Zinc-biofortified staple food crops to improve zinc status in humans: a systematic review

Abstract

Biofortified foods are a new approach to increase minerals in the diet, and evidence suggests that zinc (Zn) biofortification can improve Zn physiological status in humans. This systematic review aimed to answer the question: "What are the effects of the consumption of Zn biofortified foods on Zn status in humans?". This review was conducted according to PRISMA guidelines and registered in PROSPERO (CRD42021250566). PubMed, Cochrane, Scopus and Science Direct databases were searched for studies that evaluated the effects of Zn biofortified foods on Zn absorption. Of 4282 articles identified, nine remained after inclusion/exclusion criteria were applied. Limitations in study quality, external and internal validity (bias/confounding), and study power were evaluated. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) was used to assess the certainty of evidence. Of the nine articles included, five observed an increase in total Zn absorption, and one showed that Zn participated in the conversion of linoleic acid to dihomo-γ-linolenic acid. By increasing the amount of Zn in the food, Zn biofortification can reduce the phytate:Zn molar ratio and improve Zn absorption in humans. More studies are needed to clarify what portion of Zn biofortified foods/day is needed to achieve a significant effect on Zn status.

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Disclosure statement

The authors declare no conflict of interest.

Data availability statement

The authors confirm that the data supporting the findings of this study are available within the following articles [and/or] its supplementary materials: Ahsin et al. (2020), Signorell et al. (2019), Sazawal et al. (2018), Liong et al. (2021), Chomba et al. (2015), Islam et al. (2013), Kodkany et al. (2013), Rosado et al. (2009), and Donangelo et al. (2003).

Additional information

Funding

The authors would like to thank the National Council for Scientific and Technological Development (CNPq), the Coordination for the Improvement of Higher Education Personnel (CAPES), and the Minas Gerais State Research Support Foundation (FAPEMIG). The first author is grateful to the Fulbright Commission Brazil for the grant (2020–2021) that supported her research in the United States, and she thanks the Food Science Department at the Cornell University for providing facilities during her split Ph.D. in the United States.