Alida Melse-Boonstra

Sharply higher rates of iron deficiency in obese Mexican women and children are predicted by obesity-related inflammation rather than by differences in dietary iron intake

BACKGROUND Obese individuals may be at increased risk of iron deficiency (ID), but it is unclear whether this is due to poor dietary iron intakes or to adiposity-related inflammation. OBJECTIVE The aim of this study was to examine the relations between body mass index (BMI), dietary iron, and dietary factors affecting iron bioavailability, iron status, and inflammation [C-reactive protein (CRP)] in a transition country where obesity and ID are common. DESIGN Data from the 1999 Mexican Nutrition Survey, which included 1174 children (aged 5-12 y) and 621 nonpregnant women (aged 18-50 y), were analyzed. RESULTS The prevalence of obesity was 25.3% in women and 3.5% in children. The prevalence of ID was significantly (P < 0.05) higher in obese women and children compared with normal-weight subjects [odds ratios (95% CIs): 1.92 (1.23, 3.01) and 3.96 (1.34, 11.67) for women and children, respectively]. Despite similar dietary iron intakes in the 2 groups, serum iron concentrations were lower in obese women than in normal-weight women (62.6 ± 29.5 compared with 72.4 ± 34.6 μg/dL; P = 0.014), and total-iron-binding capacity was higher in obese children than in normal-weight children (399 ± 51 compared with 360 ± 48 μg/dL; P < 0.001). CRP concentrations in obese women and children were 4 times those of their normal-weight counterparts (P < 0.05). CRP but not iron intake was a strong negative predictor of iron status, independently of BMI (P < 0.05). CONCLUSIONS The risk of ID in obese Mexican women and children was 2-4 times that of normal-weight individuals at similar dietary iron intakes. This increased risk of ID may be due to the effects of obesity-related inflammation on dietary iron absorption. Thus, ID control efforts in Mexico may be hampered by increasing rates of adiposity in women and children.

Iodine deficiency in pregnancy, infancy and childhood and its consequences for brain development

Iodine deficiency during foetal development and early childhood is associated with cognitive impairment. Randomised clinical studies in school-aged children encountered in the literature indicate that cognitive performance can be improved by iodine supplementation, but most studies suffer from methodological constraints. Tests to assess cognitive performance in the domains that are potentially affected by iodine deficiency need to be refined. Maternal iodine supplementation in areas of mild-to-moderate iodine deficiency may improve cognitive performance of the offspring, but randomised controlled studies with long-term outcomes are lacking. Studies in infants or young children have not been conducted. The best indicators for iodine deficiency in children are thyroid-stimulating hormone (TSH) in newborns and thyroglobulin (Tg) in older children. Urinary iodine may also be useful but only at the population level. Adequate salt iodisation will cover the requirements of infants and children as well as pregnant women. However, close monitoring remains essential.

Oral iron supplements increase hepcidin and decrease iron absorption from daily or twice-daily doses in iron-depleted young women

Iron supplements acutely increase hepcidin, but the duration and magnitude of the increase, its dose dependence, and its effects on subsequent iron absorption have not been characterized in humans. Better understanding of these phenomena might improve oral iron dosing schedules. We investigated whether the acute iron-induced increase in hepcidin influences iron absorption of successive daily iron doses and twice-daily iron doses. We recruited 54 nonanemic young women with plasma ferritin ≤20 µg/L and conducted: (1) a dose-finding investigation with 40-, 60-, 80-, 160-, and 240-mg labeled Fe as [(57)Fe]-, [(58)Fe]-, or [(54)Fe]-FeSO4 given at 8:00 am fasting on 1 or on 2 consecutive days (study 1, n = 25; study 2, n = 16); and (2) a study giving three 60-mg Fe doses (twice-daily dosing) within 24 hours (study 3, n = 13). In studies 1 and 2, 24 hours after doses ≥60 mg, serum hepcidin was increased (P < .01) and fractional iron absorption was decreased by 35% to 45% (P < .01). With increasing dose, fractional absorption decreased (P < .001), whereas absolute absorption increased (P < .001). A sixfold increase in iron dose (40-240 mg) resulted in only a threefold increase in iron absorbed (6.7-18.1 mg). In study 3, total iron absorbed from 3 doses (2 mornings and an afternoon) was not significantly greater than that from 2 morning doses. Providing lower dosages (40-80 mg Fe) and avoiding twice-daily dosing maximize fractional absorption. The duration of the hepcidin response supports alternate day supplementation, but longer-term effects of these schedules require further investigation. These clinical trials were registered at www.ClinicalTrials.gov as #NCT01785407 and #NCT02050932.

