Will rising household incomes solve China's micronutrient deficiency problems?

Rapid economic growth in China has resulted in substantially improved household incomes. Diets have also changed, with a movement away from traditional foods and towards animal products and processed foods. Yet micronutrient deficiencies, particularly for calcium and vitamin A, are still widespread in China. In this research we model the determinants of the intakes of these micronutrients using household panel data, asking particularly whether continuing income increases are likely to cause the deficiencies to be overcome. Nonparametric kernel regressions and random effects panel regression models are employed. The results show a statistically significant but relatively small positive income effect on both nutrient intakes. The local availability of milk is seen to have a strong positive effect on intakes of both micronutrients. Thus, rather than relying on increasing incomes to overcome deficiencies, supplementary government policies, such as school milk programmes, may be warranted.

Dinuclear copper and zinc complexes of a hexaazamacrocycle containing p-xylyl spacers and bridging anions: theoretical and spectroscopic studies

The hexaazamacrocycle 7,22-dimethyl-3,7,11,18,22,26-hexaazatricyclo[26.2.2.2(13,16)] tetratriaconta-1(30), 13,15,28,31,33- hexaene (Me-2[30] pbz(2)N(6)) was synthesized and characterised by single crystal X-ray diffraction. The macrocycle adopts a conformation with the two aromatic rings almost parallel at a distance of ca. 4.24 Angstrom, but displaced relative to each other by ca. 1.51 Angstrom. The protonation constants of this compound and the stability constants of its complexes with Cu2+ and Zn2+, were determined in water - methanol (9 : 1 v/v) at 25 degreesC with ionic strength 0.10 mol dm(-3) in KCl. The potentiometric and spectroscopic studies (NMR of zinc, cadmium and lead complexes, and EPR of the copper complexes) indicate the formation of only dinuclear complexes. The association constants of the dinuclear copper complex with anions ( thiocyanate, terephthalate and glyphosate) and neutral molecules (1,4-benzenedimethanol, p-xylylenediamine and terephthalic acid) were determined at 20 degreesC in methanol. The structural preferences of this ligand and of its dinuclear copper(II) complex with a variety of bridging ligands were evaluated theoretically by molecular mechanics calculations (MM) and molecular dynamics (MD) using quenching techniques.

Zinc(II)-pyridylthioazophenol system: synthesis, characterization and crystal structure

Reactivities of pyridylthioazophenols (1) with zinc(II) salts have been studied and the complexes isolated in pure form and characterized. Pyridylthioazophenols react with zinc( II)acetate in MeOH/EtOH at room temperature to give a series of pyridylsulfinylazophenols (2)but no zinc( II) complex. The sulfoxides (2) have been characterized by IR and NMR. One of the pyridylsulfinylazophenols (2a) has been subjected to single-crystal X-ray analysis in order to confirm details of its structure. A series of dimeric zinc( II) complexes of tetradentate NSNO pyridylthioazophenolates has been isolated through reaction of zinc nitrate in MeOH followed by in situ reaction with azide ion, which acts as a mu-(1,1) bridge. All complexes have been characterized spectroscopically. The detailed structure of one of the dinuclear zinc( II) complexes has been established by a single-crystal X-ray structure determination. In complex 3a two octahedrally coordinated zinc( II) ions are bridged by two end-on azide ions. No reactions of pyridylthioazophenols with zinc chloride in refluxing EtOH have been observed.

A monoaqua zinc complex. Unique acid dissociation behaviour

Using the I : 2 condensate of benzil dihydrazone and 2-acetylpyridine as the ligand L, two complexes of zinc, [ZnL(CH3COO)]PF6 (1) and [ZnL(H2O)CIO4]CIO4 H2O (2), are synthesised from Zn(CH3COO)(2).2H(2)O and Zn(CIO4)(2).6H(2)O, respectively. From X-ray crystallography, both the complexes are found to be single helical with the metal in distorted octahedral N4O2 environment. In 1, the two oxygen atoms come from the bidentate acetate while 2 is a monoaqua complex with a perchlorate anion bound to the metal in monodentate fashion. The perchlorate in 2 is not at all weakly bound [Zn-O(perchlorate) 2.256(4) A]. Still in acetonitrile solution, the coordinated perchlorate ion dissociates upon deprotonation [reaction (i)].

