Zinc and small babies

Plasma and erythrocyte zinc and birth weight in pre-eclamptic pregnancies

Plasma and erythrocyte zinc concentrations in 45 proteinuric pre-eclamptic Chinese women were measured. There was no difference in either the plasma or erythrocyte zinc concentration between pre-eclamptic patients with and without intrauterine growth retardation. There was no correlation between either plasma or erythrocyte zinc concentration with the gestation at delivery, birth weight, mean arterial pressure and plasma albumin concentration. On the other hand, both plasma albumin concentration and mean arterial pressure were significantly correlated to birth weight, and the mean arterial pressure was also significantly higher in patients with intrauterine growth retardation. Plasma and erythrocyte zinc are not useful as indices of severity in pre-eclampsia.

Plasma zinc and copper in pregnant Nigerian women at term and their newborn babies

The concentration of copper and zinc was determined by atomic absorption spectrophotometry in 26 normal Nigerian women at term and their newborn babies. Cord zinc was significantly greater than maternal zinc. In contrast, cord copper was lower than maternal copper. There was only a weak correlation between cord copper and maternal copper but none between cord zinc and maternal zinc. There was no correlation between maternal and cord zinc and neonatal birthweight. However, an inverse correlation was found between maternal and cord copper and neonatal birthweight. These results indicate that: (1) zinc has no effect on fetal growth in Nigerian women but (2) copper may have a negative effect on fetal growth.

Plasma zinc concentration and catch up growth in preterm infants

Changes in plasma zinc concentration during the period of catch up growth were examined in 44 preterm infants. Blood samples were collected at birth, 6, 12 and 24 weeks. Plasma zinc concentration showed a mean of 13.6 mumol/l at birth and dropped to 9.8 mumol/l at 6 weeks and rose to 11.3 and 15.4 mumol/l at 12 and 24 weeks respectively. Plasma zinc concentrations showed significant correlation with weight velocity at 12 weeks. Male infants had significantly lower plasma zinc concentrations than females at 12 weeks. Infants of gestational age more than 32 weeks had lower plasma zinc concentrations at 12 and 24 weeks than those of earlier gestations. At the same time males were growing faster than females and also infants of gestational ages more than 32 weeks were growing faster than those born at earlier gestations. These observations, together with the finding that the decline in zinc occurred during the phase of rapid growth, suggest that growth is the predominant modulator of plasma zinc concentration.

Muscle cell potassium, RNA and hydration in pregnancy and pre-eclampsia

Thirty four pregnant women from 26 to 38 weeks gestation and 24 pregnant women with pre-eclampsia gave samples of muscle (rectus abdominis) at caesarean section. Muscle samples were analysed for H2O, K+, Mg2+ and Na+. Cell extracellular H2O was partitioned by the use of the Cl- space. Also protein, nucleic acids and Zn2+ were determined. From 26 to 38 weeks gestation the concentration of K+ per litre of cell water ([Ki]) slowly declined. The slope was significant. Points for patients with pre-eclampsia fell below the line and analysis of covariance showed that the two populations were different (P less than 0.001). Patients A-J were regarded clinically as severe pre-eclamptics. Points for these patients, in general, fell between 1 and 2 SDs below the normal line. Since other cations per litre of muscle cell water did not change, questions are raised. is the cation gap filled by amino acids or does vascular spasm cause a leakage of K+ from muscle cells? Does hypotonicity eventually develop leading to water intoxication? The low oncotic pressure in pre-eclampsia (shown here), the negative free water clearance could all favour increased cell hydration (some evidence for this is presented here towards term). Assessment of available information concerning creatinine excretion during normal pregnancy and K40, K42 studies together with our own rodent studies leads us to believe that a significant increase in muscle mass occurs, but such may not be the case in pre-eclampsia since the reduction in RNA and Zn2+ concentrations in muscle would suggest excessive protein degradation.(ABSTRACT TRUNCATED AT 250 WORDS)

