1 Weight gain during the study (g/kg/day) Show forest plot

1

36

Mean Difference (IV, Fixed, 95% CI)

‐4.1 [‐9.72, 1.52]

2 Increase in length (cm/ 6 days) Show forest plot

1

36

Mean Difference (IV, Fixed, 95% CI)

0.0 [‐0.41, 0.41]

3 Increase in head circumference (cm/ 6 days) Show forest plot

1

36

Mean Difference (IV, Fixed, 95% CI)

0.30 [‐0.11, 0.71]

4 Nitrogen retention (mg/kg/day) Show forest plot

4

Mean Difference (IV, Fixed, 95% CI)

Subtotals only

4.1 All studies

4

95

Mean Difference (IV, Fixed, 95% CI)

31.81 [8.18, 55.43]

4.2 RCTs only

2

39

Mean Difference (IV, Fixed, 95% CI)

51.97 [18.21, 85.73]

4.3 Documented low nitrogen intake

1

10

Mean Difference (IV, Fixed, 95% CI)

36.20 [‐20.90, 93.30]

4.4 Documented lack of tyrosine intake

2

56

Mean Difference (IV, Fixed, 95% CI)

24.54 [‐1.56, 50.65]

4.5 No documented low intake of other nutrients

2

39

Mean Difference (IV, Fixed, 95% CI)

64.64 [9.12, 120.16]

4.6 Preterm only

4

73

Mean Difference (IV, Fixed, 95% CI)

40.53 [13.52, 67.55]

4.7 Full‐term only

1

16

Mean Difference (IV, Fixed, 95% CI)

‐14.0 [‐79.24, 51.24]

5 Plasma level of free cyst(e)ine (micromoles/100 ml) Show forest plot

4

WMD (Fixed, 95% CI)

Subtotals only

5.1 All studies

4

112

WMD (Fixed, 95% CI)

2.48 [1.44, 3.53]

5.2 RCTs only

2

56

WMD (Fixed, 95% CI)

2.21 [0.86, 3.57]

5.3 Document low nitrogen intake

1

10

WMD (Fixed, 95% CI)

6.88 [1.58, 12.18]

5.4 Documented lack of tyrosine intake

2

56

WMD (Fixed, 95% CI)

3.19 [1.50, 4.88]

5.5 No documented low intake of other nutrients

2

56

WMD (Fixed, 95% CI)

2.05 [0.72, 3.38]

5.6 Preterm only

4

90

WMD (Fixed, 95% CI)

2.46 [1.28, 3.64]

5.7 Full‐term only

1

16

WMD (Fixed, 95% CI)

1.79 [‐1.76, 5.34]

6 Total plasma cyst(e)ine level (micromoles/ 100 ml) Show forest plot

1

20

Mean Difference (IV, Fixed, 95% CI)

9.40 [5.13, 13.67]

1 Weight gain during the study (g/kg/day) Show forest plot

1

332

Mean Difference (IV, Fixed, 95% CI)

0.25 [‐2.70, 3.20]

2 Weight (g) at 36 weeks of postmenstrual age Show forest plot

1

323

Mean Difference (IV, Fixed, 95% CI)

‐4.80 [‐90.66, 81.06]

3 Death by 36 weeks of postmenstrual age Show forest plot

1

391

Risk Ratio (M‐H, Fixed, 95% CI)

1.23 [0.78, 1.95]

4 Bronchopulmonary dysplasia among survivors at 36 weeks of postmenstrual age Show forest plot

1

328

Risk Ratio (M‐H, Fixed, 95% CI)

0.99 [0.76, 1.29]

5 Death or Bronchopulmonary Dysplasia (36 weeks postmenstrual age) Show forest plot

1

391

Risk Ratio (M‐H, Fixed, 95% CI)

1.04 [0.85, 1.27]

6 Retinopathy of prematurity (any stage) among those examined Show forest plot

1

332

Risk Ratio (M‐H, Fixed, 95% CI)

0.89 [0.71, 1.12]

7 Severe (stage 3 or more) retinopathy of prematurity among those examined Show forest plot

1

332

Risk Ratio (M‐H, Fixed, 95% CI)

1.06 [0.59, 1.90]

8 Necrotizing enterocolitis (operated) Show forest plot

1

391

Risk Ratio (M‐H, Fixed, 95% CI)

1.08 [0.56, 2.07]

9 Periventricular leukomalacia in all examined Show forest plot

1

388

Risk Ratio (M‐H, Fixed, 95% CI)

0.72 [0.38, 1.36]

10 Intraventricular hemorrhage (any grade) Show forest plot

1

388

Risk Ratio (M‐H, Fixed, 95% CI)

1.10 [0.78, 1.55]

11 Severe intraventricular hemorrhage (grade 3‐4) Show forest plot

1

386

Risk Ratio (M‐H, Fixed, 95% CI)

1.18 [0.66, 2.11]

12 Plasma level of free cyst(e)ine (micromoles/ 100 ml) Show forest plot

1

165

Mean Difference (IV, Fixed, 95% CI)

‐2.50 [‐4.61, ‐0.39]