A decrease in iron status in young healthy women after long–term daily consumption of the recommended intake of fibre–rich wheat bread



Fibrerich bread and cereals are included in the recommendations of a healthy diet.


To measure the effects of long–term consumption of the recommended intake of fibre–rich wheat bread on the iron status of young healthy women with adequate iron stores.


Four–months intervention study including healthy female subjects assigned into two groups provided daily with 300 g of fibre–rich wheat bread, prepared with or without phytase as a supplement to their habitual diet.


Forty–one women aged 24.8 ± 3.8 years (mean ± SD) and an average BMI of 22.0 ± 2.9 kg/m2 participated. Baseline values for serum ferritin were 45 µg/L, 22–83 (geometric mean, range) and for haemoglobin 132 g/L, 119–148 (arithmetic mean, range), respectively.


Distribution of energy intake from protein, fat and carbohydrate, and daily intake of dietary fibre and iron were similar in the two groups and within the recommended levels. There was no effect of the phytase added to the wheat bread on the iron status of the subjects, but an effect of the intervention period. Serum ferritin and haemoglobin levels were significantly reduced by 12 ± 1.1 µg/L (27%) (P < 0.001) and 2 ± 0.8 g/l (1.5%) (mean ± SE) (P < 0.05) respectively, after four months of intervention.


The present long–term study indicates that consumption of the recommended daily intake of fibre–rich wheat bread results in an impairment of iron status in women with initially sufficient iron stores. Reduction of the phytic acid concentration in the bread was not sufficient to maintain iron status.

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Nordic Nutrition Recommendations


Phytase unit

IP6 :

Inositol hexaphosphates

IP5 :

Inositol pentaphosphates

IP4 :

Inositol tetraphosphates

IP3 :

Inositol triphosphates


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Corresponding author

Correspondence to M. Bach Kristensen.

Additional information

Contributors: ABAJ, ADT, BS and MH co–developed the study design. ABAJ was involved in the subject recruitment and data collection under the supervision of MH. All authors were involved in the interpretation of the results. MBK, IT and MH wrote the first draft. MBK and IT co–refined it into the final draft after contributions from all authors.

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Bach Kristensen, M., Tetens, I., Alstrup Jørgensen, A.B. et al. A decrease in iron status in young healthy women after long–term daily consumption of the recommended intake of fibre–rich wheat bread. Eur J Nutr 44, 334–340 (2005). https://doi.org/10.1007/s00394-004-0529-4

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Key words

  • hamoglobin
  • serum ferritin
  • phytic acid
  • dietary fibre
  • wheat bran