Zinc and copper concentration in plasma of pregnant women in Nigeria

The concentration of plasma zinc and copper were determined by atomic absorption spectrophotometry in 58 Nigerian women at various times in pregnancy and compared with those of 11 non-pregnant controls. The results showed 67.5% decrease in zinc and 100% increase in copper over non-pregnant levels at the end of pregnancy. The mean plasma zinc levels were appreciably lower and copper the same as published values for Caucasian women at similar periods in pregnancy. Furthermore, there was no correlation between plasma zinc and copper and neonatal birthweight. We conclude that (1) a significant proportion of pregnant women in Nigeria have biochemical hypozincemia; (2) this hypozincemia is not responsible for fetal growth retardation in this population and (3) there is at present no justification for giving routine zinc supplementation to pregnant women in Nigeria.

Plasma and erythrocyte zinc concentrations in pre-eclampsia

Plasma and erythrocyte zinc concentrations were measured in 28 Chinese pre-eclamptic women and 28 controls matched for parity, race and gestation. There were no differences in either the plasma or erythrocyte zinc concentrations between pre-eclamptic and control groups, although the mean birth weight (p less than 0.001) and period of gestation (p less than 0.001) at delivery in the control group were significantly higher. In the pre-eclamptic patients, those delivering before 37 weeks or those who gave birth to low birth weight (less than 2500 g), babies had a significantly higher plasma urate concentration (p less than 0.02) compared to the pre-eclamptic patients with better fetal outcome. However, the plasma and erythrocyte zinc concentrations between these subgroups were not significantly different. Our results suggest that zinc deficiency is unlikely to play a significant role in pre-eclampsia in our patients, and that measurement of plasma and erythrocyte zinc concentrations is of doubtful clinical value in the management of pre-eclampsia.

Maternal zinc and selenium status in pregnancies with a neural tube defect or elevated plasma alpha-fetoprotein

Zinc and selenium status was assessed in 30 non-pregnant women, 69 women during normal pregnancy, six with a fetus with a neural tube defect (NTD) and 16 who had a raised plasma alpha-fetoprotein (AFP) but no detectable fetal abnormality. Plasma zinc and selenium concentrations were significantly reduced in the second trimester of normal pregnancy compared with non-pregnant levels. A significant decrease in concentrations of zinc in plasma and selenium in plasma and leucocytes was observed in women in the third trimester compared with women in the second trimester. Women with a fetal NTD and women with an unexplained elevation of plasma AFP had significantly lower leucocyte concentrations of zinc and of selenium. Mean values for plasma zinc, plasma and erythrocyte selenium, and for the activity of glutathione peroxidase in whole blood did not differ from those for normal pregnancy.

Serum selenium and zinc concentrations in morbid obesity. Comparison of controls and patients with jejunoileal bypass

The concentrations of serum selenium and zinc (both in micromoles per litre) were determined in 18 patients 5-12 years after jejunoileal bypass and in 13 controls with untreated morbid obesity. Selenium concentrations were significantly lower in the operated patients than among controls, whereas there was no significant difference with regard to zinc. Ninety-five per cent confidence limits for the median difference between pre- and post-operative concentrations were 0.03-0.41 with regard to selenium and -0.3 to 2.7 with regard to zinc. Even though little is known about the clinical consequences of chronic selenium deficiency, substitution might prove beneficial.

Zinc concentrations in leucocytes of patients receiving antiepileptic drugs

To determine whether some of the side effects of antiepileptic drugs could be due to zinc depletion within tissues, zinc concentrations in the polymorphonuclear leucocytes in 26 epileptic patients receiving valproate or carbamazepine and 14 controls were assessed. There was no difference in zinc concentration in leucocytes among the three groups and no evidence of zinc depletion. Valproate and carbamazepine may affect the intracellular distribution of zinc.

Zinc in human health and disease

The importance of zinc in human health and disease has been reviewed by reporting data from the recent literature. The role of zinc in human nutrition, general health, skin diseases, acrodermatitis enteropathica, reproductive physiology and pathophysiology, pregnancy, non-insulin-dependent diabetes mellitus as well as atherosclerosis is discussed. The consequences of zinc deficiency and toxicity are also illustrated.

