Maize inbreds from different heterotic groups as favorable sources for increased potential bioavailability of magnesium, iron, manganese and zinc

Malnutrition, as a global problem, is mainly caused by low level of mineral elements in staple food (deficient soil). Biofortification is based on selection of genotypes with enhanced concentration of mineral elements in grain, as well as decreased concentration of substances which interfere bioavailability of mineral elements in gut (like phytic acid), and increased content of substances that increase availability (such as β-carotene). The experiment with 51 maize ( Zea mays L.) inbred lines with different heterotic background was set up in order to evaluate chemical composition of grain and to determine the relations between phytic acid (PA), β-carotene, and mineral elements: Mg, Fe, Mn, and Zn. The highest average phytate, β-carotene, Fe, and Mn content was found in grain of inbreds from Lancaster heterotic group. The highest content of Mg was in grain of Independent source and Zn in grain of BSSS group. Increased level of Fe and Mn in Lancaster lines could be partially affected by higher PA content in grain, while increased β-carotene content could improve Mn and Zn availability from grain of BSSS genotypes and Mg availability from Lancaster inbreds. It is important to underline that PA reduction is followed by Zn content increase in grain of Lancaster heterotic group, as well as that variations in Mg, Fe, and Mn contents are independent on PA status in inbreds from Independent source, indicating that the genotypes with higher Mg, Fe and Mn status from this group could serve as favorable source for improved Mg, Fe, and Mn absorption.

Factors Associated With Changes in Magnesium Levels in Asymptomatic Neonates: A Longitudinal Analysis

Background: Neonates and infants with hypomagnesemia present with seizures and psychomotor delay. Objectives: The present study evaluated the changes in magnesium (Mg) levels and factors associated with these in the first three days of life. Materials and Methods: We monitored 50 clinically asymptomatic neonates; they were not given any magnesium supplements even if they had hypomagnesemia at baseline. The variables analysed were: serum Mg; gestational age; birth weight; length; and the ponderal index. We used random effects (RE) models for longitudinal analysis of these data. Results: The mean standard deviation (SD) gestational age was 36.3 (3.6) weeks and the mean (SD) weight was 2604.2 (754.4) grams. About 31% of the neonates had hypomagnesemia (< 1.6 mg/dL) on day one; however, all had normal magnesium levels by day three of life (P < 0.001). At birth, after adjusting for intrauterine growth retardation status (IUGR), serum Mg levels were lower by 0.0097 mg/dL (95% CI: -0.019 to -0.0003) per 100 grams increase in weight of the neonate. After adjusting for IUGR status, the mean increase in the serum Mg levels was 0.14 mg/dL (95% confidence intervals [CI]: 0.10 to 0.18) per day. The per-day increase in magnesium levels was significantly higher in low birth weight babies (0.10, 95% CI: 0.01 to 0.18) compared with normal birth weight babies. Conclusions: Asymptomatic neonates may have a high prevalence of hypomagnesemia; however, the levels become normal without any magnesium supplementation. Even though regular monitoring of magnesium levels is useful, no supplements are required - particularly in clinically asymptomatic neonates.