In Overweight Women, Adiposity-related Inflammation and Serum Hepcidin are Increased, Dietary Iron Bioavailability is decreased and Ascorbic Acid has Only a Negligible Enhancing Effect on Iron Bioavailability.

Objectives: Many countries are struggling with the double burden of malnutrition. Iron deficiency is prevalent in overweight and obese (OW/OB) subjects, likely due to adiposity-related inflammation increased hepcidin and decreased iron absorption. Because hepcidin reduces iron efflux from the basolateral enterocyte, whether luminal enhancers of iron absorption, like ascorbic acid (AA), would be effective in OW/OB subjects is uncertain. We compared iron bioavailability (FeB) from non-inhibitory meals with and without AA in normal weight (NW), OW, and OB women. Methods: In a randomized crossover study in young women (NW=25, OW=20 and OB=19), FeB from a test meal without (A) and with (B) AA was measured by using erythrocyte incorporation of Fe isotopic labels at 14d. Results: Inflammation and serum hepcidin were lower in the NW versus OW and OB. FeB from meal A was 20% in NW versus 12% in OW and 12% in OB (NW vs OW/OB: P=0.049). FeB from meal B was 28% in NW versus 15% in OW and 16% in OB (NW vs OW/OB: P=0.004). The %increase in FeB comparing A to B was greater in the NW (P<0.001) than in OW (P=0.178) or OB (P=0.008). Higher hepcidin predicted lower FeB (A:β=-0.458, P<0.001) Conclusions: Serum hepcidin is higher and FeB is lower in OW/OB compared to NW subjects. Moreover, the enhancing effect of AA on FeB in OW/OB subjects is blunted, consistent with the hypothesis that increased hepcidin in OW/OB limits iron absorption. The widespread increase in obesity may limit current dietary strategies to improve FeB in anemic women.

Effect of Provitamin A-biofortified Cassava on Vitamin A Status of Kenyan Children: A Randomised Controlled Trial.

Objectives: To measure the effect of daily consumption of provitamin A-biofortified cassava on vitamin A status in children aged 5-13 years. Methods: Mild-to-moderate vitamin A deficient children (n=342) were randomly allocated to groups receiving: 1) 375 g of white cassava and placebo supplement; 2) 375 g of white cassava and a supplement of β-carotene (1,054 μg); 3) 375 g of biofortified cassava and placebo supplement. Children received the intervention 6 days/week for 18.5 weeks. Field staff and participants were blinded to supplementation. Cooked cassava was mashed with salt and 4 g of oil per portion. Biofortified cassava supplied 208 μg RAE, which is ~50% of the age-specific estimated average requirement for vitamin A for children. The primary endpoint was serum retinol concentration and secondary endpoint was serum β-carotene concentration, both at end of intervention; in the analysis, we adjusted for sex and serum concentrations at baseline of retinol, C-reactive protein and α1-acid-glycoprotein. Results: Complete data were collected for 337 children. Compliance to cassava feeding was similar between treatment groups. Preliminary results showed that consumption of biofortified cassava and β-carotene supplementation resulted in a similar increase in retinol concentrations (for both interventions, mean: 0.81 μmol/L versus 0.77 μmol/L; difference, 95% CI: 0.04 μmol/L, 0.00─0.07 μmol/L) but in a different increase in serum β-carotene concentration (for β-carotene supplement group, mean: 0.25 μmol/L (95% CI: 0.17─0.33), for biofortified cassava group, mean: 0.81 μmol/L (95% CI: 0.73-0.88)) Conclusions: Provitamin A-biofortified cassava improves the vitamin A status of primary school children in Kenya.

Gene-environment Interactions of Specific TF and HAMP Gene Variants in Relation to Iron Status in Black South Africans.

