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Messaging and methodological considerations when researching breastfeeding and obesity

European Journal of Clinical Nutrition volume 75, pages 1523–1525 (2021)Cite this article

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Identifying modifiable components of human milk that influence infant growth and adiposity is a clinically important objective with potential implications for public health. We commend Enstad and colleagues [1] for their efforts to identify associations between maternal body mass index (BMI) and human milk composition, and downstream associations with infant anthropometrics. This research adds new information to an understudied subject that we have also investigated [2, 3]. However, we are concerned that in several places, the authors’ language implies that milk from mothers with an elevated BMI may predispose their infants to obesity. This is a potentially harmful message that is unsupported by their data due to several methodological limitations. Additionally, this implication is made without acknowledging the extensive evidence that breastfeeding is associated with healthy growth patterns and lower odds of childhood obesity [4], even among children of mothers with obesity [5].

We appreciate the authors’ attempt to address whether the association between maternal BMI and infant growth is attributed, in part, to human milk composition. However, answering this question using observational data requires a mediation analysis, which the authors acknowledge they were underpowered to perform because of the small study population (n = 40). Given this limitation, the implication of mediation in their conclusions is not supported.

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References

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Funding

No financial assistance was received directly in support of this correspondence. The Manitoba Interdisciplinary Lactation Center is supported by the Canada Foundation for Innovation and Research Manitoba. MBA is supported by a Canada Research Chair in the Developmental Origins of Chronic Disease, and is a CIFAR Fellow in the Humans and the Microbiome Program. She receives research funding from the Canadian Institutes of Health Research (CIHR), Research Manitoba, the Canada Foundation for Innovation, the Bill and Melinda Gates Foundation, the Manitoba Children’s Hospital Foundation, Prolacta Biosciences, Mitacs, the Canadian Institute for Advanced Research, and the Garfield G. Weston Foundation. DC is supported by a Canadian Nurses Foundation Scholarship. MB is supported by Mitacs, the Garfield G. Weston Foundation, and a Molly Towel Perinatal Research Foundation Fellowship. ST is supported by a Vanier Canada Graduate Scholarship. AS receives research funding from New Frontiers in Research Funds supported by the Tri-agency Institutional Programs Secretariat, Research Manitoba, the Manitoba Children’s Hospital Foundation, CHRIM, Diabetes Research Envisioned and Accomplished in Manitoba Theme at CHRIM, Japanese Agency for Medical Research and Development, US National Academy of Medicine, and the University of Manitoba. LEK has received funding from CIHR, Research Manitoba, Mitacs, SickKids Foundation, Canadian Cancer Society, Thorlakson Fund, Rady Innovation Fund and CHRIM. NCN is supported by the Public Health Agency of Canada for his work with the Breastfeeding Committee of Canada. He holds research funding from CIHR, Public Health Agency of Canada, Health Canada, Research Manitoba, and the Manitoba Government. None of these entities had any involvement in the development or publication of this correspondence.

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Authors and Affiliations

  1. Manitoba Interdisciplinary Lactation Centre (MILC), Children’s Hospital Research Institute of Manitoba, Department of Pediatrics and Child Health, University of Manitoba, Winnipeg, MB, Canada

    Sarah M. Reyes, Kozeta Miliku, Deborah Chan, Meredith Brockway, Sarah Turner, Katherine A. Kearns, Christina Raimondi, Ayesha Saleem, Lauren E. Kelly, Nathan C. Nickel & Meghan B. Azad

  2. Deparment of Medicine, McMaster University, Hamilton, ON, Canada

    Kozeta Miliku

  3. Department of Epidemiology, Biostatistics, and Occupational Health, McGill University, Montreal, QC, Canada

    Deborah Chan

  4. Department of Community Health Sciences, University of Manitoba, Winnipeg, MB, Canada

    Sarah Turner, Nathan C. Nickel & Meghan B. Azad

  5. Winnipeg Breastfeeding Centre, Winnipeg, MB, Canada

    Katherine A. Kearns & Christina Raimondi

  6. Department of Family Medicine, University of Manitoba, Winnipeg, MB, Canada

    Katherine A. Kearns & Christina Raimondi

  7. Faculty of Kinesiology and Recreation Management, University of Manitoba, Winnipeg, MB, Canada

    Ayesha Saleem & Lauren E. Kelly

  8. George and Fay Yee Centre for Healthcare Innovation, Winnipeg, MB, Canada

    Lauren E. Kelly

  9. Manitoba Centre for Health Policy, University of Manitoba, Winnipeg, MB, Canada

    Nathan C. Nickel

Authors
  1. Sarah M. Reyes
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  2. Kozeta Miliku
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  4. Meredith Brockway
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  5. Sarah Turner
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  6. Katherine A. Kearns
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  7. Christina Raimondi
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  8. Ayesha Saleem
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  9. Lauren E. Kelly
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  10. Nathan C. Nickel
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  11. Meghan B. Azad
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Contributions

SMR, KM, DC, and MBA planned and wrote the initial draft correspondence. All authors provided feedback and approved the final version.

Corresponding author

Correspondence to Meghan B. Azad.

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Conflict of interest

The authors declare no conflicts of interest. They report the following: MBA serves in a volunteer capacity as Secretary to the International Society for Research on Human Milk and Lactation (ISRHML) and as a member of the National Academy of Sciences, Engineering and Medicine Committee on Scanning New Evidence on the Nutrient Content of Human Milk. She regularly speaks at conferences and workshops on infant nutrition, some sponsored by Medela, the Institute for the Advancement of Breastfeeding & Lactation Education, and Prolacta Biosciences. MBA, SMR, and MB have contributed to online courses on breast milk and the infant microbiome produced by Microbiome Courses. SMR serves as the scientific advisor for SimpliFed, created and operates Milk and Microbes, and is currently pursuing the development and patenting of a human milk pasteurizer. She also leads a systematic review for the International Milk Consortium (IMiC) on the associations between human milk analytes and infant/child growth in the first 2 years. ST serves in a volunteer capacity as Trainee Mentorship Series Coordinator to the Trainee Interest Group of ISRHML. KK and CR are co-founders of the Winnipeg Breastfeeding Center. They regularly give presentations to clinical professionals and trainees and about lactation support, without remuneration. NCN served in a volunteer capacity as the Scientific Chair for Breastfeeding at the American Public Health Association and served on the Executive Council for the International Society for Research in Human Milk and Lactation until April 2020. None of these entities had any involvement in the development or publication of this correspondence.

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Reyes, S.M., Miliku, K., Chan, D. et al. Messaging and methodological considerations when researching breastfeeding and obesity. Eur J Clin Nutr 75, 1523–1525 (2021). https://doi.org/10.1038/s41430-021-00867-9

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