Health outcomes associated with micronutrient-fortified complementary foods in infants
and young children aged 6-23 months: a systematic review and meta-analysis
Appropriate feeding of infants and young children is essential for healthy growth
and the prevention of stunting, wasting, and overweight. We aimed to assess the beneficial
versus harmful effects of providing fortified complementary foods to children in the
complementary feeding period.In this systematic review and meta-analysis, we searched
the databases Cochrane Central Register of Controlled Trials, MEDLINE, Embase, Cumulative
Index to Nursing and Allied Health Literature, Global Index Medicus, Web of Science,
ClinicalTrials.gov, and WHO International Clinical Trials Registry Platform from inception
to March 9, 2021. We included randomised controlled trials and controlled clinical
trials done in infants and children aged 6-23 months with no identified health problems.
Consumption of foods fortified centrally (ie, during industrial processing) with one
micronutrient or a combination of vitamins, minerals, or both was compared with the
same complementary foods, but without micronutrient fortification. Two review authors
independently screened studies for eligibility, extracted data, assessed risk of bias,
and rated the certainty of the evidence. The main outcomes were growth (measured by
Z scores for weight for age, weight for height or length, and height or length for
age, or other growth measures), stunting, wasting, nutrient adequacy or excess, anaemia,
haemoglobin concentration, iron status, serum zinc concentration, and serum retinol
concentration. We used a random-effects meta-analysis for combining data. This study
is registered with PROSPERO, CRD42021245876.We included 16 studies with 6423 participants,
13 of which were done in malaria-endemic areas. Overall, 12 studies were included
in the quantitative syntheses. We identified five further ongoing studies. There was
no difference between participants who received fortified complementary foods and
those who received non-fortified complementary foods in weight-for-age Z scores (mean
difference -0·01, 95% CI -0·07 to 0·06; five trials; 1206 participants; moderate-certainty
evidence), weight-for-height or length Z scores (-0·05, -0·19 to 0·10; four trials;
1109 participants; moderate-certainty evidence), and height or length-for-age Z scores
(-0·01, -0·21 to 0·20; four trials; 811 participants; low-certainty evidence); stunting
and wasting were not assessed in any study as outcomes. Moderate-certainty evidence
from six trials with 1209 patients showed that providing fortified complementary foods
to children aged 6-23 months reduced the risk of anaemia (risk ratio 0·57, 95% CI
0·39 to 0·82). Those who received fortified complementary foods compared with those
who did not had higher haemoglobin concentrations (mean difference 3·44 g/L, 95% CI
1·33 to 5·55; 11 trials; 2175 participants; moderate-certainty evidence) and ferritin
concentration (0·43 μg/L on log scale, 0·14 to 0·72; six trials; 903 participants;
low-certainty evidence). The intervention led to no effects on serum zinc concentration
(-0·13 g/dL, -0·82 to 0·56; two trials; 333 participants; low-certainty evidence)
and serum retinol concentration (0·03 μmol/L, -0·02 to 0·08; five trials; 475 participants;
moderate-certainty evidence).Fortified complementary foods are effective strategies
to prevent anaemia in infants and young children aged 6-23 months in malaria-endemic
regions. Effects of complementary food fortification should be further investigated
in low-income and middle-income countries, but should also be assessed in high-income
countries, and in regions where malaria is not endemic.WHO.
