Table 1 Studies reporting candidate biomarkers for cereal food intake
Discriminating metabolites/candidate biomarkers | Dietary factor | Study design | Number of subjects | Analytical method | Sample type | Primary reference(s) |
|---|---|---|---|---|---|---|
Biomarkers of total whole grain (WG) intake | ||||||
 Total ARs | WG products RG products | Intervention study, crossover, randomized (6 weeks) | 30 | GC-MS | Plasma | [30] |
 ARs | WG cereal | Observational study | 33 | GC-MS | Plasma | [55] |
 ARs | WG products RG products | Intervention study, parallel, randomized (12 weeks) | 50 | LC-MS/MS | Plasma | [56] |
 ARs | WG diet RG diet | Intervention study, crossover, randomized (6 weeks) | 33 | LC-MS/MS | Plasma | [57] |
 AR | WG products WG rye WG bread | Observational study | 522 | GC-MS | Plasma | [58] |
 ARs Betaine | WG diet RG diet | Intervention study, crossover, randomized (2 weeks) | 17 | GC-MS/MS (ARs) LC-MS/MS (betaine) | Plasma | [59] |
 Total ARs (C17:0, C19:0, C21:0, C23:0, C25:0) | WG products Habitual diet | Intervention study, parallel, randomized (16 weeks) | 316 | GC-MS | Plasma | [31] |
 Total AR AR (C17:0-C25:0) | WG products | Observational study | 360 | GC-MS | Plasma | [60] |
 AR (C17:0, C19:0, C21:0, C23:0, C25:0) | WG products | Observational study | 407 | LC-MS | Plasma | [61] |
 AR (C17:0-C25:0) | WG products | Observational study | 20 | GC–MS | Adipose tissue | [62] |
 DHBA DHPPA DHBA+DHPPA | WG products Cereal fiber | Observational study | 104 | GC-MS | Urine | [63] |
 DHBA DHPPA Total metabolites | WG foods Cereal fiber | Observational study | 66 | GC-MS | Urine | [64] |
 DHBA DHPPA | WG products Fiber | Observational study | 2833 | HPLC | Plasma | [65] |
 DHPPA | WG products WG rye and wheat | Observational study | 100 | HPLC-CEAD | Urine | [66] |
 2-Aminophenol-Slf HPAA-GlcA HHPAA HMBOA-GlcA HBOA glycoside HPPA HMBOA DHPPA-GlcA 3,5-Dihydroxyphenylethanol-Slf DHPPTA-Slf Hydroxybenzoic acid-Slf Dihydroferulic acid-Slf Enterolactone-GlcA Pyrraline 3-Indolecarboxylic acid-GlcA Riboflavin N-α-Acetylcitrulline 2,8-Dihydroxyquinoline-GlcA | White bread WG bread | Observational study | 155 | HPLC-q-TOF-MS | Urine | [67] |
 5-Nonadecyl-1,3-benzenediol-GlcA (AR) 5-(16-Heneicosenyl)-1,3-benzenediol-GlcA | WG products, fatty fish and bilberries diet WG diet Refined wheat bread diet | Intervention study, parallel, randomized (12 weeks) | 106 | UHPLC-q-TOF-MS | Plasma | [53] |
 Proline Ornithine Arginine | Grain protein-based diet (wheat, bran, rice, and maize) Dairy protein-based diet (milk and milk products, yogurt and cheese) Meat protein-based diet (pork, beef, and chicken) | Intervention study, crossover, randomized (1 week) | 100 | LC-tripleQ-MS | Plasma | [68] |
Biomarkers of whole-grain wheat and rye intake | ||||||
 Total ARs | WG rye bread and WG wheat bread Gluten-free diet | Intervention study, parallel (2 weeks) | 9 | GC-MS | Plasma and erythrocyte membranes | [69] |
 Total ARs | WG rye and wheat Cereal fiber | Observational study | 51 | GC-MS | Plasma | [70] |
 Total ARs AR C17:0, C19:0, C21:0, C23:0, C25:0 Enterolactone | Rye bread Wheat bread | Intervention study, crossover, randomized (8 weeks) | 39 | GC-MS | Plasma | [71] |
 Total AR (C17:0, C19:0, C21:0, C23:0, C25:0) AR C17:0/C21:0 Enterolactone | WG wheat WG rye crisp bread | Intervention study, crossover, randomized (1 week) | 15 | GC-MS | Plasma (AR) erythrocyete membrane (AR) Lipoproteins (AR) Serum (enterolactone) | [69] |
 Total ARs (C17:0–C25:0) AR C17:0/C21:0 | Nordic diet (rich in WG rye and wheat) Control diet | Intervention study, parallel, randomized (18–24 weeks) | 158 | GC-MS | Plasma | [32] |
 Total ARs AR C17:0/C21:0 | WG wheat RG wheat | Intervention study, parallel, randomized (12 weeks) | 72 | LC-MS/MS | Plasma | [72] |
 DHBA DHPPA | Rye bread Bread fiber | Observational study | 122 | HPLC-CEAD | Urine Plasma | [73] |
 DHBA DHPPA | Rye bread with plant sterols Rye bread | Intervention study, parallel, randomized (4 weeks) | 68 | HPLC-CEAD | Plasma | [74] |
 DHBA DHPPA | Rye bread | Intervention study (postprandial trial) | 15 | HPLC-CEAD | Urine | [75] |
 DHBA DHPPA | Rye bread | Intervention study (postprandial trial) | 15 | HPLC-CEAD | Plasma | [76] |