Zinc and genital infections

The zinc status of 19 patients with chronic or recurrent genital infections and 18 patients with non-recurrent genital infections was assessed by measuring plasma and leucocyte zinc concentrations. Neither group of patients had plasma or leucocyte zinc concentrations that differed significantly from those of matched healthy controls. Each of six patients with chronic candidiasis had anergy to candidal antigen, as shown by delayed cutaneous hypersensitivity to intradermal injection of the antigen, but their zinc status was normal. This study provided no evidence of zinc deficiency in this small number of patients with acute non-recurrent or chronic recurrent genital infections.

Nutrition and the unborn baby

Nutrition and consequently the development of the unborn baby is profoundly influenced by the maternal nutritional state from conception to birth. This paper reviews the nutritional aspects of pregnancy in the light of current knowledge, with special reference to the effects of various nutrients and vitamins. Perinatal mortality in relation to maternal diet and the teratogenic effects induced by the abuse of antiepileptic drugs and other agents are also discussed.

Maternal leucocyte zinc deficiency at start of third trimester as a predictor of fetal growth retardation

Leucocyte zinc concentrations were measured in 70 mothers at the beginning of the third trimester of pregnancy and compared with the weight centiles of their subsequently delivered babies. The median maternal leucocyte zinc concentrations rose progressively with weight centile. Thus the median leucocyte zinc concentration of the mothers delivering babies weighing below the 10th centile was 112 nmol/10(9) leucocytes and that of the mothers with babies weighing above the 90th centile was 229.5 nmol/10(9) leucocytes. A maternal leucocyte zinc concentration less than 120 nmol/10(9) leucocytes strongly predicted a baby weighing below the 10th centile (positive predictive value = 71.9%, negative predictive value = 91.5%, sensitivity = 64.3%, specificity = 81.8%). These findings suggest that maternal zinc concentration might have a role in antenatal screening, but larger studies are required.

Dietary fibre and mineral metabolism

Current dietary recommendations urge, inter alia, an increased consumption of fibre-containing foods. Some experimental studies made on various animals and man indicate that the associated increases in intakes of fibre and phytic acid may prejudice mineral status respecting calcium, magnesium, iron and zinc. An examination has been made of the experimental evidence, also of the epidemiological evidence on numerous types of populations, past and present, developing and developed. It has been concluded that diets high in fibre, characteristically do not have meaningful ill effects on well-being or unequivocally enhance morbidity. In particular populations in certain regions where deleterious effects have been reported it is judged that local factors, not wholly understood, are in operation. In assessing the extent of the benefit to be derived from the dietary changes urged, results must be viewed holistically and not in isolation. It is believed that the beneficial effects respecting reduced pronenesses to various degenerative diseases are likely to far outweigh the possible adverse effects of reduced bioavailability of mineral nutrients.

Zinc concentration in umbilical cord tissue and cord plasma in appropriate-for-gestational-age babies

Zinc concentration in cord plasma was determined in 148 healthy appropriate-for-gestational-age babies delivered at various gestational ages. Zinc concentration in cord tissue was also determined in 62 of these babies. There was a significant rise in the cord tissue zinc concentration just after the 35th week of gestational age; thereafter the levels remained relatively unchanged. The cord plasma zinc concentration decreased slightly with increasing gestational age, but these changes were not significant. There was a statistically significant positive correlation between cord tissue zinc concentration and birth weight. No correlation was found between cord plasma zinc concentration and birth weight or cord tissue zinc concentration.

Dietary copper intake in artificially fed infants

Plasma concentrations of copper and zinc and leucocyte concentrations of zinc were measured in mothers during later pregnancy, at delivery, and 8-10 weeks after birth, and plasma concentrations of copper and zinc were measured in their infants at delivery and 8-10 weeks after birth. The 145 infants were either breast fed or fed one of two milk formulas supplying copper at different concentrations. None of the infants achieved the minimum copper intakes recommended by the World Health Organisation (WHO). At 2 months of age there were no major differences in growth or health detected in infants fed the different copper intakes. Infant birth weight correlated well with the ratio of maternal venous plasma zinc:maternal leucocyte zinc at delivery. Maternal venous plasma copper and zinc concentrations at birth correlated with umbilical venous plasma copper and zinc concentrations. Infants fed the higher copper content formulas had a low mean plasma zinc concentration without a significant increase in the mean plasma copper concentration. The present WHO recommendations regarding minimum copper intakes for infants fed formulas cannot be achieved with currently available formulas and are probably wrong.

