Childhood stunting and micronutrient status unaffected by RCT of micronutrient fortified drink

Abstract

Micronutrient supplementation is widely used to prevent stunting in children under 5 years in low- and middle-income countries (LMIC), but the impact of treatment has been disappointing, possibly due to non-compliance. Our aim was to deliver long-term micronutrient supplementation via a novel, culturally acceptable liquid food to improve linear growth in a high stunting prevalence region.
In a randomised control trial, 971 children aged 6–72 months received either ‘Chispuditos®’ (n = 681), a hot drink (atole) fortified with micronutrients (atole + MN) (9 mg/zinc, 12.5 mg/iron), or lactose-free milk (n = 290) for 18 months. Primary outcomes were changes in length/height-for-age (HAZ) score and the prevalence of stunting at 18-month follow-up. Adherence was monitored monthly, and 73% children in atole + MN group consumed at least half their daily zinc and iron requirement. At 18 months, there was no difference between the treatments in growth [mean change in HAZ −0.02 (95% CI −0.12, 0.08)] or stunting [atole + MN 41%, milk 41%; RR 0.99 (95% CI 0.84, 1.19)]. There were no differences in haemoglobin (HB), ferritin or zinc. No children had iron deficiency anaemia (IDA) at outcome, but zinc deficiency remained equally prevalent in both groups: atole + MN 35%, milk 35% [RR 1.02 (95% CI 0.83, 1.24)]. There was no difference in morbidity between the groups, and micronutrient status was unrelated to HAZ. Long-term micronutrient supplementation via a culturally acceptable food had no impact on stunting or morbidity, raising the question of whether large-scale micronutrient supplementation is worthwhile.

Full text

ORIGINAL ARTICLE
Childhood stunting and micronutrient status unaffected by
RCT of micronutrient fortified drink
Victor Alfonso Mayén
1
| Abimbola Ogunlusi
2
| Charlotte Margaret Wright
3
|
Ada Lizbeth Garcia
2
1
Association for the Prevention and Study of
HIV/AIDS (APEVIHS), Retalhuleu, Guatemala
2
Human Nutrition, School of Medicine,
Dentistry & Nursing, University of Glasgow,
Glasgow, UK
3
Department of Child Health, School of
Medicine, Dentistry & Nursing, University of
Glasgow, Glasgow, UK
Correspondence
Ada Lizbeth Garcia, Human Nutrition, School
of Medicine, Dentistry & Nursing, University
of Glasgow, Room 2.23, Level 2, New Lister
Building, Glasgow Royal Infirmary, 10-16
Alexandra Parade, Glasgow G31 2ER, UK.
Email: ada.garcia@glasgow.ac.uk
Funding information
The Mathile Institute for the Advancement of
Human Nutrition
Abstract
Micronutrient supplementation is widely used to prevent stunting in children under
5 years in low- and middle-income countries (LMIC), but the impact of treatment has
been disappointing, possibly due to non-compliance. Our aim was to deliver long-
term micronutrient supplementation via a novel, culturally acceptable liquid food to
improve linear growth in a high stunting prevalence region.
In a randomised control trial, 971 children aged 6–72 months received either
‘Chispuditos
®
’(n=681), a hot drink (atole) fortified with micronutrients
(atole +MN) (9 mg/zinc, 12.5 mg/iron), or lactose-free milk (n=290) for 18 months.
Primary outcomes were changes in length/height-for-age (HAZ) score and the preva-
lence of stunting at 18-month follow-up. Adherence was monitored monthly, and
73% children in atole +MN group consumed at least half their daily zinc and iron
requirement. At 18 months, there was no difference between the treatments in
growth [mean change in HAZ 0.02 (95% CI 0.12, 0.08)] or stunting [atole +MN
41%, milk 41%; RR 0.99 (95% CI 0.84, 1.19)]. There were no differences in
haemoglobin (HB), ferritin or zinc. No children had iron deficiency anaemia (IDA) at
outcome, but zinc deficiency remained equally prevalent in both groups: atole +MN
35%, milk 35% [RR 1.02 (95% CI 0.83, 1.24)]. There was no difference in morbidity
between the groups, and micronutrient status was unrelated to HAZ. Long-term
micronutrient supplementation via a culturally acceptable food had no impact on
stunting or morbidity, raising the question of whether large-scale micronutrient
supplementation is worthwhile.
