TABLE 1.

Summary of participants, interventions, comparisons, outcomes, and study design criteria used for the inclusion and exclusion of studies

	Inclusion	Exclusion
Participants	Healthy	Existing disease
	Adults (≥18 y)	Children (<18 y)
	Female and/or male participants	Pregnant
Interventions	Isolation of blood cell type from zinc supplemented/depleted subjects	No intervention
		Commercial cell line or isolation of blood cell type and treatment/depletion of zinc in vitro
Comparisons	Baseline
	Placebo
Outcomes	Expression of metallothionein
	Expression of zinc transporter(s)
Study design	No restriction