Feeding children: in the beginning--nutrition and pregnancy

The health and well-being of every child is affected by both the quality and quantity of food, but when does nutrition first begin to be important? Is it after the birth or from the moment of conception, or perhaps even before this? This paper will focus on the nutritional status of the mother, before as well as during pregnancy, and its relationship to the birth weight and subsequent health of the child. Pre-pregnant weight is a major factor affecting birth weight; underweight women may be at increased risk of delivering a low birthweight infant and of complications of pregnancy, whilst those who are excessively obese are at greater risk of gestational diabetes and hypertension. Animal studies have demonstrated that severe vitamin and mineral deficiencies have dramatic effects on reproductive outcome, and there is now growing evidence that even marginal deficiencies in women may have deleterious effects on pregnancy outcome. Nutrition interventions which involve low-risk women appear to have little effect but beneficial effects have been demonstrated in interventions directed at high-risk women. Information about nutrition should be the mainstay of any advice given to prospective parents.

Is aging inevitable? The intracellular zinc deficiency hypothesis of aging

A review of the literature suggests that an intracellular zinc deficiency may be the primary cause of the aging process. Zinc-metalloenzymes play an important role in many aspects of cellular metabolism including DNA replication, repair and transcription. The main enzymes affected by zinc deficiency may be specific for each cell type. Depending on which zinc enzymes are "overvulnerable", zinc deficiency may result in accumulation of useless (or toxic) materials, malproduction of essential proteins, a neoplastic change or cell death, thus explaining the variability in aging patterns in different cell types. There is no simple and reliable index of zinc status in humans and a therapeutic trial may be needed to establish zinc deficiency. Finding a zinc-compound which can enter the cell and avoid the development of intracellular zinc deficiency may retard the aging process and postpone age-related diseases.

Muscle cell growth and the distribution of water and electrolyte in human pregnancy

Ten normal pregnant women had muscle composition analyses (rectus abdominis) carried out at 39-40 weeks of pregnancy. Water, chloride (Cl), chloride space (ECV), non-chloride space (ICW), potassium (K), sodium (Na), magnesium (Mg) and zinc (Zn) determinations were carried out. Analyses for DNA (cell number), protein: DNA ratio (cell size), RNA and collagen were also performed. Similar analyses were performed on uterine muscle and placentae before and after perfusion with Earle's solution. Data from pregnant patients were compared with similar estimations carried out on rectus abdominis samples from 13 non-pregnant subjects undergoing gynaecological procedures. Muscle tissue and predicted muscle mass (MM) (which constitutes 40% of body weight) demonstrated that the gain in body K was due to the products of conception, that ICW decreased per unit weight in muscle (8%), ECV increased (41%) without a radical change in muscle water content (2%). Overall a 6 l gain in ECV and a 2 l gain in ICW can be accounted for during pregnancy. The results of this study indicate that added hydration excluding the products of conception (placenta, infant, uterus) is mainly extracellular. Intracellular Na concentration decreases (50%) and it is speculated that the cation gap is made up by H+ in the presence of extracellular alkalosis. Muscle cells diminish in size but cell number per gram is constant. Zinc content (Zn/DNA) decreases. Previous experimental work suggests that MM increases by about 10% during pregnancy and this information has been included in considerations but it remains to be shown to what extent total muscle cell numbers increase and as to whether such increased muscle growth remains following pregnancy.

Zinc and copper in Asian pregnancies--is there evidence for a nutritional deficiency?