1|INTRODUCTION
Global stunting prevalence in children under 5 years of age has
been shown to be slowly declining, but in many countries like
Guatemala, with low human development and severe inequity, it
remains stubbornly high (2020 Global Nutrition Report: Action on
equity to end Malnutrition, n.d.). Stunting is strongly associated with
iron and zinc deficiency, which are still prevalent in low-income
countries (Black et al., 2008) and all are strongly associated with
increased risk of infections and overall morbidity and mortality
Received: 20 March 2021 Revised: 7 July 2021 Accepted: 13 July 2021
DOI: 10.1111/mcn.13256
This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any
medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.
© 2021 The Authors. Maternal & Child Nutrition published by John Wiley & Sons Ltd.
Matern Child Nutr. 2021;e13256. wileyonlinelibrary.com/journal/mcn 1of10
https://doi.org/10.1111/mcn.13256
2022;18:e13256.

(Black et al., 2013). Thus, an extensive body of research has focused
on addressing these problems (Lassi et al., 2020). However, the
results of trials of micronutrient supplementation have been disap-
pointing; some show positive outcomes for iron and zinc status, and
mixed for weight outcomes, but most trials have shown no or only
very small effects on linear growth (Lassi et al., 2020; Petry
et al., 2016; Tam et al., 2020). It has been suggested that this
may reflect poor adherence to the supplementation programmes
(Zaidi et al., 2020).
In Guatemala, stunting affects nearly half of all children under
5 years of age with higher levels in rural and indigenous
populations (2020 Global Nutrition Report: Action on equity to end
Malnutrition, n.d.). Anaemia and iron deficiency are also highly preva-
lent, affecting up to 56% and 81%, respectively (Palacios et al., 2020).
In Guatemala, breastfeeding during the first year of life is highly prev-
alent, though exclusivity is not universal (Colombara et al., 2015), but
the transition to solid foods is marked by poor quality and quantity of
complementary foods. The diet in Guatemala tends to be monoto-
nous, plant based and high in phytates (Arsenault & Brown, 2017;
Vossenaar et al., 2018), with limited intake of animal source or
nutrient-dense foods, particularly bioavailable sources of iron and
zinc. For decades, an approach to fighting chronic malnutrition in
Guatemala has been to provide fortified food supplements, and food
aid programmes are well established and valued by governments and
non-governmental organisations alike. However, compliance issues
and reduced evidence of long-term impact on stunting reduction are
reported (Hossain et al., 2017). In Guatemala, ‘atoles’(hot starch-
based drinks) are culturally accepted and form part of the diet
pattern. In order to increase the acceptability and thus compliance
with supplementation programmes, a drink-based supplement
(Chispuditos
®
) was developed, which was fortified with high levels of
zinc iron and other vitamins and minerals, thought to be important
for longitudinal growth. This novel food was administered in two dif-
ferent longitudinal cohorts of toddlers attending nurseries in Guate-
mala city over a period of 2.5 and 4 years with pre- and post-
measurements of growth and findings suggesting small but promising
improvements in stunting and iron status (Villanueva et al., 2015;
Villanueva & Reinhart, 2013). Thus, the aim of this study was to test
in a randomised control trial (RCT) the hypothesis that providing extra
micronutrients via this culturally acceptable liquid food over an
extended period would reduce stunting, improve zinc and iron status
and reduce morbidity compared to an energy/protein-matched milk
with no added micronutrients.
2|METHODS
2.1 |Study design and sample size
This was an open-label RCT (Registration NCT01643187) conducted
between 2012 and 2013 in the southwest region of Guatemala in
18 rural communities and one urban district, San Felipe, Retalhuleu.
Participants received an atole +MN, or lactose-free milk
(henceforth referred as milk), over 18 months with a 7:3 ratio of
intervention to control. The original protocol did not calculate power,
but post hoc calculations based on the sample size used suggest that
the study was 80% powered at 0.05 level to detect a difference
between the two groups at follow-up of 0.22 height z-scores using
the Altman nomogram (Altman, 1980) and a reduction in stunting
from 40% to 31% (Epi Info StatCalc 7.2.3.1).
2.2 |Participants, inclusion criteria and
recruitment
All families with children aged 6–72 months of age living in the
study sites were invited to take part in a nutritional screening
programme coordinated by the non-governmental organisation
APEVIHS (Asociaci
on Para la Prevenci
on y Estudio del VIH/SIDA)
with approval of the local authorities. All parents were informed of
the study, and if their children were in the age range of
6–72 months, they were invited to take part. Following parental
signed consent, children were measured, and socio-demographic
information was recorded. Criteria for inclusion in the study were
then presenting a degree of malnutrition in the form of being
<1SD for weight, height or WHZ while not suffering from any
severe health problem.
