Table 3.

Assessment of validity of included RCTs reporting zinc intake and serum/plasma zinc in children (adapted from the Cochrane Handbook [43]).

Author, Year	Adequate Sequence Generation	Allocation Concealment Adequate	Blinding Adequate	Dropouts Adequate and Outcome Data Complete	Funder Adequate	Lack of other Potential Threats to Validity	Overall Risk of Bias
Mahloudji, 1975 [23]	Unclear	Yes	Unclear	Unclear	Yes	Unclear	High
Hambidge, 1979 [24]	Unclear	Unclear	Yes	Unclear	No	Unclear	High
Walravens, 1983 [25]	Unclear	Yes	Yes	Yes	Yes	Yes	Moderate
Gibson, 1989 [26]	Unclear	Yes	Yes	Yes	No	Yes	High
Cavan, 1993 [27]	Unclear	Yes	Yes	Unclear	Yes	No	High
Friis, 1997 [28]	Unclear	Yes	Yes	Yes	Yes	Yes	High
Rosado, 1997 [29]	Unclear	Yes	Yes	Unclear	Yes	Yes	High
Ruz, 1997 [30]	Unclear	Yes	Yes	Unclear	Yes	Yes	High
Sandstead, 1998 [31]	Unclear	Unclear	Yes	Unclear	No	No	High
Clark, 1999 [32]	Yes	Yes	Yes	Unclear	No	Unclear	High
Smith, 1999 [33]	Unclear	Unclear	Unclear	Yes	Yes	Yes	High
Muñoz, 2000 [34]	Unclear	No	Yes	Yes	Nor	Yes	High
Lopez de Romana, 2005 [35]	Unclear	Unclear	Unclear	Yes	Yes	Yes	High
Silva, 2006 [36]	Unclear	Unclear	No	Yes	No	Yes	High
Sandstead, 2008 [37]	Yes	Yes	Yes	Unclear	No	Yes	Moderate
Wuehler, 2008 [38]	Yes	Unclear	Yes	Yes	Yes	Yes	Low
de Oliveira, 2009 [39]	Unclear	Unclear	No	Unclear	No	Yes	High
Uckarde, 2009 [40]	Unclear	Yes	Yes	Yes	No	Yes	High