Objectives: Besides understanding the genetic determinants of iron status, investigations on how these interact with environmental factors to influence iron status are crucial. The objective of our study was to determine interaction between single nucleotide polymorphisms (SNPs) within the transferrin gene (TF-rs1799852) and hepcidin antimicrobial peptide gene (HAMP-rs10421768) and environmental factors within a population of black South Africans. Methods: Genotypes were determined in a subset of women of Tswana ancestry (n=686) who were part of the South African prospective urban and rural epidemiological (PURE) study, and were associated with concentrations of serum ferritin (SF), soluble transferrin receptor (STfR) and body iron (BI). C-reactive protein was included as a co-variate. Results: Iron intake was 11.0 g/d and 13.5 g/d in the rural and urban site respectively. Overall, rural subjects had lower SF and BI, and higher sTfR in comparison to their urban counterparts (P<0.05). Concentrations of SF, sTfR and BI were not different between rs10421768 genotypes. Concentrations of SF and BI in rural subjects harbouring the mutant allele (A) at rs1799852 were, 28.2μg/L and 26.3mg/kg. compared to 87.3μg/L, and 31.1mg/kg in homozygous wild type subjects (P<0.05). Urban subjects presented with no such differences. Conclusions: Residential area influenced the association of rs1799852 with serum concentration of ferritin, transferrin receptor and body iron, highlighting the importance to investigate geneenvironment interactions.

Maternal Thyroid Function and Birth Outcomes after Iodine Supplementation in Mild-to-moderately Iodine-deficient Pregnant Women in Thailand.

Objectives: To evaluate the effects of iodine supplementation in mild-to-moderately iodinedeficient pregnant Thai women on maternal thyroid function and birth outcomes. Methods: An RCT with 200 μg KI per day was conducted among 514 mild-to-moderately iodinedeficient pregnant Thai women. Blood samples were collected at baseline (<14 weeks of gestation), and follow up samples were collected in the 2nd, and 3rd trimester and at delivery in cord blood. Free T4 (fT4), thyroglobulin (TG) and thyroid-stimulating hormone (TSH) concentration were measured. Neonatal data was obtained from hospital records. Thyroid volume of the newborns was measured using ultrasonography. Data were analyzed per protocol by linear mixed models and linear regression models. Results: Cumulative loss to follow up was 20% in the 2nd trimester, 23% in the 3rd trimester, and 28% at delivery. Median maternal fT4, TG and TSH concentration did not differ significantly between treatment groups (p>0.05). Mean birth weight was 3150±410 g in the iodine group as compared to 3088±473 g in the placebo group (p>0.05); 4.8% of infants in the iodine group were low birth weight versus 7.9% in the placebo group. There were no significant differences in median fT4, TG and TSH concentration, and mean thyroid volume of the newborns between treatment groups (p>0.05). Conclusions: Maternal iodine supplementation normalized iodine status and resulted in lower maternal TSH concentrations during pregnancy. Further data analysis should reveal whether iodine supplementation has led to any improvement in child development in this population.

Proxy Markers of Serum Retinol Concentration, Used Alone and in Combination, to Assess Population Vitamin A Status in Kenyan Children.

Objectives: To assess the diagnostic performance of serum concentrations of retinol-binding protein (RBP), transthyretin, retinol concentration measured by fluorometry and RBP:transthyretin molar ratio, either alone or in combination, to estimate the prevalence of vitamin A deficiency (serum retinol concentration <0.70 μmol/L measured by high-performance liquid chromatography(HPLC)). Methods: A cross-sectional study was conducted in 15 primary schools in Kibwezi and Makindu districts in Eastern province, Kenya in June 2010 with 375 schoolchildren (6-12 years), 25 randomly selected from each school by lot quality assurance sampling. Results: Complete data were collected for 372 children. Mean serum concentration of retinol (HPLC), RBP and transthyretin were 0.87 (SD 0.19) µmol/L, 0.67 (SD 0.17) µmol/L and 3.0 (SD 0.62) µmol/L. The mean RBP: Transthyretin molar ratio was 0.23. The prevalence of vitamin A deficiency measured with HPLC was 18%. Transthyretin and RBP showed the largest area under the curve (AUCs 0.96 and 0.93, respectively). Logistic regression resulted in a model predicting vitamin A deficiency based on RBP, transthyretin and C-reactive protein (AUC: 0.98) and prevalence depending cutpoints for the linear predictor were calculated. Conclusions: Combination of transthyretin, RBP and C-reactive protein in a linear predictor showed excellent diagnostic performance in assessing vitamin A status, and has great potential to eventually replace serum retinol concentration measured by HPLC as the preferred method to assess the population burden of vitamin A deficiency. Further research is needed to confirm whether this linear predictor yields similar results in different populations and laboratories. Our methodology can be widely applied for other diagnostic aims.