Participants were allocated to intervention (70%) and control
groups (30%) using a computer-generated random allocation proce-
dure stratified by community and age group.
2.3 |Intervention
The fortified atole (Chispuditos
®
) consisted of a daily dose of 18.75 g
powder to be cooked with water and 18.75 g of sugar. The amount of
powdered drink to be supplemented by the families was measured
using a standardised plastic scoop provided to the families. The con-
trol drink consisted of 27 g of lactose-free milk (De-lactosed Nido
®
,
Nestle, Centro America) provided as powder to be reconstituted with
water (Table 1). The supplements were delivered to each child at their
Key messages
•Multivitamin mixes including zinc are widely used in food
supplementation programmes for stunting prevention.
•Meta-analyses suggest these may have effect on growth
and morbidity, but many earlier studies were small and/or
short term and may have had poor compliance.
•Despite long-term supplementation with a culturally
acceptable fortified atole, no effect was found on growth
or morbidity.
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homes every 24 days for 18 months in a bag without commercial
names of 450 g for Chispuditos
®
and 648 g of milk. Families supplied
their own sugar, which is widely available. Instructions on preparation
and distribution were given to the mother/career. Both drinks pro-
vided 4 g protein per day but differed slightly in energy contribution
(30 kcal less in the control drink); the total volume instructed to be
given was 8 fluid oz. (240 ml).
2.3.1 | Data collection
Anthropometry and blood samples were obtained at baseline and end
point. Compliance and markers of morbidity were checked by staff
monthly but recorded only three times for compliance and twice for
morbidity. Information on socio-economic status and mothers'
education were obtained at the start of the trial.
2.3.2 | Anthropometry
Anthropometric measures included weight, height/length and mid-
upper arm circumference (MUAC). Weight was measured with a
Roman-type ‘paediatric scale’with a precision of 10 g and expressed
from 10 to 100 g. Height/length was measured using a portable infant
meter calibrated in cm. For the MUAC, the circumference of the non-
dominant arm was measured with a band tape to the nearest 0.1 cm.
‘WHO Anthro software’was used to calculate the z-scores of growth
indicators and MUAC.
TABLE 1 Nutrient composition and
amounts per portion of made-up atole
+MN (Chispuditos
®
) and lactose-free
milk (Milk)
Atole +MN (Chispuditos
®
) Milk
b
RNI/day
Nutrients Unit Quantity Quantity
Energy Kcal 147.8
a
116 1165
Protein g 4 4.1 14.5
Carbohydrate g 87
a
16.1
Fat g 1 3.9
Zinc mg 9 1.5 5.0
Iron mg 12.5 1.9 6.9
Folic acid μg 160 243 70
Iodine μg 90 N/R 70
Vitamin A μg 250 64.8 μg 400 μg
Vitamin C mg 40 40 25 mg
Vitamin B
12
μg 0.9 N/R 0.4 mg
Vitamin B
6
mg 0.5 0.13 0.2 mg
Niacin mg 6 1.85 4 mg
Vitamin B
2
mg 0.5 N/R 0.2 mg
Vitamin B
1
mg 0.5 0.12 0.4 mg
Copper mg 0.3 N/R 0.5 mg
Vitamin D
3
mg 5 0.000945 0.007 mg
Vitamin E mg 5 0.00135 0.4 mg
Calcium mg 200 243 400 mg
Phosphorus mg 150 N/R 400 mg
Magnesium mg 40 N/R 80 mg
Selenium μg 17 N/R 10 μg
Manganese μg 0.17 μg N/R 16 μg
Pantothenic acid mg 1.8 mg 0.59 1.7 mg
Biotin μg8μg N/R 2.4 μg
Note: Parents were instructed to prepare Chispuditos
®
using 18.75 g of Chispuditos
®
and the equivalent
measurement of sugar mixed with 8 oz. of water (240 ml) and boil for 8 min.
Abbreviations: N/R, not reported by the manufacturer; RNI, UK Recommended Nutrients Intake for age
group 1-3 years.
a
Energy contribution increased from 73 to 147.8 and carbohydrate from 12 to 87 with addition of
18.75 g of sugar.
b
De-lactosed milk (Nido
®
, Nestle) in powder form; the amount recommended was a standardised
measure of 27 g to be mixed with 8 oz. of boiled water (240 ml).
