Diet and genetic factors associated with iron status in middle-aged women.

BACKGROUND

Gene mutations associated with iron overload have been identified. How food and nutrient intakes affect iron status in persons who may be at risk of iron overload because their genetic status is unknown.

OBJECTIVE

The objective was to determine the relation between food and nutrient intakes, HFE genotype, and iron status. Foods and nutrients associated with iron stores, with adjustment for gene mutations associated with hemochromatosis, were explored.

DESIGN

A prospective cohort of women aged 35-69 y (the UK Women's Cohort Study) provided information on diet through a questionnaire and food diary; 6779 women in the cohort provided cheek cell samples, blood samples, or both, which were genotyped for C282Y and H63D mutations, and 2489 women also had their iron status assessed. Relations between serum ferritin and iron intake were investigated by using multiple linear regression, with adjustment for potential confounders.

RESULTS

The strongest dietary association with serum ferritin concentration was a positive association with heme iron and not with nonheme or total iron. Weaker positive associations were seen with red and white meat, and negative associations were seen with total energy and white and brown whole-meal bread, independent of genotype and other potential confounders. The effect of genotype on ferritin concentrations primarily occurred after menopause, at which time a strong interaction between genotype and heme iron intake was observed. Other factors associated with serum ferritin concentrations were age, body mass index, blood donation, menopausal status, and HFE genotype.

CONCLUSIONS

Postmenopausal women eating a diet rich in heme iron and who were C282Y homozygotes had the highest serum ferritin concentrations.