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Table 3 Systematic review results and key outcomes on differences in nutrient status between PKU patients and healthy controls

From: Status of nutrients important in brain function in phenylketonuria: a systematic review and meta-analysis

Nutrient

Number of publications

Number of subjects from retrieved publications

Studies reporting significantly lower levels in PKU compared to controls

Studies reporting significantly higher levels in PKU compared to controls

Studies reporting no significant difference between PKU and controls

PKU

Controls

DHAa, b

16

479

586

9 studies [5, 32, 111,112,113,114,115,116,117]

–

6 studies [52,53,54, 118,119,120]

EPAc

14

397

513

5 studies [5, 32, 112, 114, 117]

–

8 studies [52,53,54, 111, 113, 115, 119, 120]

Choline

2

24

41

1 study [33]

–

1 study [98]

Cholesterold

18

727

837

12 studies [55, 61, 107, 111, 121,122,123,124,125,126,127,128]

–

6 studies [53, 86, 112, 119, 129, 130]

Uridine

0

–

–

–

–

–

PL

2

26

22

1 study [34]

–

1 study [112]

Vitamin A

3

191

190

–

–

3 studies [44, 131, 132]

Vitamin Ed

7

339

346

1 study [131]

1 study [126]

5 studies [30, 35, 37, 44, 132]

Vitamin Cd

3

138

168

–

1 study [132]

2 studies [44, 126]

Selenium

16

666

618

14 studies [6, 30, 35, 44, 67, 69,70,71,72,73, 132,133,134,135]

–

2 studies [37, 45]

Vitamin B6d

2

89

56

1 study [136]

1 study [137]

–

Vitamin B12d

6

307

1883

1 study [136]

3 studies [85, 119, 138]

2 studies [88, 89]

Folic acidd

7

306

1817

1 study [136]

5 studies [85, 87,88,89, 138]

1 study [86]

Calciumd

11

373

610

2 studies [76, 133]

1 study [139]

8 studies [77, 78, 119, 125, 127, 132, 135, 140]

Vitamin Dc

6

171

310

3 studies [55, 130, 140]

–

2 studies [76, 139]

Magnesiumd

8

288

541

3 studies [76, 77, 133]

1 study [139]

4 studies [78, 125, 132, 135]

Zincc, d

8

286

345

2 studies [132, 133]

–

5 studies [71, 72, 76, 125, 135]

Ironc, d

10

420

383

1 study [132]

1 study [119]

7 studies [71, 127, 128, 133, 135, 141, 142]

Iodine

0

–

–

–

–

–

  1. Notes: aAll DHA significance levels are for total plasma lipids or plasma phospholipids except for [53, 54] which reported erythrocyte lipid levels
  2. bFor [143], the statistical significance of a stated lower DHA level was not reported, therefore this study was not included in the outcomes above
  3. cDiffering findings for sub-grouped PKU only patients compared to controls reported for EPA [118], zinc [144], iron [145] and vitamin D [77]. These data are not included in this table. The data for all PKU patients from these publications were pooled for the meta-analysis
  4. dFor all studies by Schulpis et al. [124,125,126,127,128, 136], the PKU group was sub-grouped into well controlled PKU and poorly controlled PKU. Differences between well-controlled PKU and healthy controls only are reported in this table. The data for both groups of PKU patients were pooled for the meta-analysis
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Orphanet Journal of Rare Diseases

ISSN: 1750-1172