ALFONSO MAY
EN ET AL.3of10

2.3.3 | Blood measurements
For biomarkers, samples were drawn into trace-element-free tubes by
trained staff to test for haemoglobin, serum zinc and serum ferritin.
The Guatemalan National Micronutrient Survey (ENMICRON
2009–2011) procedures were used to ensure the integrity of blood
samples from the field of laboratory (Ministerio de Salud Publica y
Asistencia Social [MSPAS], 2010). For haemoglobin, whole blood was
analysed using an auto haematology analyser (RT-7600 Rayto,
Shenzhen, China), and the results were confirmed using peripheral
smear and microscopy. Serum zinc (samples >20 μl) were determined
using atomic emission spectrometry (MP-AES 4200, Agilent Technolo-
gies, Australia). The chemiluminescence immunoassay method was
used to analyse serum ferritin with Maglumi 1000 (SNIBE, Shenzhen,
China). C reactive protein (CRP) and α-acid glycoprotein AGP1 were
analysed using nephelometry with a BN ProSpec Siemens
®
system.
Lab analysis was conducted in the Institute of Central American and
Panama laboratories and the University of Colorado.
2.3.4 | Assessment of compliance and morbidity
Monthly home visits by researchers were conducted to check how
the drink was being made up and monitor compliance in both treat-
ment groups. On three occasions at median 27, 42 and 60 weeks from
baseline, the researchers also weighed the current bag of atole
+MN/milk and recorded the number of days since it had been
delivered.
At the start of the intervention, children in both groups who were
>24 months and that had not previously been dewormed in the last
6 months were given oral paediatric deworming treatment. At two
home visits at median 36 and 79 weeks from baseline, research staff
recorded if in the last 2 weeks a child had been referred to the health
centre for, dehydration, haemorrhages, difficulty in breathing or
diarrhoea.
2.4 |Statistical analysis
Data were analysed using the Statistical Package for the Social
Sciences (SPSS) software, Version 24. Height/length-for-age z-score
(HAZ), weight-for-height z-score (WHZ) and weight-for-age z-score
(WAZ) were assessed using the WHO growth reference standards
(30) values < 2SD were taken for stunting, wasting and under-
weight, respectively. For the standardised anthropometric scores, out-
liers above +6 and 6 for the LAZ and WAZ z-scores were identified
and removed.
For the analysis of serum ferritin, we excluded participants with
inflammation, AGP ≥1. IDA was defined as haemoglobin concentra-
tion lower than 11 g/dl with serum ferritin concentration less than
12 μg/dl. Low zinc levels were defined according to WHO standards
as serum zinc lower than 65 μg/dl for children under 10 years of age
(de Benoist et al., 2007).
For the morbidity, participants were categorised as having had
none, one or more than one of the diseases investigated.
For each compliance occasion, the total amount of product used
(weight of bag when full weight of bag at visit) was divided by the
number of treatment days to give a weight per day. Then, the mean
for each child was calculated. Where one of the three values was
missing, the mean of two was taken, and where two were missing, the
sole value was used. The full dose of atole +MN (18.75 g) supplied
nearly twice the RNI for zinc and iron so that 10 g would fully meet
the child's requirements.
2.4.1 | Outcomes
This analysis of the trial data was undertaken in Glasgow 6 years after
data collection was complete. All analyses were performed using the
original randomised groups. Before handling the data, an analytical
plan was agreed with those who had conducted the trial, specifying
plausible primary and secondary outcomes, given the high rates of iron
and zinc deficiency and their known effects. The primary outcomes as
specified at registration were change in HAZ to and the percentage
stunted at 18-month follow up. Four secondary outcomes were
change in haemoglobin and zinc and prevalence of IDA and zinc defi-
ciency at 18 months. A subgroup analysis was performed to determine
if there was an association between the outcomes and potential con-
founders including age, anaemia (HB < 11 g/l) status at baseline and
the level of compliance with the treatment. The Bonferroni correction
method was applied, dividing the conventional threshold for statistical
significance (0.05) by the number of statistical tests performed.
2.5 |Ethical considerations
Parental written consents were obtained from each eligible child at
the time of enrolment. The study was approved by the ethics
committee of the Esperanza University Hospital, University Francisco
Marroquin, Guatemala.
3|RESULTS
A total of 1238 children were screened, and 971 met the criteria and
were included in the study.
Of the 971 children initially enrolled to participate in the study,
681 were allocated to receive atole +MN and 290 to receive milk. Of
the total sample size, 54 children were lost to follow-up (Figure 1):
5.6% in the atole +MN group and 2.4% in the milk group (P=0.058).