In 92 Hindu Asians, 59% of them vegetarian, and 51 Europeans longitudinal measurements were made during pregnancy of the zinc and copper concentrations in plasma and hair together with urinary zinc excretion, as indices of their zinc and copper status. Maternal diets were assessed once at booking. Zinc intakes ranged from 3.1 to 16.9 mg/day, with average intakes least in vegetarian Hindus and most in Europeans. Average copper intakes ranged between 1.48 and 1.80 mg/day and were similar in the three patient groups. Both ethnic groups showed the pregnancy-associated fall in the plasma concentration of zinc and rise in that of copper but throughout the study Hindus had statistically significant lower levels of zinc and higher levels of copper than Europeans. Urinary zinc excretion was not only significantly lower throughout the study in Hindus than in Europeans but the increase in excretion which occurred after 20 weeks gestation was smaller. There were no ethnic differences in the zinc content of hair. Urinary zinc excretion correlated with both plasma zinc levels and dietary zinc. Mean birthweight in the Hindus was 2912 g and 34% of infants were below the 10th centile, using the Aberdeen standards, compared with 6% of the European babies (mean birthweight 3349 g). No association was found between crude or adjusted birthweight and any of the measures of zinc or copper status in either ethnic group. The Hindus had an apparently lower average zinc status than the Europeans, but there was no evidence that this had acted as a nutritional constraint and was the cause of their slower rate of intrauterine growth.

Zinc deficiency is not a cause for abortion, congenital abnormality and small-for-gestational age infant in Chinese women

Zinc concentration in serum and hair was measured in a cross-sectional study of 437 Chinese women of whom 310 were normal controls studied at various stages of pregnancy and up to 12 months after delivery. The rest had spontaneous abortions, fetuses with a birthweight below the 10th centile for gestation or congenital abnormalities. Zinc concentration fell throughout normal pregnancy, the fall being greater in serum than in hair. There was no correlation between serum and hair levels. The infant birthweight had a positive correlation with serum level but a negative correlation with hair level. Abortion, low birthweight and congenital abnormality were not associated with low concentrations of zinc in plasma or hair.

The effects of oral iron supplementation on zinc and magnesium levels during pregnancy

Serial changes in serum zinc and magnesium concentrations have been studied before conception, throughout pregnancy and at 12 weeks postpartum in 15 normal healthy women not receiving iron supplementation, 10 women receiving iron supplementation but otherwise having healthy pregnancies and five insulin-dependent diabetics who also received oral iron. Relative to pre-pregnancy values zinc concentrations progressively decreased throughout pregnancy reaching a nadir at 36 weeks gestation followed by an increase; pre-pregnancy values were achieved by 12 weeks postpartum. Magnesium concentrations also decreased throughout pregnancy reaching a nadir at 32 weeks gestation increasing thereafter again with pre-pregnancy values achieved by 12 weeks postpartum. Iron supplementation in non-diabetic and diabetic women had no significant effect upon the changes in serum concentration of either zinc or magnesium. These results suggest that the decrease in the concentrations of both elements is a normal physiological adjustment to pregnancy and that iron supplementation does not influence these changes.

Trace element metabolism in the fetus and neonate

The effects of trace metal nutrition on the fetus and neonate have been described. Since very little research has been done with the human fetus and neonate, much of our knowledge must be extrapolated from animal studies. In addition, most of the work centres around the effects of copper and zinc nutrition. Nutritional requirements (when known) for both enteral and total parenteral feeding of certain trace metals, as well as the bioavailability, have been discussed. Finally, methods of assessment of trace metal nutritional status have been discussed. These include direct measurement of metal concentrations and determination of biochemical indicators, such as metal-dependent enzyme activities--both of which are static indicators of nutritional status, and functional assessment of nutritional status which is a dynamic measure of trace metal nutrition and includes tests measuring the effects of metal nutrition on the function of cells, tissues, organs, and the host in general.

