Svensson 2004.

Study characteristics
Methods	Design: randomised controlled trial. This study trial led the use of anti‐secretory factor in cereal to prevent mastitis. Setting: Sweden
Participants	Number of participants: (N = 40) postpartum breastfeeding women that had normal deliveries and have healthy full‐term infants, were randomly divided into 2 groups. Participants were breastfeeding or intended to breastfeed. All mothers were Swedish or raised in Sweden. No clear indication of inclusion or exclusion criteria were reported.
Interventions	Number of participants: (N = 40) Intervention group: (N = 20) received hydrothermally processed cereals (HPC) with specific AF‐inducing properties. The cereals of the HPC were treated in a process similar to malting. The content of sugars and amino acids in the cereals at the end of the hydrothermic process has previously been described. After processing, the cereals were dried to 10% moisture. Control group: (N = 20) similar cereal without AF‐inducing properties Participants requested to eat 50 g of cereal every day for a period of 5 weeks. The active material, as well as the placebo food, was available in the form of cereals produced by BioDoc AB, Stockholm, Sweden. Duration of follow‐up 5 weeks
Outcomes	Incidence of mastitis between groups
Notes	No difference between the groups, regarding background, obstetric data, age, education, parity, type of anaesthesia used during the delivery, child sex and birth rate. Loss of participants to follow‐up > 20% Dates of study: data were collected April–August 2002. Funding sources: the authors acknowledged financial support from AS‐Factor AB and the Swedish State under the LUA agreement (grant no. I33913). Declarations of interest: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomly assigned (sealed envelopes that were opened consecutively) to 1 of 2 groups
Allocation concealment (selection bias)	Low risk	Sealed envelopes that were opened consecutively
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Mothers and researchers were blinded.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Researchers were blinded.
Incomplete outcome data (attrition bias) All outcomes	High risk	Differential attrition. The original number of participants in the study was 40. 11 of these participants dropped out in the first 2 weeks. 7 mothers in the experimental group and 3 in the control group. 1 mother was excluded because of incorrect compliance with the intervention. The final number for the experimental group was 12 mothers and 17 for the control group. One of the mothers in the control group failed to provide a milk sample at the end of the study. Final data analysis was on 12 mothers from the experimental group and 17 from the control group.
Selective reporting (reporting bias)	Low risk	Protocol publication was not common practice at the time but there was nothing to indicate evidence of selective reporting.
Other bias	Low risk	No apparent evidence of other bias

AF: anti‐secretory factor
CFU: colony forming unit
HPC: hydrothermically processed cereal
UTI: urinary tract infection