Zinc(II) mediated synthesis of an N-substituted 2-(2-pyridyl)imidazole from a 1,2-diketone and 2-(aminomethyl)pyridine and its ligational behaviour

Reaction of anhydrous ZnCl2 with the 1:2 condensate (L) of benzil and 2-(aminomethyl)pyridine in methanol gives monomeric ZnL'Cl-2 (1) where L' is 2-[(4,5-diphenyl-2-pyridin-2-yl-1H-imidazol-1-yl)-methyl]pyridine. In the X-ray crystal structure, 1 is found to contain tetrahedral zinc with an N2Cl2 coordination sphere and the N-substituent methylpyridine fragment hanging as a free arm. A tentative mechanism is proposed for the zinc mediated conversion of L-->L'. Demetallation of 1 by the action of aqueous NaOH yields L' in the free state. When L' is reacted with Zn(ClO4)(2).6H(2)O in a 1:2 molar proportion, [Zn(L')(2)](n)(ClO4)(2n).(H2O)(n/2).(CH2Cl2)(n/2) (2) is obtained. The zinc atom in 2, as revealed by X-ray crystallography, has a trigonal bipyramidal N-5 coordination sphere. There are two independent ligands in the asymmetric unit of 2. One of them bonds only to one zinc atom in a bidentate mode with the N-substituent methylpyridine hanging free while the other ligand binds to two different zinc atoms in a tridentate fashion, employing the N-substituent methylpyridine nitrogen atom to form the polymeric one-dimensional chain cation.

Synthesis and crystal structure of a 3-D zinc phosphate, [C5N2H14][Zn-2(PO3(OH))(3)], containing (4.8) net sheets

A new 3-D zinc phosphate, [C5N2H14][Zn-2(PO3(OH))(3)], has been synthesised under solvothermal conditions in the presence of 1-methylpiperazine. The structure, determined by single-crystal X-ray diffraction at 293 K (RMM = 520.9, orthorhombic, space group P2(1)2(1)2(1); a = 10.0517(2) &ANGS;, b = 10.4293(2) &ANGS; and c = 14.9050(5) &ANGS;; V = 1562.52 &ANGS;(3); Z = 4; R(F) = 2.60%, wR(F) = 2.93%), consists of vertex linked ZnO4 and PO3(OH) tetrahedra assembled into (4.8) net sheets which in turn are linked through further PO3(OH) units to generate a 3-D framework. 1-Methylpiperazinium cations reside within the 3-D channel system, held in place by a strong network of hydrogen bonds. The (4.8) net sheets occur in a number of zeolite structures e.g. ABW and GIS and related zinc phosphate phases. © 2004 Academie des sciences. Published by Elsevier SAS. All rights reserved.

Ditopic redox-active polyferrocenyl zinc(II) dithiocarbamate macrocyclic receptors: synthesis, coordination and electrochemical recognition properties

The synthesis of a range of ditopic polyferrocenyl zinc(II) dithiocarbamate macrocyclic receptors containing ferrocene groups on the macrocycle's periphery and/or as part of the cyclic cavity is reported. The assemblies have been characterised by a range of spectroscopic techniques, electrochemical studies and in two cases by X-ray structure determination. The ability of these host systems to bind and sense electrochemically anionic guest species, isonicotinate and benzoate, and neutral 4-picoline guest was examined by H-1 NMR and cyclic voltammetric titration studies. The strongest association was found between the isonicotinate anion and a dinuclear zinc(II) receptor whose macrocyclic cavity is of complementary size to complex this bidentate guest species in a cooperative manner. Cyclic voltammetric studies demonstrated that all receptors can electrochemically sense the binding of isonicotinate and benzoate via significant cathodic perturbations of the respective ferrocene redox couple.

Effect of dietary phytate and microbial phytase on mineral and trace element bioavailability- a literature review

Phytic acid (PA) is the main phosphorus storage compound in cereals, legumes and oil seeds. In human populations where phytate-rich cereals such as wheat, maize and rice are a staple food, phytate may lead to mineral and trace element deficiency. Zinc appears to be the trace element whose bioavailability is most influenced by PA. Furthermore, several studies in humans as well as in monogastric animals clearly indicate an inhibition of non-haem iron absorption at marginal iron supply due to phytic acid. In fact PA seems to be, at least partly, responsible for the low absorption efficiency and high incidence of iron deficiency anaemia evident in most developing countries, where largely vegetarian diets are consumed Microbial phytases have provided a realistic means of improving mineral availability from traditionally high-phytate diets. In fact it has been consistently shown that Aspergillus phytases significantly enhance the absorption of calcium, magnesium and zinc in pigs and rats. Furthermore there are a few studies in humans indicating an improvement of iron bioavailability due to microbial phytase.

