Dietary intakes of 6–24-month-old urban South Island New Zealand children in relation to biochemical iron status

Abstract

Objective: To investigate food sources and intakes of iron, and dietary factors associated with serum ferritin levels in 6-24-month-old children. Design: A cross-sectional survey employing proportionate cluster sampling was conducted in 1998/1999. Dietary intakes were assessed using a non-consecutive 3-day weighed food record. Serum ferritin and C-reactive protein were analysed from non-fasting venepuncture blood samples and general sociodemographic data were collected. Setting: Cities of Christchurch, Dunedin and Invercargill, New Zealand. Subjects: Randomly selected healthy 6-24-month-old non-breast-feeding children ðn ¼ 226Þ. Results: Total iron intakes (^standard deviation (SD)) among non-breast-feeding infants (,12 months old; n ¼ 42) and toddlers ($12 months old; n ¼ 184) were 8:4^2:9 mg day 21 and 5:0^2:5 mg day 21 ; respectively. Fifteen per cent of infants and 66% of toddlers were at risk of inadequate iron intakes. Main sources of dietary iron were infant formula (60%) for infants and cereals (31%) for toddlers. Meat contributed on average 2% and 10% of dietary iron in the infant and toddler diets, respectively. Dietary factors positively associated with serum ferritin were intakes of iron and vitamin C, whereas intakes of calcium and dietary fibre were negatively associated. For each 1% increase in percentage of energy from iron-fortified formula concomitant with a 1% decrease from dairy products, there was a 4.2% increased odds of replete iron stores (ferritin $20 mg l 21 ). Conclusions: Toddlers were at higher risk of sub-optimal iron intakes than infants. Results suggest that a diet high in bioavailable iron is important for optimising the iron stores of young children in New Zealand.

Iron deficiency and risk factors for lower iron stores in 6–24-month-old New Zealanders

“…Nevertheless, an age-related decline in iron stores in this group of children is consistent with longitudinal and intervention studies, which generally show that ferritin levels decline across the 6-24 month age range when cows' milk or unfortified formula is fed, whereas they remain constant when children consume iron-fortified formula (Fuchs et al, 1993;Michaelsen et al, 1995;Daly et al, 1996;Gill et al, 1997;Oti-Boateng et al, 1998;Morely et al, 1999;Sherriff et al, 1999;Virtanen et al, 2001). It is also consistent with the observed dietary iron intakes in our study which were markedly lower in the 12-24 month than 6-11.9-month-old children (8.4 vs 4.6 mg/day) (Soh et al, 2001). Clearly, there is a need to examine intervention strategies to increase the iron intakes of young New Zealand toddlers to reduce their risks of developing functional iron deficiency.…”

“…Likewise, the higher susceptibility of boys to depleted iron stores compared to girls has been partially attributed, by some investigators, to their more rapid growth rate (Male et al, 2001). In our study and others, dietary factors also apparently played an important role in the determination of ferritin levels, particularly the consumption of cows' milk and iron-fortified formulae (Soh et al, 2001). Certainly, dietary factors accounted for the associaIron deficiency in 6-24-month-old New Zealanders P Soh et al tions found between ferritin and the variables of age and weight-for-age percentiles (Table 4 and Soh et al, 2001).…”

“…These variables were selected based on the literature and our detailed dietary analysis in this group of children (Soh et al, 2001). The latter showed that the consumption of cows' milk and iron-fortified formula was associated with ferritin levels in this group of children, whereas meat intake was not (Soh et al, 2001).…”

“…These variables were selected based on the literature and our detailed dietary analysis in this group of children (Soh et al, 2001). The latter showed that the consumption of cows' milk and iron-fortified formula was associated with ferritin levels in this group of children, whereas meat intake was not (Soh et al, 2001). The variables examined were introduction of cows' milk before 12 months of age, and whether the child was currently consuming iron-fortified formula, had never consumed iron-fortified formula (exclusive breastfed), was currently breastfeeding and was currently consuming on average more than 500 ml of cows' milk per day.…”

“…A nonfasting venipuncture blood sample, anthropometric measurements (length and weight), 3-day weighed food record and pretested general questionnaire (self-administered) were collected during two home visits for each participant. The dietary assessment methods have been described in detail elsewhere (Soh et al, 2001). Ethical approval to conduct the survey was granted by the Ethics Committee of the University of Otago, Dunedin, New Zealand, and written informed consent was obtained from a primary caregiver for each child participating in the survey.…”