Abrams et al. (2005)
Reason for exclusion	Intervention given was prebiotic (inulin‐type fructans)
Ahmed et al. (2005)
Reason for exclusion	Participants were anaemic at baseline and the intervention was therapeutic
Ahmed et al. (2010)
Reason for exclusion	Participants were anaemic at baseline and the intervention was therapeutic
Angeles‐Agdeppa et al. (1997)
Reason for exclusion	Participants were asymptomatic anaemic individuals. Intervention was used as therapeutic intervention
Beasley et al. (2000)
Reason for exclusion	Participants were infected with schistosomiasis. Infection is believed to affect the outcome. IFA taken as therapeutic intervention
Castillo‐Durán et al. (2001)
Reason for exclusion	The study was from non‐LMIC country
Chan et al. (2006)
Reason for exclusion	The study was carried out in a non LMIC country
Damsgaard et al. (2012)
Reason for exclusion	The study included overweight individuals and was also conducted in a non‐LMIC country
De Oliveiera 2009
Reason for exclusion	The study was from non‐LMIC country
Deshmukh et al. (2008)
Reason for exclusion	This study did not have an appropriate control group
Diogenes et al. (2013)
Reason for exclusion	The study was from non‐LMIC country
Dongre et al. (2011)
Reason for exclusion	This study did not have an appropriate control group
Eftekhari et al. (2006)
Reason for exclusion	Participants were iron deficient at baseline and the intervention was therapeutic
Friis et al. (1997)
Reason for exclusion	93% of the Participants were infected by schistosomiasis. Infection is believed to affect the outcome
Ganmaa et al. (2017)
Reason for exclusion	Participants were asymptomatic vitamin D deficient individuals according to the inclusion criteria. Intervention was used as therapeutic intervention
Ilich‐Ernst et al. (1998)
Reason for exclusion	The study was carried out in a non LMIC Country
Kianfar et al. (2000)
Reason for exclusion	The intervention was therapeutic
Kotecha et al. (2009)
Reason for exclusion	The study does not have an appropriate control group
Lambert et al. (2008)
Reason for exclusion	The study was carried out in a non LMIC Country
Ma et al. (2014)
Reason for exclusion	The study does not have an appropriate control group
Manger et al. (2008)
Reason for exclusion	The study population included children and adolescents and the study author suggested that the data for the adolescent subgroup was too small
Mann et al. (2002)
Reason for exclusion	Participants were asymptomatic anaemic individuals. Grouping was done based on energy intakes
McKenna et al. (1997)
Reason for exclusion	The study was carried out in a non LMIC Country
Mwaniki et al. (2002)
Reason for exclusion	The intervention was therapeutic
Pilz et al. (2017)
Reason for exclusion	The methods describe inclusion criteria of age 18–45 years but results show age of participants was between 22 and 29 years. Participants are not adolescents
Prentice et al. (2005)
Reason for exclusion	The study was carried out in a non LMIC Country
Prentice et al. (2012)
Reason for exclusion	The study population included children and adolescents. The corresponding authors were contacted for the adolescent subgroup data; however we did not receive any response
Rerksuppaphol and Rerksuppaphol (2016)
Reason for exclusion	The study population included children and adolescents. The corresponding authors were contacted for the adolescent subgroup data; however we did not receive any response
Rousham et al. (2013)
Reason for exclusion	Intervention was used as therapeutic intervention
Sarma et al. 2006)
Reason for exclusion	The study population included children and adolescents. The corresponding authors were contacted for the adolescent subgroup data; however we did not receive any response
Schou et al. (2003)
Reason for exclusion	The study was carried out in a non LMIC Country
Shah and Gupta (2002)
Reason for exclusion	Intervention was used as therapeutic intervention
Silk et al. 2015)
Reason for exclusion	The study was carried out in a non LMIC Country
Sunawang et al. (2009)
Reason for exclusion	The participants were not adolescents
Tee et al. (1999)
Reason for exclusion	There is no appropriate control group
Viljakainen et al. (2006)
Reason for exclusion	The study was carried out in a non LMIC Country
White et al. (2015)
Reason for exclusion	The study was carried out in a non LMIC Country
Yusoff et al. (2012)
Reason for exclusion	The study was from non‐LMIC country