Consumption of growing up milk and stunting among Indonesian toddlers

TO THE EDITOR: Study on nutrition for infants and young children faces the challenge of innate study design bias. In the paper titled “Daily consumption of growing-up milk is associated with less stunting among Indonesian toddlers,” reported by Sjarif et al1 published on issue 1 year 2019 concluded that daily consumption of 300 ml of growing-up milk (GUM) may be considered a preventative measure against stunting. This conclusion needs to be interpreted carefully. The study was not originally designed to assess whether GUM consumption prevents stunting. Moreover, this cross-sectional study had a small sample size and was designed to validate “Ironcheq”, a questionnaire to detect the risk of iron deficiency in toddlers but not for stunting. The authors also conducted a subgroup analysis comparing the daily consumption of GUM in 41 children with stunting (defined as height-for-age or length-for-age Z score <-2) and 131 without stunting (defined as height-for-age or length-for-age Z score >-1). This observational and cross-sectional study was not appropriately designed to explore stunting prevention.

Moreover, Ironcheq validation study remains unpublished and there are several highlighted limitations of the questionnaire. The tool only contains five questions asking about the amount of formula or GUM consumed per day (presumably assuming nutrition equivalence); portions of chicken or beef liver (but no other organ meat) consumed per week; portions of red meat (explicitly excluding chicken and fish) per week; portions of red meat products per week; and the number of eggs (one portion equating to one chicken, one duck, or three quail eggs, irrespective of their differing nutritional qualities) per week. Rather than providing detailed information on intake, participants were only given a score from 0 to 2 on each question to quantify consumption. This grading scale is arbitrary at best and the description of portion sizes is entirely inadequate. For example, a portion size of one chicken liver was said to be equivalent to a “matchbox sized” beef liver. Furthermore, Ironcheq questionnaire did not differentiate between consumption between “formula” and “GUM”. Infant formula with GUM was incorrectly referred by CODEX STAN 72-1981 for infant formula and formulas for special medical purposes for infants.2 No further information was given on the “formula” referred to question in the questionnaire. The study did not investigate about the specific consumption of cow or goat milk and nor did they consider whether the children were breastfed. It is not clear whether parents were asked to describe their child’s usual intake or reflect only on their intake in the previous week. As stunting is associated with chronic undernutrition, a short recall periods for examining the children’s consumption is poor indicator of regular consumption in the past 12 months or more.3

The analytical approach of this article is questionable. A significant concern is that there may be systematic nutrition-sensitive differences between stunted and non-stunted children (e.g., wealth, nutritional knowledge, and women’s empowerment). The authors provided limited information on how they controlled potential bias by controlling only age and gender as potential confounders. However, the etiology of stunting is multifaceted. Childhood stunting may be influenced by maternal undernutrition before and during pregnancy, infectious diseases, inadequate or inappropriate complementary feeding, and poor sanitation practices in households and communities.4–5

It is well recognized that stunting requires interdisciplinary strategies for its reduction.3 However, this study only used single factor in finding the association between daily consumption of 300 ml GUM and stunting, thereby indicating a lack of understanding about factors associated with stunting.

A large research organization has recommended to improve nutritional diets during the first 1,000 days, including dietary diversification and complementary feeding practices improvement while considering the local context as preventive efforts against stunting.4–5 Evidences from clinical trials indicated that several of these strategies, both prenatal and postnatal, can have a positive impact on child growth.

Moving forward, researchers in the field must incorporate all point to their studies. The conclusion of study by Sjarif et al1 need to be furtherly examined by considering these complexities and using better study design to generate more acceptable conclusion.

1. Sjarif DR, Yuliarti K, Iskandar WJ. Daily consumption of growingup milk is associated with less stunting among Indonesian toddlers. Med J Indones. 2019;28(1):70–6.
2. Codex Alimentarius Commission. Standard for infant formula and formulas for special medical purposes intended for infants: Codex STAN 72–1981. Codex Alimentarius Commission. 2015.
3. Thorne-Lyman A, Spiegelman D, Fawzi WW. Is the strength of association between indicators of dietary quality and the nutritional status of children being underestimated? Matern Child Nutr. 2014;10(1):159–60.
4. de Onis M, Branca F. Childhood stunting: a global perspective. Matern Child Nutr. 2016;12 Suppl 1(Suppl 1):12–26.
5. Torlesse H, Cronin AA, Sebayang SK, Nandy R. Determinants of stunting in Indonesian children: evidence from a cross-sectional survey indicate a prominent role for the water, sanitation and hygiene sector in stunting reduction. BMC Public Health. 2016;16:669.

https://doi.org/10.13181/mji.cor.204566

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