Assessment of trace element status

Biochemical and clinical investigations involving trace elements are made for the diagnosis of inherited or acquired deficiencies of essential trace elements and their treatment, to monitor the efficacy of the therapeutic administration of non-essential trace elements in order to achieve maximum clinical response with minimum toxicity, and for the early detection of excessive ingestion of non-essential toxic trace elements. The wide range of tests used to assess trace element status in these three areas of clinical importance is discussed with examples of essential and of toxic trace elements since therapeutic use of trace elements is discussed elsewhere in this issue. Particular attention is given to zinc, copper, selenium, lead and cadmium because the various tests used to assess the status of these elements encompass the principles of all currently available tests. Although trace element analysis of body fluids and tissues is the most useful and most commonly used method of assessment of trace element status, this is of limited value and no single test may be considered as ideal for any element. The provision of more detailed information from elemental analysis of cellular and subcellular fractions and of protein fractions from plasma leads inexorably to measurements of element-dependent enzymes, metalloproteins and of low molecular weight element-binding ligands. Even at this level of discrimination the choice of body tissue or tissue fluid for investigation is determined by the trace element and its principal metabolic targets.

Zinc, pregnancy and parturition

The role of zinc in the nutrition of pregnant women and its relations to prenatal growth and parturition are reviewed. Zinc deficiency (ZD) affects fetal growth and development both in experimental animals and in man. The teratogenicity of zinc deficiency was widely demonstrated in animals and is also evident in humans. Alcohol intoxication potentiates the effects of ZD in animals. Plasma zinc levels decrease during pregnancy and apparently an adequate and continuous intake of zinc is required for a normal embryonic development. The zinc content of amniotic fluid seems to be related with fetal growth but its value as an indicator of embryonic development is controversial. Zinc deficiency also affects adversely parturition. Mild zinc deficiency may affect a large number of pregnant women, being potentially harmful to the mother and the fetus. This situation requires the screening of high-risk groups, the definition of adequate dietary intakes for each population, and the supplementation with zinc when deficits are detected.

Zinc in the fetus and newborn

The growing fetus and infant are at risk of becoming deficient of zinc, an adequate supply of which is essential for normal growth and development. Mild maternal zinc depletion was strongly associated with intrauterine growth retardation. Low levels of zinc in maternal plasma and poor placental perfusion reduced the materno-fetal transfer of zinc. Mean maternal dietary intake of zinc was 60% recommended daily allowance and mothers of small-for-gestational-age (SGA) babies consumed significantly less zinc than mothers of appropriate-for-gestational-age babies. In addition, iron/folate supplements, which are often routinely prescribed during pregnancy, despite dietary intakes of iron and folate being adequate, significantly decreased the oral bio-availability of zinc in pregnant women. Zinc supplementation may be beneficial to women at risk of delivering SGA babies. Zinc requirements and interactions are also important to consider when designing mineral supplements for preterm babies, infant formulae and food fortification in developing countries.

Serum and lymphocyte, aluminum and nickel in chronic renal failure

In the past decade, aluminum has been recognized as a toxic metal in patients with chronic renal failure. It is, however, possible that other trace metals, such as nickel, may also have toxic actions in these patients. The plasma concentration of a metal, such as aluminum or nickel, may not provide a valid index of either tissue content or total body burden. In the study reported here, the aluminum and nickel content of lymphocytes was measured and compared with plasma concentrations in normal controls and patients with chronic renal failure. The findings suggest that lymphocytes may be of value as a nucleated 'tissue' for the assessment of trace metal status.

Non-protein bound zinc concentration in human plasma and amniotic fluid measured by ultrafiltration

Using an ultrafiltration technique, apparent non-protein bound (NPB) zinc concentrations in plasma were found to be 2.2 +/- 0.2 (SEM) microgram Zn/l (10 observations) in normal males, 1.6 +/- 0.3 (10) micrograms/l in normal females and 1.2 +/- 0.2 (10) micrograms/l in pregnant mothers during their 16th week of gestation. These values are about 0.2% of the total plasma zinc concentrations, at least five-fold less than previous estimates. In amniotic fluid, the NPB-zinc concentration was 12.6 +/- 0.4 (10) micrograms/l, 5-10 times that of normal plasma, though the total zinc concentration (100 +/- 30 micrograms/l) was only one tenth that of plasma. When plasma or amniotic fluid samples were ultrafiltered without precaution against CO2 loss, their NPB-zinc concentrations increased, suggesting that pH changes alter zinc binding. The low concentration of NPB-zinc in plasma explains the low urinary excretion of zinc observed by others and would be expected to restrict the entry of zinc into cells.

