Iron intake and iron status among adults in the Netherlands

To assess the adequacy of iron intake and status, the prevalence of marginal iron status, the physiological and lifestyle factors influencing iron status and the role of dietary factors affecting the bioavailability of iron among Dutch adults.

Food consumption was measured with 3 d diet records. Iron status and prevalence of iron deficiency and iron accumulation were evaluated using different criteria. Physical, biochemical and lifestyle characteristics were determined and relationships with iron status were evaluated by bi- and multivariate regression analysis.

A sample of 444 adults, aged 20-79 y stratified for sex and 10 y age classes, with an overrepresentation of people with a low habitual intake of vitamin B6.

Average iron intake was higher than the recommended daily allowance for the Netherlands in all sex-age groups except women aged 20-49, in which group average iron intake was 23% below the recommendation. Early iron deficiency, as reflected in low ferritin levels, was not found among men aged 20-49, but was observed in 5% of women aged 50-79, 11% of men aged 50-79, and 16% of women aged 20-49. Iron deficiency anaemia as reflected in low haemoglobin levels was found in 0-5% of the age-sex groups. Among men and women, 16% and 13% of variance in haemoglobin level, respectively, could be explained by physiological and dietary factors. For ferritin, the proportions were 36% and 34%, respectively. Iron status was correlated negatively with the vegetable fraction of the diet, and positively with factors from the animal fraction (haem iron, animal protein, meat). Further, haemoglobin was positively correlated with body weight among men, and with both age and use of oral contraceptives among women. Both among men and women, blood donorship in the six months prior to the study was negatively associated with serum ferritin levels.

Women aged 20-49 are the adult sex-age group with the greatest risk of developing (an early stage of) iron depletion. The most important dietary factors influencing the iron status are the type of iron (haem/non-haem) and factors affecting the bioavailability of iron.