Effects of discontinuing coffee intake on iron status of iron-deficient Guatemalan toddlers: a randomized intervention study

Abstract

Coffee is one of the first liquids given to infants in Guatemala. To evaluate whether this practice has an adverse effect on iron status, 160 children 12-24 mo of age who had received coffee for > or = 2 mo and had at least one indicator of iron deficiency were stratified by initial hemoglobin concentration (anemic, or nonanemic, ie, hemoglobin > or = 105 g/L) and randomly assigned to a control (continuation of coffee; coffee) or intervention (provided with a substitute consisting of sugar and coloring; substitute) group for 5 mo. Anemic children were provided with iron supplements for 2-3 mo. Hematologic and anthropometric measurements were made before and after the intervention and dietary and morbidity data were collected every 2 wk. A total of 139 children completed the study: 45 coffee, nonanemic; 56 substitute, nonanemic; 19 coffee, anemic; and 19 substitute, anemic. Compliance with the procedures was good: median coffee intake was 891 mL/wk in the coffee group compared with 18 mL/wk in the substitute group (P = 0.0001). There was no significant effect of discontinuing coffee consumption on changes in hemoglobin, hematocrit, ratio of zinc protoporphyrin to heme or plasma iron, zinc or copper in either nonanemic or anemic children, or plasma ferritin in children who did not take iron supplements. In children who took iron supplements, change in plasma ferritin was significantly greater in the substitute group than in the coffee group (106% compared with 1%, P < 0.05). This implies that coffee interferes with the utilization of supplemental iron. It is likely that the amount and strength of coffee consumed by Guatemalan toddlers are too low to significantly affect the other indexes of iron status.

Effects of discontinuing coffee intake on iron deficient Guatemalan toddlers' cognitive development and sleep

“…We had postulated both a direct effect of coffee on behavior, and an indirect effect through changes in iron status, but neither was found. However, as we report elsewhere, coffee restriction did not affect iron status in these children [35]. Given the absence of an effect of coffee restriction on iron status, these insignificant results are less surprising; removing coffee for 5 months did not affect either iron status or Bayley test scores.…”

“…This association held even controlling for a number of potentially confounding variables. Maternal coffee ingestion was also negatively associated with the child's initial iron status [35]. Similarly, in Costa Rica, coffee intake of mothers during pregnancy was negatively associated with hematological status of the infant at 1 week and 1 month of age [5].…”

“…The study had three additional dependent measures assessed at the beginning and end of the trial: iron status of the child, morbidity, and growth. Results for these three dependent measures have been reported elsewhere [35,36]. This report summarizes the effects of the intervention on children's cognitive development, behavioral responses to the testing situation, and sleep patterns.…”

“…No significant differences between groups in initial food intake or in the change in frequency of consumption of each food type during the intervention were found [35]. There were also no significant differences between Coffee and Substitute groups in initial mean values for Hgb, Hct, ZPP/ H, and ferritin [36].…”

“…Dewey et al [35] found that maternal coffee ingestion during pregnancy was associated with lower iron status (higher levels of ZPP/ H) in the child. Here we examined whether its association with the iron status of the child could explain the association of maternal coffee ingestion during pregnancy with lowered BRS scores.…”