Table 1 Characteristics of included trials

B LACTIS

Barclay 2003 (Italy) [4] plus unpublished data

Healthy term newborns, ≤ 28 d of life at enrollment;

Bb12 (3 × 10⁷ CFU) in reduced protein (1.8 g/100 kcal) IF (n = 29/53)

Reduced protein (1.8 g/100 kcal) IF (n = 27/58)

4 mo (4 mo)

BW 2500 to 4200 g

Gibson 2009 (Australia) [7]

≥37 wk gestation, BW 2500–4500 g, ≤10 d

Bb12 (3.85 × 10⁸ CFU/100 kcal + LCPUFA in reduced protein IF (1.8 g protein/100 kcal) (n = 62/72)

Standard IF (n = 62/70)

7 mo (7 mo)

Holscher 2012 (USA) [8]

Healthy term infants (7 wk)

Bb12 (10 ⁶ CFU/g) in pHF 100% whey (2.2 g protein/100 kcal) (n = 41/50)

pHF 100% whey (n = 34/43)

6 wk (6 wk)

Urban 2008 (South Africa) [5] plus unpublished data

Healthy term infants born to HIV-infected mothers (≤ 1 wk)

Bb12 (? CFU-no data) in acidified IF (2 g protein/100 kcal) (n = 29/45*)

Acidified IF (n = 28/43*)

119 d (182 d)

Velaphi 2008 (South Africa) [9]

Healthy term infants born from HIV(+) mothers (≤1 wk)

Bb12** (? CFU-no data) in chemically acidified IF (2 g protein/100 kcal) (n = 31/53*)

Chemically acidified IF (n = 34/51*)

6 mo (182 d)

Weizman 2006 (Israel) [3]

Healthy term infants <4 mo

Bb12 (1 × 10⁷ CFU/g) in IF (2.2 g protein/100 kcal) (n = 20)

Standard IF (n = 19)

4 wk (4 wk)

Ziegler 2003 (Germany) [10]

Healthy term infants (6–10 d)

Bb12 (3.6 × 10⁹ CFU /g) in reduced protein (1.9 g/100 kcal) 100% whey pHF (n = 28/40)

Reduced protein, 100% whey pHF (n = 27/40)

4 mo (112 d)

LACTOBACILLUS GG

Scalabrin 2009 (USA) [12]

Healthy term infants (14 d)

LGG (10⁸ CFU/g) in EH casein formula (n = 63/94)

EH casein formula (n = 70/94)

120 d/150 d in a subgroup

Vendt 2006 (Estonia & Finland) [11]

Healthy term infants (≤2 mo)

LGG (10⁷ CFU/g) in IF (n = 51/60)

IF (n = 54/60)

6 mo (6 mo)