Harikrishnan Pandurangan, MDS, FDSRCS (Eng), PhD | Clinician Researcher, Craniofacial Orthodontist, Teeth "N" Jaws Center, Lake area, Chennai-600034, India.
    The RCT study is very interesting focussing on the smell and taste of milk during tube feeding in preterm infants and found no weight improvement at discharge. I would like to highlight the following points which might help in increasing the appetite of such infants for weight gain.

    1. As infants have a strong sense of taste having been developed from 16 weeks in-utero, influencing much of taste will stimulate their hunger.

    2. In addition to the taste of milk, as infants are used to the flavoured taste of the favoured food item's of the pregnant
    mother through the amniotic fluid, it is a viable option to use such foods in dilution to help recognised taste sensations.

    3. As the sense of temperature is felt from 20 weeks onwards by infants, there might be role for the temperature of the tested item to enhance reception.

    4. The study also used sleeping infants where the sensations will be at the lowest state of arousal at sleep. Thus ,I feel its always ideal to apply when the infants are awake.

    5. As infants also can smell their mothers, it might be a good idea to involve mothers in applying the milk of test item so that the infants are more attentive.