Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: “For the randomisation, the study statistician at UC Davis first stratified the 64 clusters by sub district and union, and then assigned each cluster to 1 of 4 sets containing 16 clusters each”
		Comment: Adequately done
Allocation concealment (selection bias)	Unclear risk	Comment: Insufficient information to permit judgement
Blinding of participants and personnel (performance bias)	High risk	Quote: “It was not possible to blind the women to the type of supplement provided because the supplements were very different in appearance and taste”
		Comment: High risk of bias
Blinding of outcome assessment (detection bias)	Low risk	Quote: “None of the evaluation staff members was involved in supplement delivery”
		“Nonetheless, researchers responsible for the collection of outcome data were kept blind to study assignment”
		Comment: Adequately done
Incomplete outcome data (attrition bias)	High risk	Comment: IFA: 413/2964 × 100 = 13.9% lost to follow‐up
		LNS‐PL: 149/1047 × 100 = 14.2% lost to follow‐up
Selective reporting (reporting bias)	High risk	Comment: Not all outcomes specified in protocol have been reported in the results section (NCT01715038)
Other bias	Low risk	Comment: No other potential sources of bias reported
Was the allocation sequence adequately generated?	Unclear risk
Was the allocation adequately concealed?	Unclear risk
Were baseline outcome measurements similar?	Unclear risk
Were baseline characteristics similar?	Unclear risk
Were incomplete outcome data adequately addressed?	Unclear risk
Was knowledge of the allocated intervention adequately prevented during the study?	Unclear risk
Was the study adequately protected against contamination?	Unclear risk
Was the study free from selective outcome reporting?	Unclear risk
Was the study free from other risk of bias?	Unclear risk