Archive for May, 2017

Identification of a Hemolysis Threshold That Increases Plasma and Serum Zinc Concentration

Killilea DW, Rohner F, Ghosh S, Otoo GE, Smith L, Siekmann JH, King JC

May 2017 – Journal of Nutrition

Plasma or serum zinc concentration (PZC or SZC) is the primary measure of zinc status, but it is not established how much hemolysis can occur without changing PZC/SZC concentrations. To estimate the effect of hemolysis on PZC/SZC concentrations, this study calculated a hemolysis threshold and then compared it with results from an in vitro study and a population survey. This study found a 5% increase in PZC/SZC was calculated to result from the lysis of 1.15% of the erythrocytes in whole blood, corresponding to ~1 g hemoglobin/L added into the plasma or serum. Similarly, the addition of simulated hemolysate to control plasma in vitro caused a 5% increase in PZC when hemoglobin concentrations reached 1.1860.10 g/L. In addition, serum samples from a population nutritional survey were scored for hemolysis and analyzed for changes in SZC; samples with hemolysis in the range of 1–2.5 g hemoglobin/L showed an estimated increase in SZC of 6% compared with non-hemolyzed samples. Each approach indicated that a 5% increase in PZC/SZC occurs at ~1 g hemoglobin/L in plasma or serum. This concentration of hemoglobin can be readily identified directly by chemical hemoglobin assays or indirectly by direct spectrophotometry or matching to a color scale. A threshold of 1 g hemoglobin/L is recommended for PZC/SZC measurements to avoid increases in zinc caused by hemolysis. The use of this threshold may improve zinc assessment for monitoring zinc status and nutritional interventions.

Efficacy of iron-biofortified crops

Boy E, Haas JD, Petry N, Cercamondi CI, Gahutu JB, Mehta S, Finkelstein JL,Hurrell RF

April 2017 – African Journal of Food, Agriculture, Nutrition, and Development

Biofortification aims to increase the content of micronutrients in staple crops without sacrificing agronomic yield, making the new varieties attractive to farmers. Food staples that provide a major energy supply in low- and middle-income populations are the primary focus. The low genetic variability of iron in the germplasm of most cereal grains is a major obstacle on the path towards nutritional impact with these crops, which is solvable only by turning to transgenic approaches. However, biofortified varieties of common beans and pearl millet have been developed successfully and made available with iron contents as high as 100 mg/kg and 80 mg/kg, respectively, two to five times greater than the levels in the regular varieties. This brief review summarizes the research to date on the bioavailability and efficacy of iron-biofortified crops, highlights their potential and limitations, and discusses the way forward with multiple biofortified crop approaches suitable for diverse cultures and socio-economic milieu. Like post-harvest iron fortification, these biofortified combinations might provide enough iron to meet the additional iron needs of many iron deficient women and children that are not covered at present by their traditional diets.

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