3.1 |Baseline characteristics of the participants
Overall, the two treatment groups did not differ significantly in any of
the variables examined at baseline (Table 2). Stunting and anaemia
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were present at baseline in around half of both groups, with 10% hav-
ing IDA. There were slightly higher rates of zinc deficiency in the
atole +MN (31.4%) than in the milk group (25.3%) at baseline, but
this was not statistically significant (P=0.057).
3.2 |Compliance
815 children had data at each monitoring occasion, 102 for two
and 33 at only one occasion, whereas 21 had none, meaning that
there was at least some compliance data for 950 children. The mean
(SD) intake of atole +MN per day was 15.9 (6)g overall, and 80%
of that group consumed 10 g or more, thus fully meeting their
RNI for iron and zinc from the supplement alone, whereas 23%
consumed 20 g.
3.3 |Effect of micronutrient supplementation on
growth, micronutrient status and morbidity
The mean change in height/length did not differ significantly
between the two groups or for any other growth variables. There was
an overall decrease in the prevalence of stunting at 18-month
follow-up in both groups (48.4/47.9% at baseline vs. 40.6/40.7 at
FIGURE 1 Consort diagram of study participants' progression through the trial
ALFONSO MAY
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follow-up for atole +MN/milk), but the relative risks were not
statistically significant (Table 4).
Rates of anaemia and IDA fell markedly over time, but rates of
zinc deficiency remained high (Table 4). There was no consistent
difference between the two treatment groups for any micronutrient
status variable evaluated (Table 3) or in the relative risk of micronu-
trient deficiency. There was a trend (P=0.09) to less decline in
serum zinc in the intervention group, but no difference in the
proportion with low zinc. The milk group had significantly higher HB
and were less likely to be anaemic, but there was no difference in
ferritin or rates of iron deficiency. Overall, 36% of participants in the
atole +MN against 26% for the milk group had at least two of the
investigated diseases during the study period, but there was no
difference in morbidity score between the two treatment groups
(Table S1).
At baseline, micronutrient status was unrelated to height or
weight in the whole cohort. At follow-up, there was a weak correla-
tion between HAZ and serum zinc (r=0.08, P=0.011) and between
change in HAZ and serum zinc (r=0.07, P=0.038). When this
analysis was restricted to the atole +MN group, the effect was
slightly enhanced for LAZ (r=0.1, P=0.016) but was no longer
significant for change in LAZ.
3.4 |Effect of micronutrient supplementation in
different subgroups
The subgroup analysis suggested no differences in relative risks for
stunting, ID, anaemia and zinc deficiency between the subgroups by
age at baseline or anaemia at baseline. There were too few cases of
IDA at follow-up to examine subgroup effects (Table S2).
In the atole +MN group, there was a weak correlation between
the amount of supplement consumed and serum zinc levels (r=0.08,
P=0.046) and a borderline association with change in zinc (r=0.07,
P=0.084). The 123 children consuming less than 10 g were also
more likely to be zinc deficient (45%) compared with those consuming
>10 g (33% P,χ
2
=0.01). There was no association between intake
and zinc status in the milk group.
TABLE 2 Baseline characteristics of participants according to treatment groups
Variable Atole +MN (n=681) Milk (n=290) P-value
Sex, n(%) 0.645
Male 328 (48.2) 135 (46.6)
Female 353 (51.8) 155 (53.4)
Continuous variables, mean ± SD
Age (months) 37.72 ± 20.4 38.54 ± 20.2 0.566
Initial body weight (kg) 12.10 ± 3.59 12.28 ± 3.53 0.484
Height/length (cm) 86.96 ± 13.6 87.66 ± 13.65 0.468
BMI (kg/m
2
) 15.78 ± 1.79 15.76 ± 1.83 0.885
MUAC (cm) 15.29 ± 1.44 15.32 ± 1.49 0.791
Length-for =-age z-score (LAZ) 2.02 ± 0.99 2.03 ± 1.04 0.864
Weigh-for-height z-score (WHZ) 0.21 ± 1.17 0.20 ± 1.25 0.826
Weight-for-age z-score (WAZ) 1.31 ± 1.01 1.30 ± 1.09 0.900
Haemoglobin (g/dl) 12.24 ± 1.07 12.28 ± 3.53 0.804
Serum ferritin (μg/dl) 31.17 ± 21.07 33.92 ± 36.44 0.190
Serum zinc (μg/dl) 71.43 ± 13.67 73.76 ± 14.15 0.273
AGP (g/l) 0.73 ± 0.26 0.72 ± 0.29 0.705
Categorical variables, prevalence, n (%)
Stunting (LAZ < 2SD) 329 (48.4) 137 (47.9) 0.970
Wasting (WHZ < 2SD) 37 (5.5) 19 (6.7) 0.455
Underweight (WAZ < -2SD) 135 (19.9) 53 (18.7) 0.656
Iron deficiency (serum ferritin < 12 μg/dl) 86 (15.2) 33 (13.9) 0.644
Anaemia (HB < 11 g/dl) 63 (10) 27 (10.1) 0.953
Iron deficiency Anaemia (HB < 11 g/dL and serum
ferritin < 12 ug/dl)
13 (2.1) 6 (2.3) 0.853
Low zinc level, (zinc level < 65 ug/dl) 210 (31.4) 71 (25.3) 0.057
Inflammation (AGP ≥1 g/l) 71 (11.5) 25 (9.9) 0.494
Abbreviations: AGP, alpha-1-acid-glycoprotein; HAZ, height-for-age z-score; HB, haemoglobin; LAZ, length/height-for-age z-score; SD, standard deviation;
WAZ, weight-for-age z-score; WHZ, weight-for-height z-score.
