Health effects of micronutrient fortified dairy products and cereal food for children and adolescents: A systematic review

PLoS One. 2019 Jan 23;14(1):e0210899. doi: 10.1371/journal.pone.0210899. eCollection 2019.

Abstract

Introduction: Micronutrient (MN) deficiencies cause a considerable burden of disease for children in many countries. Dairy products or cereals are an important food component during adolescence. Fortification of dairy products or cereals with MN may be an effective strategy to overcome MN deficiencies, but their specific impact on health in this age group is poorly documented.

Methods: We performed a systematic review and meta-analysis (registration number CRD42016039554) to assess the impact of MN fortified dairy products and cereal food on the health of children and adolescents (aged 5-15 years) compared with non-fortified food. We reviewed randomised controlled trials (RCT) using electronic databases (MEDLINE, EMBASE, Cochrane library; latest search: January 2018), reference list screening and citation searches. Three pairs of reviewers assessed 2048 studies for eligibility and extracted data. We assessed the risk of bias and applied GRADE to rate quality of evidence.

Results: We included 24 RCT (often multi MN fortification) with 30 pair-wise comparisons mainly from low- and middle income countries. A very small and non-significant increase of haemoglobin values emerged (0.09 g/dl [95%-CI: -0.01 to 0.18]; 13 RCT with iron fortification; very low quality of evidence). No significant difference was found on anaemia risk (risk ratio 0.87 [95%-CI: 0.76 to 1.01]; 12 RCT; very low quality), but a significant difference in iron deficiency anaemia favouring fortified food was found (risk ratio 0.38 [95%-CI: 0.18 to 0.81]; 5 RCT; very low quality). Similar effects were seen for fortified dairy products and cereals and different fortification strategies (mono- vs. dual- vs. multi-MN). Follow-up periods were often short and the impact on anthropometric measures was weak (low quality of evidence) Very low quality of evidence emerged for the improvement of cognitive performance, functional measures and morbidity.

Conclusions: Fortification of dairy products and cereal food had only marginal health effects in our sample population from 5-15 years. Further evidence is needed to better understand the health impact of fortified dairy products and cereals in this age group.

Systematic review registration: The study protocol was registered with the International Prospective Register of Systematic Reviews (PROSPERO) on 26 May 2016 (registration number CRD42016039554).

Publication types

  • Meta-Analysis
  • Research Support, Non-U.S. Gov't
  • Systematic Review

MeSH terms

  • Adolescent
  • Adolescent Nutritional Physiological Phenomena
  • Anemia, Iron-Deficiency / epidemiology
  • Body Composition
  • Child
  • Child Nutritional Physiological Phenomena
  • Child, Preschool
  • Cognition
  • Dairy Products* / analysis
  • Edible Grain* / chemistry
  • Female
  • Food, Fortified* / analysis
  • Hemoglobins / metabolism
  • Humans
  • Male
  • Micronutrients / administration & dosage*
  • Micronutrients / deficiency
  • Prevalence
  • Randomized Controlled Trials as Topic

Substances

  • Hemoglobins
  • Micronutrients

Grants and funding

The study was partially financially supported by the Nestlé Research Center, Lausanne, Switzerland (https://www.nestle.ch/de/nestleschweiz/forschung). Nestlé is a producer of micronutrient fortified milk and cereal products. The funder provided support in the form of salaries for authors [MS] and commented on the final draft of the review protocol and on a draft version of the manuscript, but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The final responsibility was with the corresponding author. The specific roles of the authors are articulated in the ‘author contributions’ section. Additional funding was provided by internal sources of our Institute at the Zurich University of Applied Sciences, Switzerland. There was no additional external funding received for this study.