Synthesis and crystal structure of a 3-D zinc phosphate, [C5N2H14][Zn2(PO3(OH))3], containing (4.8) net sheets

A new 3-D zinc phosphate, [C5N2H14][Zn-2(PO3(OH))(3)], has been synthesised under solvothermal conditions in the presence of 1-methylpiperazine. The structure, determined by single-crystal X-ray diffraction at 293 K (RMM = 520.9, orthorhombic, space group P2(1)2(1)2(1); a = 10.0517(2) &ANGS;, b = 10.4293(2) &ANGS; and c = 14.9050(5) &ANGS;; V = 1562.52 &ANGS;(3); Z = 4; R(F) = 2.60%, wR(F) = 2.93%), consists of vertex linked ZnO4 and PO3(OH) tetrahedra assembled into (4.8) net sheets which in turn are linked through further PO3(OH) units to generate a 3-D framework. 1-Methylpiperazinium cations reside within the 3-D channel system, held in place by a strong network of hydrogen bonds. The (4.8) net sheets occur in a number of zeolite structures e.g. ABW and GIS and related zinc phosphate phases. © 2004 Academie des sciences. Published by Elsevier SAS. All rights reserved.

Coordination behavior of symmetrical hexadentate O2N2S2-donor Schiff bases toward zinc (II): synthesis, characterization, and crystal structure

Two series of zinc(II) complexes of two Schiff bases (H2L1 and H2L2) formulated as [Zn(HL1/HL2)]ClO4 (1a and 1b) and [Zn(L1/L2)] (2a and 2b), where H2L1 = 1,8-bis(salicylideneamino)-3,6-dithiaoctane and H2L2 = 1,9-bis(salicylideneamino)-3,7-dithianonane, have been prepared and isolated in pure form by changing the chemical environment. Elemental, spectral, and other physicochemical results characterize the complexes. A single crystal X-ray diffraction study confirms the structure of [Zn(HL1)]ClO4 (1a). In 1a, zinc(II) has a distorted octahedral environment with a ZnO2N2S2 chromophore.

Iron and zinc status in multiple sclerosis patients with pressure sores

Measurements of weighted dietary intakes and plasma determinations of albumin, iron, zinc, ascorbic acid and TIBC were carried out on twenty female multiple sclerosis patients in a long-stay hospital for disabled people. The group included ten patients with a recent history of pressure sores, closely matched with ten patients without pressure sores. Mean daily intake of carbohydrate was found to be higher in the non-pressure sore group whilst intake of zinc was lower in this group. Intakes of all other nutrients were comparable between the two groups. For both groups, intakes of energy, folate, vitamin D, iron and zinc were less than recommended values. Mean plasma levels of albumin and iron were towards the lower limit of the normal range, whilst that for zinc was considerably less than the normal range. Plasma TIBC was slightly above the normal range. Levels of plasma iron and zinc were significantly lower in the pressure sore group. The data indicate that severely disabled hospitalized patients with multiple sclerosis may be at risk of poor nutritional status. The results suggest that in the presence of pressure sores, there are increased requirements for specific nutrients, notably zinc and iron. Consideration is given to the possible value of supplementation of these individuals.

Zinc metabolism in pregnant and lactating rats and the effect of varying iron: Zn in the diet

Pregnant rats were given control (46 mg iron/kg, 61 mg zinc/kg), low-Zn (6.9 mg Zn/kg) or low-Zn plus Fe (168 mg Fe/kg) diets from day 1 of pregnancy. The animals were allowed to give birth and parturition times recorded. Exactly 24 h after the end of parturition the pups were killed and analysed for water, fat, protein, Fe and Zn contents and the mothers' haemoglobin (Hb) and packed cell volume (PCV) were measured. There were no differences in weight gain or food intakes throughout pregnancy. Parturition times were similar (mean time 123 (SE 15) min) and there were no differences in the number of pups born. Protein, water and fat contents of the pups were similar but the low-Zn Fe-supplemented group had higher pup Fe than the low-Zn unsupplemented group, and the control group had higher pup Zn than both the low-Zn groups. The low-Zn groups had a greater incidence of haemorrhaged or deformed pups, or both, than the controls. Pregnant rats were given diets of adequate Zn level (40 mg/kg) but with varying Fe:Zn (0.8, 1.7, 2.9, 3.7). Zn retention from the diet was measured using 65Zn as an extrinsic label on days 3, 10 and 17 of pregnancy with a whole-body gamma-counter. A group of non-pregnant rats was also included as controls. The 65Zn content of mothers and pups was measured 24-48 h after birth and at 14, 21 and 24 d of age. In all groups Zn retention was highest from the first meal, fell in the second meal and then rose in the third meal of the pregnant but not the non-pregnant rats. There were no differences between the groups given diets of varying Fe:Zn level. Approximately 25% of the 65Zn was transferred from the mothers to the pups by the time they were 48 h old, and a further 17% during the first 14 d of lactation. The pup 65Zn content did not significantly increase after the first 20 d of lactation but the maternal 65Zn level continued to fall gradually.