 DHBA DHPPA | Rye | Observational study | 60 | HPLC-CEAD | Urine Plasma | [77] |
 DHBA DHPPA | WG rye and wheat | Observational study | 52 | GC-MS | Urine | [78] |
 DHBA DHBA glycine DHPPA DHPPTA | RG wheat bread, WG wheat bread | Intervention study (postprandial trial) | 12 | LC-MS HPLC-CEAD | Urine | [79] |
 HHPAA-GlcA HHPAA-Slf HPAA-Slf HBOA-GlcA Phenylacetylglutamine derivative Creatinine N-feruloylglycine-Slf | WG rye foods | Intervention study (8 weeks) | 33 | FIE-MS | Urine | [80] |
 DHFA Ferulic acid | WG wheat products Refined wheat products | Intervention study, parallel, randomized (8 weeks) | 80 | HPLC-MS/MS | Urine Serum Feces | [81] |
 3,5-Dihydroxyhydrocinamic acid sulfate Ascorbic acid 2-Aminophenol-Slf Nonanedioic acid DHPPA-GlcA Indolylacryloylglycine Enterolactone-GlcA DHPPA-Slf Ferulic acid-4-Slf 2,4-Dihydroxy-1,4-benzoxazin-3-one-Slf 3,5-Dihydroxyphenylethanol-Slf 1,3,4,5-Tetrahydroxycyclohexane-1-carboxylic acid Others non-identified metabolites | WG rye bread Refined wheat bread | Intervention study, crossover, randomized (4 weeks) | 20 | UPLC-q-TOF-MS | Urine | [50] |
Biomarkers of specific fractions of foods of wheat and rye intake | ||||||
 Total ARs AR (C17:0, C19:0, C21:0, C23:0, C25:0) | WG grains Cereal fiber Bran Total fiber Legume fiber | Observational study | 165 | GC-MS | Plasma | [82] |
 Total ARs AR C17:0/C21:0 | Cereal fiber | Observational study | 2845 | GC-MS | Plasma | [83] |
 Total ARs AR C17:0/C21:0 | Cereal fiber | Observational study | 2744 | GC-MS | Plasma | [84] |
 Total AR AR C17:0/C21:0 | Rye WG/bran Refined wheat | Intervention study, crossover, randomized (6 weeks) | 17 | GC-MS | Plasma | [85] |
 AR C23:0 AR C25:0 AR C17:0/C21:0 | Rye bran flakes | Intervention study (postprandial trial) | 6 | GC-MS | Plasma | [86] |
 ARs (plasma) DHBA (urine) DHPPA (urine) | Cereal fiber | Observational study | 56 | HPLC-CEAD | Urine Plasma | [87] |
 DHBA DHPPA | Cereal fiber | Observational study | 56 | HPLC-CEAD | Plasma | [88] |
 HPAA-Slf HHPAA-Slf | WG sourdough rye bread White bread with native unprocessed rye bran White bread with bioprocessed rye bran White bread | Intervention study, crossover, randomized (postprandial trial) | 12 | LC-q-TOF-MS | Plasma | [52] |
 2,6-dihydroxybenzoic acid 2-aminophenol-Slf | High fiber diet Low fiber diet | Intervention study, crossover, randomized (5 weeks) | 25 | UPLC-q-TOF-MS | Plasma | [89] |
 Ferulic acid | Rye bran bread Inert wheat bran | Intervention study, crossover, randomized (6 weeks) | 18 | HPLC | Urine | [90] |
 Ferulic acid Vanillic acid Sinapic acid 3,4-Dimethoxybenzoic acid Phenylpropionic acid 3-Hydroxyphenylpropionic acid | Whole wheat bread with bioprocessed bran Whole wheat bread with native bran | Intervention study, crossover, randomized (postprandial trial) | 8 | GCxGC-q-TOF-MS | Urine Plasma | [91] |
 Ferulic acid Sinapic acid | White wheat bread with bioprocessed rye bran White wheat bread with native rye bran | Intervention study, crossover, randomized (postprandial trial) | 15 | GC-MS | Urine | [92] |
 Indole-2-carboxylic acid Hydrocinnamic acid α-tocopherol Benzoic acid Cycloartenol Pantothenic acid Phenylacetic acid β-sitosterol | Heat-stabilized rice bran | Intervention study, parallel, randomized (4 weeks) | 7 | GC-MS | Feces | [93] |
Biomarkers of quinoa | ||||||
 Even-numbered AR | Quinoa | Intervention study | NS | LC-MS/MS GC-MS/MS | Plasma | [94] |
Biomarkers dependent on gut microbiota | ||||||
 Enterolactone | High-fiber bread Fiber Fruits and berries | Observational study | 1099 | TRFIA | Plasma | [95] |
 Enterolactone | WG products | Observational study | 1889 | TRFIA | Plasma | [95] |
 Enterolactone | High-fiber rye High-fiber wheat Low-fiber foods | Intervention study, crossover, randomized (4 weeks) | 28 | TRFIA | Plasma | [96] |
 Enterodiol | WG diet RG diet | Intervention study, crossover, randomized (12 weeks) | 13 | HPLC-CEAD) | Urine | [97] |
 Enterolactone Enterodiol | Quinoa flakes Corn flakes | Intervention study, parallel, randomized (4 weeks) | 35 | HPLC | Urine Serum | [98] |
 Enterodiol (serum) Enterolactone (serum & urine) | Flaxseed Rice | Intervention study, parallel (6 weeks) | 27 | HPLC | Urine Serum | [99] |