Introduction
Materials and methods
Human iron absorption from lactic-fermented vegetables
Subjects
Lactic fermentation
Test meals
Oral reference dose
Iron absorption measurements
Human zinc absorption from lactic-fermented vegetables
Subjects
Test meals
Zinc absorption measurements
Analysis of mineral, phytate, and organic acid content in the test meals
Lactate and fermented vegetable experiments in the Caco-2/HepG2 cell system
Sample preparation
Cell lines and set-up of the cell model
Cell experiments including hepcidin, ferritin, and total protein analysis
Lactate experiments in mono-cultured Caco-2 cells
Cell line
Lactate and iron uptake experiments
Analysis of Fe3+ and Fe2+ using differential pulse anodic stripping voltammetry (DPASV)
Statistics
Results
Lactic-fermented vegetables added to a meal increased iron but not zinc absorption in humans
Meal |
n
| Non-heme iron content mg/serving (240 g) | Absorption % | Individual absorptiond A40 % | Mean of individual absorption ratio F:Ce
| Myo-inositol hexaphosphate μmol/serving (mg phytate-P) | ||
---|---|---|---|---|---|---|---|---|
Meal | Ref. dose | Mean | SEM | |||||
Low-phytate meal | ||||||||
White wheat rollsa,f + fresh vegetablesb
| 8 | 4.4 | 9.5 | 25.0 | 13.6± | 1.6 | 1.78 ± 0.10 | 6.1 (1.1) |
White wheat rollsa,f + fermented vegetablesb,f
| 8 | 4.4 | 15.6 | 25.0 | 23.6± | 2.0 | 2.5 (0.5) | |
High-phytate meal | ||||||||
Wheat bran rollsc,f + fresh vegetablesb,f
| 9 | 4.0 | 4.6 | 36.8 | 5.2± | 0.8 | 2.07 ± 0.16 | 159.2 (29.6) |
Wheat bran rollsc,f + fermented vegetablesb,f
| 9 | 4.0 | 8.8 | 35.8 | 10.4± | 2.4 | 155.6 (28.9) |
Meal All meals incl. 50 g cottage cheese |
n
| Zinc content μmol/serving | Zinc absorption % | Absorption ratio F:Cd
| Myo-inositol hexaphosphate μmol/serving (mg phytate-P) | |
---|---|---|---|---|---|---|
Mean | SD | |||||
Low-phytate meal | ||||||
White wheat rollsa,e + fresh vegetablesb,e
| 8 | 17.1 | 42.3 ± | 8.6 | 1.09 ± 1.16 | 13.5 (2.5) |
White wheat rollsa,e + fermented vegetablesb,e
| 8 | 15.6 | 46.1 ± | 10.0 | 6.3 (1.2) | |
High-phytate meal | ||||||
Wholemeal wheat rollsc,e + fresh vegetablesb
| 6 | 31.1 | 12.9 ± | 3.5 | 1.04 ± 0.27 | 363.8 (67.6) |
Wholemeal wheat rollsc,e + fermented vegetablesb
| 6 | 32.4 | 13.4 ± | 1.6 | 356.6 (66.3) |
Composition of test meals
Food sample | Ca mmol | Zn μmol | Fe μmol | Myo-inositol hexaphosphate μmol (mg phytate-P) |
---|---|---|---|---|
Fresh vegetablesa
| 0.8 | 4.1 | 3.9 | 4.4 (0.8) |
Fermented vegetablesb
| 0.5 | 3.2 | 3.1 | n. d. |
Test meals iron absorption | ||||
White wheat rolls | n. m. | 8.4 | 68.0 | 1.2 (0.2) |
Wheat bran rolls | n. m. | 14.8 | 68.0 | 110.6 (20.5) |
Test meals zinc absorption | ||||
White wheat rolls | 0.6 | 8.0 | 75.8 | 4.7 (0.9) |
Wholemeal wheat rolls | 0.8 | 24.0 | 38.0 | 355.0 (66.0) |
Cottage cheese | 1.0 | 5.4 | 1.8 | – |