Assessment of zinc Fortification of a Household- Based Water Filtration Device: Zn Absorption Using Stable Isotopes and Efficacy in a Controlled Trial in Beninese School Children.

Objectives: Zinc bioavailability from foods is limited due to the presence of absorption inhibitors. Water as a vehicle for zinc could be effective in improving zinc status. LifeStraw®Family (LSF) is a water filtration device that fortifies water with zinc. We assessed the absorption of zinc and the response of plasma zinc (PZn) to long-term consumption of the zinc fortified water. Methods: The LSF filters were placed in rural households in Benin (n=139) to assess compliance and acceptability. Bioavailability was measured in young adults with the urinary monitoring of two stable zinc isotopes. A double blind, randomised, controlled trial (RCT) was carried out in school children aged 5-10y (n=278) from a rural village in Benin. Over 20 weeks, including sparse midpoint sampling, children received either zinc fortified LSF-filtered water (Zn), non-fortified LSFfiltered water (Fltr) or non-fortified non-filtered water (Ctrl). The Zn group received a daily zinc dose of 4.6±2.2 mg. Results: Geometric mean (-SD,+SD) zinc absorption from fortified water was 65.9% (42.2,102.4). At baseline, mean PZn was 69.2±12.6 μg/dl and 35.9% of children were zinc deficient. During the RCT, there was a significant treatment effect on PZn (ANCOVA, p=0.029): final PZn in the Zn group was 4.2 and 1.9 μg/dl higher than the Fltr and the Ctrl group, respectively. Further analysis integrating the sparse midpoint PZn response will allow evaluation of plasma zinc kinetics. Conclusions: The LSF filter delivers water fortified with low doses of highly bioavailable zinc. Long-term consumption of zinc fortified water from the LSF filter improved zinc status in Beninese school children.

Evaluation of Zinc Bioavailability in Humans from Foliar Zinc Biofortified Wheat and from Intrinsic vs. Extrinsic Zn Labels in Biofortified Wheat.

Objectives: Zinc biofortification may be a sustainable way to improve Zn status, but questions remain on Zn bioavailability. We produced a novel biofortified wheat by Zn foliar application, and a separate wheat cultivar was intrinsically labeled with a Zn stable isotope. Goals were: a) To compare fractional and total Zn absorption (FAZ-TAZ) from chapattis prepared with biofortified, regular and postharvest fortified wheat; b) Compare the absorption of intrinsically and extrinsically Zn labels from biofortified wheat. Methods: Chapattis were prepared from flours with 100% and 80% extraction rates (ER). Meals were administered to 2 women's groups (N=44) in randomized order. Bioavailability was measured with double isotopic urinary technique with stable isotopes; four-day urines were collected and isotopic enrichment measured. Results: Foliar Zn application resulted in an increase of 45.6% of grain Zn. The control and biofortified wheat contained 25±0.12 ppm and 46±1.37 ppm Zn and 0.830±0.04 g/100 g and 0.807 ±0.03 g/100 g PA. The Zn:PA molar ratio for the unfortified, fortified and biofortified meals were 36, 63, 63 (100% ER) and 40, 67, 67 (80% ER). Mean total Zn in the intrinsically labeled wheat was 19.9±1.6 ppm. FAZ-TAZ data from the absorption studies are being analyzed. Conclusions: Foliar application increased Zn concentration without significantly changing PA concentration, and extraction rate is a determinant of the Zn:PA ratio. Assessment of FAZ-TAZ will provide: a) Data on the potential of foliar zinc biofortified wheat, and b) proof that the double isotope technique used to assess absorption of extrinsic Zn labels in biofortified wheat is valid.

Using Stable Iron Isotopic Techniques and Serum Hepcidin Profiles to Optimize Iron Supplementation for Correction of Iron Deficiency in Young Women.

Objectives: Determine the duration and magnitude of the serum hepcidin (sHep) rise induced by oral iron (Fe) supplements from single and consecutive-day Fe doses and measure bioavailability in healthy subjects. Methods: Twenty six subjects (serum ferritin, SF <20 μg/L) were randomized in four groups and sHep, iron status and inflammation markers were monitored for 96 h. On day 1, no supplements were administered (control day). On days 2 and 3, subjects received iron supplements containing 40, 80, 160 and 240 mg Fe as FeSO4 in either single dose (SFe) or as two consecutive day doses (CDFe) labeled with stable iron isotopes 54FeSO4, 57FeSO4, 58FeSO4. Iron bioavailability was measured by assessing the isotopic enrichment of erythrocytic iron 14 days after stable isotope administration. Results: There was a significant effect of time of day (P<0.05) and iron dose on sHep (P<0.05). Compared to control days, sHep was significantly higher at 8h and 24h after administration for 80, 160 and 240 mg doses (P<0.05) but not for 40 mg. Iron absorption from the second CDFe dose compared to SD was not significantly decreased for 40 mg, but was decreased 37% for 80 mg, 31% for 160 mg and 45% for 240 mg (for all, P<0.01). Fractional absorption was highest from the 40 mg dose. Conclusions: In Fe-depleted women, CDFe at 80 mg or above increase sHep and this decreases iron bioavailability, while a dose of 40 mg does not. These important new data will help design optimal dosing regimens for Fe supplements in women.

Effects of High and Low Dose Iron-Containing Micronutrient Powders for In-Home Fortification of Complementary Foods on the Gut Microbiome and Gut Inflammation in Kenyan Infants.

Objectives: Primary outcome was change in composition of gut microbiome, after 3 weeks and 4 months. Secondary outcomes were changes in faecal calprotectin, treated diarrhoea, anaemia, iron status and systemic inflammation. Methods: We performed two randomized controlled trials in 6-month-old Kenyan infants consuming home-fortified maize porridge daily for four months. 1) infants received an MNP containing 2.5 mg iron as NaFeEDTA (+2.5 mgFeMNP) or the identical MNP without iron (-2.5 mgFeMNP). 2) a different MNP containing 12.5 mg iron as ferrous fumarate (+12.5 mgFeMNP) or the identical MNP without iron (-12.5 mgFeMNP). Results: We enrolled 117 infants, and 101 infants completed the studies between March 2010 and September 2012. Baseline prevalence of anaemia and systemic inflammation were 67.3% and 29.7%, respectively. At baseline, 63% of the total microbial 16S rRNA could be assigned to Bifidobacteriaceae; using qPCR, Salmonella was detected in 22.8% of infants, B. cereus in 38.6%, S. aureus in 71.3%, C. difficile in 53.5%, and C. perfringens in 86.1%. Body iron stores increased in the +12.5 mgFeMNP (p=0.001), but not in the +2.5 mgFeMNP. Using pyrosequencing, +FeMNPs increased enterobacteria, especially Escherichia/Shigella (p=0.048), the enterobacteria/ bifidobacteria ratio (p=0.020), and Clostridium (p=0.03) compared to -FeMNPs; +FeMNPs also increased faecal calprotectin (p=0.002). Most of these effects were confirmed using qPCR, and many were statistically stronger in ±12.5 mgFeMNP study than in ±2.5 mgFeMNP study. During the trial, 27.3% of infants in the +12.5 mgFeMNP group required treatment for diarrhoea vs. 8.3% in the -12.5 mgFeMNP group (p=0.092). Conclusions: In rural Africa where infectious disease burden is high, provision of iron-containing MNPs to infants increases gut inflammation and modifies the gut microbiome toward a potentially more pathogenic profile.