Urinary Iodine Concentrations Indicate Iodine Deficiency in Pregnant Thai Women but Iodine Sufficiency in Their School-Aged Children

The median urinary iodine concentration (UI) in school-aged children is recommended for assessment of iodine nutrition in populations. If the median UI is adequate in school-aged children, it is usually assumed iodine intakes are also adequate in the remaining population, including pregnant women. But iodine requirements sharply increase during pregnancy. In this study, our aim was to measure UI in pairs of pregnant women and their school-aged children from the same family, who were sharing meals, to directly assess whether a household food basket that supplies adequate iodine to school-aged children also meets the needs of pregnant women. UI was measured in spot urine samples from pairs (n = 302) of healthy pregnant mothers and their school-aged children in metropolitan Bangkok, Thailand. A dietary questionnaire was completed. The UI [median (range)] in the pregnant women {108 (11-558) microg/L [0.85 (0.086-4.41) micromol/L]} were lower than those of their school-aged children {200 (25-835) microg/L [1.58 (0.20-6.52) micromol/L]} (P < 0.001), indicating optimal iodine status in the children but mild-to-moderate iodine deficiency in their pregnant mothers. The estimated iodine intakes in the 2 groups were in the range of 130-170 microg/d. There was a modest positive correlation between UI in the pairs (r = 0.253; P < 0.01). A higher frequency of seafood meals was a significant predictor of UI in both groups, but household use of iodized salt was not. These data suggest the median UI in school-aged children should not be used as a surrogate for monitoring iodine status in pregnancy in central Thailand; pregnant women should be directly monitored.

Anemia in relation to body mass index and waist circumference among Chinese women

BackgroundThis study aimed to investigate the relationship of anemia and body mass index among adult women in Jiangsu Province, China. Data were collected in a sub-national cross-sectional survey, and 1,537 women aged 20 years and above were included in the analyses. Subjects were classified by body mass index (BMI) categories as underweight, normal weight, overweight and obese according to the Chinese standard. Central obesity was defined as a waist circumference ≥ 80 cm. Anemia was defined as hemoglobin concentration < 12 g/dl. Prevalence ratios (PRs) of the relationship between anemia and BMI or waist circumference were calculated using Poisson regression.FindingsOverall, 31.1% of the Chinese women were anemic. The prevalence of overweight, obesity and central obesity was 34.2%, 5.8% and 36.2%, respectively. The obese group had the highest concentrations of hemoglobin compared with other BMI groups. After adjustment for confounders, overweight and obese women had a lower PR for anemia (PR: 0.72, 95% CI: 0.62-0.89; PR: 0.59, 95% CI: 0.43-0.79). Central obesity was inversely associated with anemia.ConclusionIn this Chinese population, women with overweight/obesity or central obesity were less likely to be anemic as compared to normal weight women. No measures are required currently to target anemia specifically for overweight and obese people in China.

Biofortified yellow cassava and vitamin A status of Kenyan children: a randomized controlled trial.