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TABLE 3 Mean change between baseline and 18-month follow-up and comparison between treatment groups (continuous outcome data)
Variables
Atole +MN Milk
Mean change between treatment groups (mean
± SD)
Comparison between groups
a
, atole
+MN vs. milk at 18 months
Baseline (mean
± SD)
18 months
(mean ± SD)
Baseline (mean
± SD)
18 months
(mean ± SD)
Atole +MN (n=681)
(mean ± SD)
Milk (n=290)
(mean ± SD)
Mean
difference 95% CI P- value
Growth
Height (cm) 86.96 ± 13.6 102.36 ± 11.3 87.66 ± 13.65 103.32 ± 10.93 15.33 ± 3.93 15.26 ± 3.91 0.076 0.49, 0.65 0.793
Height z 2.01 ± 0.99 1.87 ± 0.94 2.03 ± 1.03 1.82 ± 0.93 0.17 ± 0.69 0.19 ± 0.61 0.018 0.12, 0.08 0.712
Weight (kg) 12.10 ± 3.59 16.47 ± 3.94 12.28 ± 3.53 16.84 ± 3.63 4.39 ± 1.66 4.51 ± 1.40 0.116 0.35, 0.11 0.322
Weight z 1.31 ± 1.01 1.17 ± 0.89 1.32 ± 1.01 1.10 ± 0.81 0.14 ± 0.87 0.18 ± 0.78 0.053 0.18, 0.07 0.393
WHZ 0.22 ± 1.16 0.01 ± 0.91 0.21 ± 1.16 0.08 ± 0.78 0.22 ± 1.12 0.30 ± 1.03 0.069 0.23, 0.09 0.392
MUAC (cm) 15.29 ± 1.44 16.79 ± 1.56 15.32 ± 1.49 16.86 ± 1.38 1.50 ± 1.13 1.52 ± 1.11 0.026 0.19, 0.14 0.753
Micronutrient status
Serum HB (g/dl) 12.24 ± 1.07 12.28 ± 0.86 12.22 ± 1.11 12.40 ± 0.80 0.02 ± 1.13 0.19 ± 1.06 0.171 0.3, 0.0 0.048
Serum ferritin (μg/l) 31.17 ± 21.07 47.35 ± 36.00 33.92 ± 36.44 48.48 ± 25.58 15.56 ± 28.35 12.20 ± 42.00 3.371 2.5, 9.2 0.257
Serum zinc (μg/dl) 71.43 ± 13.67 69.99 ± 12.27 73.76 ± 14.22 70.15 ± 12.07 1.35 ± 16.04 3.43 ± 16.77 2.079 0.3, 4.5 0.088
Abbreviations: HB, haemoglobin; Z =Z-score for age and gender; WHZ, Weight-for-Height-Z-score.
a
Group comparison using independent t-test.
ALFONSO MAY
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4|DISCUSSION
This trial found that 18 months' use of a liquid food supplement
fortified with micronutrients had no impact on either the growth or
the micronutrient status of rural Guatemalan infants and preschool
children, compared with an isoenergetic lactose-free milk. This is
disappointing, as reduction in the rates of stunting and IDA was
observed when the same atole +MN (Chispuditos
®
) was given as a
supplement to urban toddlers in an uncontrolled study in nurseries
in Guatemala City (Villanueva et al., 2015; Villanueva &
Reinhart, 2013).
