Two years in the making, IZiNCG’s Zinc Fortification Task Force is pleased to share the publication Effects of Foods Fortified with Zinc, Alone or Cofortified with Multiple Micronutrients, on Health and Functional Outcomes: A Systematic Review and Meta-Analysis.
Why zinc fortification
Postharvest food fortification is considered a highly cost-effective intervention to improve dietary intake of micronutrients. As such, many countries with a high burden of zinc deficiency could benefit from including zinc in their mandatory fortification standard.
Why we conducted this review
IZiNCG last reviewed the evidence on zinc fortification in 2009 and concluded that additional information was needed on the efficacy and effectiveness of fortification programs, as only a few studies had found a positive impact on plasma/serum zinc concentrations or functional indicators of zinc status. Although a Cochrane review was conducted in 2016, it was restricted to studies with comparison groups that allowed the independent effect of zinc to be isolated. Posing this condition meant excluding a large body of literature relevant to the “real world” context of large-scale food fortification yet to be synthesized for zinc-related outcomes.
What we found
Our systematic review synthesizes data from 59 studies which assessed biochemical and health outcomes after the provision of a zinc-fortified food or beverage. Fortification vehicles were primarily cereal grains and products, followed by beverages and condiments. The median dose of zinc provided by fortification across studies was 4.4 mg per day, study durations varied from 1 month to 3 years, and 71% of studies were conducted in low- or lower-middle-income countries.
We found that food fortification with zinc, given alone or with other micronutrients, increased plasma/serum zinc concentrations, with a corresponding 24% and 55% decrease in the prevalence of zinc deficiency in efficacy and effectiveness studies, respectively. We also found that fortification with zinc and other micronutrients may increase child weight, reduce episodes of diarrhea and fever and improve cognitive function. However, fewer studies evaluated these latter outcomes and the effects cannot be solely attributed to zinc. We found no adverse outcomes after food fortification with zinc.
Why this matters
Findings from this systematic review show that fortification with zinc, alone or together with other micronutrients, is an efficacious and effective strategy for reducing the prevalence of zinc deficiency in low- and middle-income countries. Globally, nearly 30 countries have mandated the inclusion of zinc in their wheat flour, maize, and/or rice fortification programs. Yet, preliminary analyses show that another 30 countries could benefit from either including zinc in an existing fortification program, or establishing a new fortification program that includes zinc. We hope these findings will encourage more countries whose populations could benefit from zinc fortification to include zinc as a fortificant in an existing or new program.
Zinc Fortification Task Force
The IZiNCG Fortification Task Force is made up of representatives from the IZiNCG Steering Committee, the Food Fortification Initiative, the Global Alliance for Improved Nutrition and Nutrition International.