BACKGROUND Whereas conventional white cassava roots are devoid of provitamin A, biofortified yellow varieties are naturally rich in β-carotene, the primary provitamin A carotenoid. OBJECTIVE We assessed the effect of consuming yellow cassava on serum retinol concentration in Kenyan schoolchildren with marginal vitamin A status. DESIGN We randomly allocated 342 children aged 5-13 y to receive daily, 6 d/wk, for 18.5 wk 1) white cassava and placebo supplement (control group), 2) provitamin A-rich cassava (mean content: 1460 μg β-carotene/d) and placebo supplement (yellow cassava group), and 3) white cassava and β-carotene supplement (1053 μg/d; β-carotene supplement group). The primary outcome was serum retinol concentration; prespecified secondary outcomes were hemoglobin concentration and serum concentrations of β-carotene, retinol-binding protein, and prealbumin. Groups were compared by using ANCOVA, adjusting for inflammation, baseline serum concentrations of retinol and β-carotene, and stratified design. RESULTS The baseline prevalence of serum retinol concentration <0.7 μmol/L and inflammation was 27% and 24%, respectively. For children in the control, yellow cassava, and β-carotene supplement groups, the mean daily intake of cassava was 378, 371, and 378 g, respectively, and the total daily supply of provitamin A and vitamin A from diet and supplements was equivalent to 22, 220, and 175 μg retinol, respectively. Both yellow cassava and β-carotene supplementation increased serum retinol concentration by 0.04 μmol/L (95% CI: 0.00, 0.07 μmol/L); correspondingly, serum β-carotene concentration increased by 524% (448%, 608%) and 166% (134%, 202%). We found no effect on hemoglobin concentration or serum concentrations of retinol-binding protein and prealbumin. CONCLUSIONS In our study population, consumption of yellow cassava led to modest gains in serum retinol concentration and a large increase in β-carotene concentration. It can be an efficacious, new approach to improve vitamin A status. This study was registered with clinicaltrials.gov as NCT01614483.

Iodine supplementation in pregnancy and its effect on child cognition.

Maternal hypothyroidism and hypothyroxenemia due to iodine deficiency have been shown to affect development of the newborn negatively. Maternal iodine supplementation may therefore improve cognitive performance of the offspring, even in areas of mild-to-moderate iodine deficiency (ID). Several iodine supplementation studies have been performed in mildly ID pregnant women in Europe. These studies have shown that iodine supplementation increases maternal urinary iodine (UI) excretion and reduces thyroid volume, as well as prevents increases in infant thyroid volume and thyroglobuline. However, randomized controlled studies with long-term outcomes are lacking. Therefore, two trials were started in 2008 in areas of low iodine status; one in Bangalore, India (n=325), and another in Bangkok, Thailand (n=514). Pregnant women were recruited <14 weeks gestational age and randomized to either receive a daily dose of 200 μg I (as KI) or an identical placebo throughout pregnancy. Both trials are ongoing, and women are followed up during pregnancy and at delivery. UI, thyroid hormones, and thyroid size are measured. Birth outcomes are recorded, such as gestational age at delivery, height, weight, and APGAR scores, and cord blood and heel stick blood (<72 h) is collected from the child. Child development is assessed at 6 weeks of age using the Neonatal Behavioral Assessment Scale (NBAS), and at 12 and 24 months of age using the Bayley Scales of Infant Development. The outcomes of these trials will contribute importantly to the evidence base for iodine supplementation of pregnant women living in areas of mild iodine deficiency.

Biofortified Cassava with Pro-Vitamin A Is Sensory and Culturally Acceptable for Consumption by Primary School Children in Kenya

