TABLE 3.
Summary of reliability studies on biomarkers of polyphenol consumption1
| Biomarker2 | Biofluid | No. of subjects | Country | Period of sample collection | No. of samples | ICC coefficient3 | Ref |
| Flavanols | |||||||
| Gallocatechin | Plasma (fasting) | 7 | Germany | 4 wk | 3 | 0.60 | (116) |
| Quercetin | Plasma (fasting) | 7 | Germany | 4 wk | 3 | 0.79 | (116) |
| Quercetin | Urine (24-h) | 154 | France | 4 d | 3–4 | 0.61 | (117) |
| Kaempferol | Plasma (fasting) | 7 | Germany | 4 wk | 3 | 0.78 | (116) |
| Kaempferol | Urine (24-h) | 154 | France | 4 d | 3–4 | 0.54 | (117) |
| Isorhamnetin | Plasma (fasting) | 7 | Germany | 4 wk | 3 | 0.68 | (116) |
| Isorhamnetin | Urine (24-h) | 154 | France | 4 d | 3–4 | 0.59 | (117) |
| Flavones | |||||||
| Luteolin | Plasma (fasting) | 7 | Germany | 4 wk | 3 | 0.67 | (116) |
| Flavanones | |||||||
| Hesperetin | Plasma (fasting) | 7 | Germany | 4 wk | 3 | 0.65 | (116) |
| Hesperetin | Urine (24-h) | 154 | France | 4 d | 3–4 | 0.57 | (117) |
| Naringenin | Urine (24-h) | 154 | France | 4 d | 3–4 | 0.58 | (117) |
| Isoflavones | |||||||
| Daidzein | Plasma (nonfasting) | 40 | USA | 2–3 y | 2 | 0.00 | (118) |
| Daidzein | Urine (24-h) | 45 | USA | 2–3 y | 2 | 0.00 | (118) |
| Genistein | Plasma (nonfasting) | 40 | USA | 2–3 y | 2 | 0.03 | (118) |
| Genistein | Urine (24-h) | 45 | USA | 2–3 y | 2 | 0.02 | (118) |
| Equol | Plasma (nonfasting) | 40 | USA | 2–3 y | 2 | 0.00 | (118) |
| Equol | Urine (24-h) | 45 | USA | 2–3 y | 2 | 0.09 | (118) |
| Lignans | |||||||
| Enterolactone | Plasma (nonfasting) | 40 | USA | 2–3 y | 2 | 0.44 | (118) |
| Enterolactone | Urine (24-h) | 45 | USA | 2–3 y | 2 | 0.52 | (118) |
| Enterolactone | Plasma (fasting) | 7 | Germany | 4 wk | 3 | 0.70 | (116) |
| Enterolactone | Urine (24-h) | 154 | France | 4 d | 3–4 | 0.65 | (117) |
| Enterodiol | Urine (24-h) | 154 | France | 4 d | 3–4 | 0.57 | (117) |
| Alkylresorcinols | |||||||
| Total alkylresorcinols | Plasma (fasting) | 18 | Sweden | 3 d | 3 | 0.60 | (91) |
| Total alkylresorcinols | Plasma (nonfasting) | 18 | Sweden | 3 d | 3 | 0.18 | (91) |
| Phenolic acids | |||||||
| Caffeic acid | Plasma (fasting) | 7 | Germany | 4 wk | 3 | 0.61 | (116) |
| Caffeic acid | Urine (24-h) | 154 | France | 4 d | 3–4 | 0.58 | (117) |
| Chlorogenic acid | Urine (24-h) | 154 | France | 4 d | 3–4 | 0.64 | (117) |
| Ferulic acid | Plasma (fasting) | 7 | Germany | 4 wk | 3 | 0.76 | (116) |
| p-Coumaric acid | Plasma (fasting) | 7 | Germany | 4 wk | 3 | 0.67 | (116) |
| m-Coumaric acid | Urine (24-h) | 154 | France | 4 d | 3–4 | 0.54 | (117) |
| Gallic acid | Urine (24-h) | 154 | France | 4 d | 3–4 | 0.59 | (117) |
| 4-O-Methylgallic acid | Urine (24-h) | 154 | France | 4 d | 3–4 | 0.48 | (117) |
| Ellagic acid | Plasma (fasting) | 7 | Germany | 4 wk | 3 | 0.73 | (116) |
| Dihydrochalcones | |||||||
| Phloretin | Urine (24-h) | 154 | France | 4 d | 3–4 | 0.48 | (117) |
1
ICC, intraclass correlation; Ref, reference.
2
Biomarkers were measured after deconjugation of glucuronides and sulfate esters with glucuronidases and sulfatases, respectively.
3
ICC coefficients describe the reliability of biomarkers and are defined as the proportion of variance between and within individuals.