Strengths of this study were its large-scale and long follow-up
and its use of a culturally acceptable food supplement. This could be
drunk as part of the family meal pattern, mostly as a part of breakfast,
to counteract the problems of non-compliance described in previous
trials (Ramakrishnan et al., 2009; Zaidi et al., 2020). Compliance was
monitored monthly, and objective measures collected at three cen-
suses point suggested that 84% of children in the intervention
received at least the RNI of iron and zinc daily, whereas 30% received
more than double the RNI.
There were some limitations of this study. The drinks were not
fully equivalent in energy contribution, but the difference was very
small (30 kcal higher in the atole +MN). Ethical concerns led to a
7:3 allocation ratio, but the numbers treated still represent a larger
sample than most already published trials. Participants and measurers
were not blinded to the treatment received, but analysis of the blood
samples was performed blind, and the absence of any observed
differences makes assessment bias unlikely. In our study population,
the prevalence of anaemia and IDA was lower than in some previous
studies (De-Regil et al., 2011; Thompson et al., 2013), and there was
no IDA in either group at follow-up. There was no trend to increased
effects in those who were iron or zinc deficient at baseline, so the role
of iron in this supplement had not really been tested in this trial. The
age range of the children at baseline was wide, and those aged over
24 months were less likely to benefit from any intervention to prevent
stunting. However, there was no suggestion of an intervention effect
in the younger children (Table S3).
These findings are mainly in keeping with what is now known
from other trials assessing the effect of zinc supplementation in
isolation or combination. Since this trial was completed, a systematic
review and meta-analysis reported similarly null findings in relation to
growth, but still reported some benefits (Petry et al., 2016) Most
recently, a review suggested that micronutrient supplementation
alone ‘slightly increased length-for-age z-scores’(Lassi et al., 2020).
The latter review aimed to include grey as well as published literature,
but it is of note that this trial's results were not included. We could
identify only four other published studies including zinc supplementa-
tion of larger scale than this one (Barffour et al., 2019; Becquey et al.,
2016; Bhandari et al., 2002; McDonald et al., 2015). Each reported at
least one significant finding, but these were not consistent, and none
found positive effects on growth. It is thus imperative that null trial
results like these are also published, because there is risk that small
effects detected in large meta-analyses simply reflect publication bias.
Despite the high prevalence of zinc deficiency at baseline, we
found only limited evidence of an effect of atole +MN on serum zinc,
as those randomised to that treatment had only slightly higher serum
zinc, a difference that was non-significant (P=0.09). No difference
was seen between the randomised groups in rates of deficiency,
though the children who consumed more than their RNI of zinc were
less likely to be zinc deficient. In a recent meta-analysis, six of the
19 RCTs with relevant data had similarly found no significant
difference in serum zinc at follow-up (Tam et al., 2020). Because zinc
plays a crucial role in cell function, serum levels are maintained in a
tight homeostatic range, so serum zinc levels are a poor reflection of
total body zinc (Hess et al., 2007). A previous meta-analysis of
18 RCTs found great heterogeneity between studies and suggested
that doubling the intake of zinc only increased the serum/plasma zinc
status by 9% (Moran et al., 2012). The follow-up in this study was
longer than most published studies, and it has been suggested that
the increases in zinc levels due to supplementation may decline with
TABLE 4 Relative risk for outcomes at 18 months between treatment groups
Variable at 18 months Atole +MN/milk (%) RR (95%CI) P-value
a
Stunting (LAZ < 2SD) 40.6/40.7 0.99 (0.84, 1.19) 0.971
Wasting (WHZ < 2SD) 5.6/6.7 0.84 (0.49, 1.43) 0.519
Underweight (WAZ < 2SD) 13.2/12.0 1.10 (0.75, 1.62) 0.630
Anaemia (HB < 11 g/dl) 7.3/3.6 2.02 (1.02, 4.14) 0.043
Iron deficiency (ID) (serum ferritin < 12 μg/dl) 1.6/0 N/A
b
N/A
b
IDA (HB < 11 g/dl and serum ferritin < 12 μg/l) 0/0 N/A
b
N/A
b
Low zinc (serum zinc < 65 μg/dl) 35.4/34.9 1.02 (0.83, 1.24) 0.878
Morbidity
c
10.6/9.2 1.16 (0.75, 1.16) 0.505
Abbreviations: CI, confidence interval; HB, haemoglobin; IDA, iron deficiency anaemia; LAZ, length/height-for-age z-score; N/A, not applicable; SD,
standard deviation; WAZ, weight-for-age z-score; WHZ, weight-for-height z-score.
a
The significance level was set at P=0.006 (Bonferroni correction method).
b
It was not possible to calculate the relative risk because of lack of cases in the atole +MN group.
c
Morbidity was defined as the presence of one or more of the diseases including diarrhoea, dehydration, difficult breathing, diarrhoea with blood, bleeding
and bronchitis at the end point assessment.
