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

BACKGROUND

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

OBJECTIVE

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.

DESIGN

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.

SUBJECTS

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 microg/L, 22-83 (geometric mean, range) and for haemoglobin 132 g/L, 119-148 (arithmetic mean, range), respectively.

RESULTS

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 microg/L (27%) (P < 0.001) and 2 +/- 0.8 g/l (1.5%) (mean +/- SE) (P < 0.05) respectively, after four months of intervention.

CONCLUSIONS

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.