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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