title: Blackcurrant seed press residue increases tocopherol concentrations in serum and stool whilst biomarkers in stool and urine indicate increased oxidative stress in human subjects.
abstract: Berry seeds are a tocopherol-rich by-product of fruit processing without specific commercial value. In a human intervention study, the physiological impact of blackcurrant seed press residue (PR) was tested. Thirty-six women (aged 24 +/- 3 years; twenty non-smokers, sixteen smokers) consumed 250 g bread/d containing 8% PR for a period of 4 weeks (period 3). Comparatively, a control bread without PR (250 g/d) was tested (period 2) and baseline data were obtained (period 1). Blood, stool and 24 h urine were collected during a 5 d standardised diet within each period. Tocopherol and Fe intakes were calculated from food intake. In serum, tocopherol concentration and Fe parameters were determined. In urine, oxidative stress markers 8-oxo-2'-deoxyguanosine, 8-iso-PGF2alpha and inflammatory response marker 15-keto-dihydro-PGF2alpha were analysed. Stool tocopherol concentration, genotoxicity of faecal water (comet assay) and antioxidant capacity of stool (aromatic hydroxylation of salicylic acid) were determined. Fe and total tocopherol intake, total tocopherol concentrations in serum and stool, and genotoxicity of faecal water increased with PR bread consumption (P < 0.05). The antioxidant capacity of stool decreased between baseline and intervention, expressed by increased formation of 2,3- and 2,5-dihydroxybenzoic acid in vitro (P < 0.05). In smokers, 8-oxo-2'-deoxyguanosine increased with PR consumption (P < 0.05). Prostane concentrations were unaffected by PR bread consumption. In summary, the intake of bread containing blackcurrant PR for 4 weeks increased serum and stool total tocopherol concentrations. However, various biomarkers indicated increased oxidative stress, suggesting that consumption of ground berry seed may not be of advantage.
authors.affiliation: Department of Nutritional Physiology, Friedrich Schiller University of Jena, Dornburger Strasse 24-29, D-07743 Jena, Germany.
authors.forename: Dorit
authors.initials: D
authors.lastname: Helbig
authors.forename: Andreas
authors.initials: A
authors.lastname: Wagner
authors.forename: Michael
authors.initials: M
authors.lastname: Glei
authors.forename: Samar
authors.initials: S
authors.lastname: Basu
authors.forename: Rainer
authors.initials: R
authors.lastname: Schubert
authors.forename: Gerhard
authors.initials: G
authors.lastname: Jahreis
mesh_terms: D000080242:8-Hydroxy-2'-Deoxyguanosine; D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D000975:Antioxidants / Q000737:chemistry; D015415:Biomarkers / Q000032:analysis / Q000652:urine; D001939:Bread; D016022:Case-Control Studies; D020552:Comet Assay; D003849:Deoxyguanosine / Q000031:analogs & derivatives / Q000032:analysis; D015237:Dinoprost / Q000031:analogs & derivatives / Q000032:analysis; D002149:Energy Intake; D005243:Feces / Q000737:chemistry; D005260:Female; D006147:Guanine / Q000031:analogs & derivatives / Q000032:analysis; D019073:HT29 Cells; D006801:Humans; D007501:Iron / Q000652:urine; D018384:Oxidative Stress; D010936:Plant Extracts / Q000008:administration & dosage*; D031965:Ribes; D012639:Seeds; D012907:Smoking; D024505:Tocopherols / Q000032:analysis / Q000097:blood*; D055815:Young Adult
chemical_list: D000975:Antioxidants; D015415:Biomarkers; D010936:Plant Extracts; C008228:15-keto-13,14-dihydroprostaglandin F2alpha; C075750:8-epi-prostaglandin F2alpha; C024829:8-hydroxyguanine; D006147:Guanine; D000080242:8-Hydroxy-2'-Deoxyguanosine; D015237:Dinoprost; D007501:Iron; D003849:Deoxyguanosine; D024505:Tocopherols