Background Biofortification of cassava with pro-vitamin A can potentially reduce vitamin A deficiency in low-income countries. However, little is known about consumer acceptance of this deep yellow variety of cassava compared to the commonly available white varieties. We aimed to determine the sensory and cultural acceptability of the consumption of pro-vitamin A rich cassava in order to identify key factors predicting the intention to consume pro-vitamin A rich cassava by families with school-aged children in Eastern Kenya. Methods Sensory acceptability was measured by replicated discrimination tests and paired preference tests among 30 children (7–12 yr) and 30 caretakers (18–45 yr) in three primary schools. Cultural acceptability was assessed with a questionnaire based on the combined model of The Theory of Planned Behavior and The Health Belief Model in one primary school among 140 caretakers of children aged 6 to 12 years. Correlations and multivariate analyses were used to determine associations between summed scores for model constructs. Results Caretakers and children perceived a significant difference in taste between white and pro-vitamin A rich cassava. Both preferred pro-vitamin A rich cassava over white cassava because of its soft texture, sweet taste and attractive color. Knowledge about pro-vitamin A rich cassava and its relation to health (‘Knowledge’ ((β = 0.29, P = <.01)) was a strong predictor of ‘Health behavior identity’. Worries related to bitter taste and color (‘Perceived barriers 1’ (β = −0.21, P = .02)), the belief of the caretaker about having control to prepare cassava (‘Control beliefs’ (β = 0.18, P = .02)) and activities like information sessions about pro-vitamin A rich cassava and recommendations from health workers (‘Cues to action’(β = 0.51, P = <.01)) were the best predictors of intention to consume pro-vitamin A rich cassava. Conclusions Pro-vitamin A rich cassava is well accepted by school children in our study population.

Quantifying folate bioavailability: a critical appraisal of methods

Purpose of reviewDietary reference intakes for folate rely on a good estimate of folate bioavailability from the general diet. In this review, current methods for quantifying the bioavailability of dietary folate and specific folate vitamers in humans are reviewed. Emphasis is on isotopic labeling techniques that have been developed during the past 15 years. Recent findingsMost reported studies applied single-dose designs, in which blood or urine concentrations of folate are measured for several hours after oral folate administration. To obtain a measurable biochemical response, however, relatively high doses of folic acid are administered and individuals are often saturated with large doses of folic acid prior to study. The effect of this on folate absorption and metabolism is poorly understood. Therefore, study designs in which multiple oral doses are administered are preferred. Several such studies, both with unlabeled and isotopically labeled folic acid, are discussed. Although many studies have been performed on the bioavailability of specific folate compounds and of folate from single foods, reliable data in which the bioavailability of folate from total diets have been measured are currently lacking. SummaryA multiple oral dose design is the best approach for measuring folate bioavailability because there are several serious drawbacks to designs based on the use of a single oral dose. Studies on folate bioavailability from total diets are urgently required in order to evaluate current recommendations for folate intake.

Validation of a food frequency questionnaire to assess folate intake of Dutch elderly people

Folate is required for 1-carbon metabolism and deficiency in folate leads to megaloblastic anemia. Low levels of folate have been associated with increased risk of vascular disease. To investigate whether RDA of folate are met, habitual folate intake needs to be assessed reliably. We developed a FFQ to specifically measure folate intake over the previous 3 months in elderly people in the Netherlands. Major sources of folate intake, i.e. foods contributing to at least 80% of the average folate intake, were identified through an analysis of the second Dutch Food Consumption Survey for the sub-population of men and women aged 50-70. In 2000 and 2001, folate intake was estimated with this questionnaire in 1286 individuals aged 50-75 years. Concentrations of serum and erythrocyte folate served as biomarkers with which relative validity of the questionnaire was assessed. The same FFQ was repeated after 3 years in 803 subjects in order to assess long-term reproducibility. Mean folate intake was estimated to be 196 (SD 69) microg/d. Spearman correlation coefficients between folate intake and serum and erythrocyte concentrations were 0.14 (P < 0.01) and 0.05 (P = 0.06) respectively. Spearman correlations between folate intakes measured at baseline and after 3 years were 0.58 (P < 0.01). 47% of the participants were classified in the same quartiles on the two occasions. Our FFQ showed a weak correlation between folate intake and blood folate concentrations and reproducibility was acceptable. This FFQ is able to rank subjects according to their folate intake.