Putet 1987.

Study characteristics
Methods	Parallel randomised controlled trial, single centre
Participants	Inclusion criteria: VLBW boys of appropriate weight for gestational age and no infant had medical problems at the time of the study Exclusion criteria: not stated Setting: not stated Timing: not stated
Interventions	Cow's milk casein hydrolysate (1 g per 100 mL) added to pooled human milk (8 infants) versus unsupplemented pooled human milk (8 infants). Duration of intervention was not clear.
Outcomes	Primary: not specified as primary and secondary outcomes, but short‐term growth parameters were assessed, including weight, length, head circumference. Total serum protein, BUN, acid‐base status, free amino acids, nitrogen retention, bicarbonate level, oxygen consumption, and energy expenditures were also assessed.
Notes	Conflicts of interest: no details Source of funding: supported by a grant from University Claude Bernard (Lyon) and by an INSERM Contract (PRC 123.0228)
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No details
Allocation concealment (selection bias)	Unclear risk	No details
Blinding (performance bias and detection bias) All outcomes	Unclear risk	No details
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No details
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	No details
Selective reporting (reporting bias)	Low risk	The protocol was not available, but it appeared that all pre‐specified outcomes were measured and reported.
Other bias	Low risk	No other apparent sources of bias related to the study design noted. No extreme baseline imbalances observed.