8of10 ALFONSO MAY
EN ET AL.

time (Hess et al., 2007). Thus, it is possible that total body zinc dif-
fered when serum levels did not.
Low levels of serum zinc prevalent in Guatemala have been attrib-
uted to poor zinc absorption ‘poor intrauterine zinc accretion’from
poor maternal status and gastrointestinal dysfunction (Krebs
et al., 2014). This was thought to relate to high phytate consumption,
though one trial in Guatemala found no increase in zinc absorption
with reduced phytate consumption (Mazariegos et al., 2006). Thus,
even if the zinc is taken, it is not necessarily absorbed.
Micronutrient fortified drinks are a relatively cheap, culturally
acceptable powdered milk replacement in vulnerable communities
where lactose intolerance is common and fluid milk is expensive and
impractical. As such, this is a popular form of food aid that can
facilitate engagement with vulnerable families. However, the hopes
that such fortified drinks alone would prove to be the answer to
Guatemala's exceptionally high rates of stunting have not been borne
out, not only on the evidence of this trial but also from the worldwide
evidence of lack of effect of such preventive supplementation on
growth. The lack of effectiveness of solely nutritional programmes
suggests the need to seek other explanations and possible solutions.
Stunting is an intergenerational problem, and much stunting has its
origins before birth, so earlier interventions focusing on adolescent
nutrition need to be considered for future programmes (Martorell &
Zongrone, 2012). Childhood infections are highly prevalent in poor
resource settings; as well as impacting absorption from the gut, recur-
rent inflammation may also act directly on the growth plate (Krebs
et al., 2014; Owino et al., 2016). So far, WASH programmes combined
with supplementation have also failed to demonstrate strong efficacy
(Null et al., 2018), but these have not been able to address the pro-
found underlying factors that lead to poor hygiene and limited diet. It
is clear from large birth cohorts from LMIC (India, the Philippines,
South Africa, Guatemala, Brazil) that child stunting is a strong
determinant of reduced human capital (Richter et al., 2011).
Guatemala remains one of the poorest and most unequal countries in
Latin America. More than half of the Guatemalan population live
below the national poverty line, and about a quarter of the population
lives in extreme poverty (Instituto Nacional de Estadistica [National
Statistics Institute], 2017). The structural and underlying causes of
malnutrition, poverty, household food insecurity and poor access to
healthcare facilities that are driven by socio-demographic inequalities
remain unsolved in these settings.
In conclusion, this trial observed no impact of long-term preven-
tative supplementation with micronutrients added to a culturally
accepted drink on either growth or micronutrient status in infants and
young children in rural Guatemala. This suggests a need to review the
usefulness and cost effectiveness of widespread supplementation
programmes.
ACKNOWLEDGMENTS
The study was funded by The Mathile Institute for the Advancement
of Human Nutrition. We are in deep gratitude to the municipality of
San Felipe, Retalhuleu, Guatemala, and local community leaders who
supported this study. We thank all families who took part in this study.
CONFLICTS OF INTEREST
The authors declare that they have no conflicts of interest.
CONTRIBUTIONS
VAM designed and conducted research; AO and CMW analysed
data; AO, ALG and CMW wrote the paper. ALG was responsible
for the paper's final content. All authors read and approved the
final manuscript.
DATA AVAILABILITY STATEMENT
The data that support the findings of this study are available from the
corresponding author upon reasonable request.
ORCID
Charlotte Margaret Wright https://orcid.org/0000-0001-6256-
6315
Ada Lizbeth Garcia https://orcid.org/0000-0002-3526-2380
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SUPPORTING INFORMATION
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How to cite this article: Alfonso Mayén, V., Ogunlusi, A.,
Wright, C. M., & Garcia, A. L. (2021). Childhood stunting and
micronutrient status unaffected by RCT of micronutrient
fortified drink. Maternal & Child Nutrition, e13256. https://doi.
org/10.1111/mcn.13256
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