Nutrient intake of pregnant Asian women at Sorrento Maternity Hospital, Birmingham

The dietary intake of pregnant Asian women (that is originating from the Indian subcontinent) attending Sorrento Maternity Hospital in Birmingham was determined, using the weighed and recall techniques, at five-weekly intervals from 18 to 38 weeks of pregnancy. Mean energy intake of the group was 7.1 MJ (1700 kcal)/d. The intakes of most nutrients were substantially below those consumed by pregnant European women in Britain, a little below those of expectant Pakistani mothers in Islamabad, and about the same as those of expectant East London mothers. Intakes of vitamin D, total folate, vitamin B6, zinc and magnesium were particularly low. These observations suggest that a number of Asian women in Birmingham are likely to experience nutritional stress in pregnancy, and there is some anthropometric and biochemical evidence from Sorrento, published elsewhere (Bissenden et al. 1981), to support this. A possibly beneficial feature of the diet was a low sodium intake (2 g/d). Previous work at this hospital has noted a lower prevalence of hypertension in pregnant Asian women (Wharton et al. 1980; Bissenden et al. 1981).

Subethnic variation in the diets of Moslem, Sikh and Hindu pregnant women at Sorrento Maternity Hospital, Birmingham

The previous paper (Eaton et al. 1984) described the nutrient intake of pregnant Asian women attending Sorrento Maternity Hospital, Birmingham using the weighed and recall methods. The present paper describes the subethnic variation in nutrient intake by comparing the results from Pakistanis, Sikhs, Hindus and Bangladeshis and also describes food eaten by the pregnant women. Generally, Sikhs had the highest intake of most nutrients (mean energy 7.5 MJ (1800 kcal)/d) and the greatest variety of foods; they ate chapatti and paratha but few ate meat. Hindus had a very similar diet but more ate meat, chicken and rice. Pakistanis had an energy intake about 10% below that of the Sikhs and Hindus; meat was eaten, and intake of fruit, and therefore vitamin C, was quite large. Bangladeshis were the smallest women; they had the lowest intake of energy (mean energy 6.5 MJ (1555 kcal)/d) and most nutrients, except for protein, so that 15% of energy was provided by protein. Fish, rice and a low-fat intake were other features of their diet. From a nutritional standpoint, peoples coming from the Asian subcontinent should be divided into subethnic groups; the collective term 'Asian' is insufficient. It is not clear whether these differences have any effect on the life and health of the individuals. Comparison of groups does not suggest an obvious relationship between dietary intake and fetal growth; however, there is other evidence to implicate the possible role of deficiencies of protein, energy, zinc and pyridoxine. The results provide some support for the community nutritional policies of (a) offering vitamin D supplements to all pregnant Asian women and (b) fortifying bread with calcium, thiamin and nicotinic acid. There is probably no need to offer vitamin A and C supplements but they are harmless. Indications for iron supplementation are no different from those for white English women.

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.

Alterations in the postnatal development of the cerebellar cortex due to zinc deficiency. II. Impaired maturation of Purkinje cells

Zinc deficiency during the first 3 postnatal weeks retarded the maturation of Purkinje cells. The dendrites of the Purkinje cells of 21-day-old zinc-deficient (ZD) rats were reduced in size and had fewer branches. Somatic processes were found in 24% of the Purkinje cells of ZD animals. Only 3% of the Purkinje cells of normal animals had somatic processes. A basal polysomal mass in the Purkinje cells of 21-day-old ZD rats indicated that zinc deficiency impaired the cytoplasmic maturation of Purkinje cells. The development of the glial envestment of the dendrites and the maturation of climbing fibers also were retarded. Pair-fed controls were studied to control for the effects of inanition in the ZD dams. In the pups of pair-fed dams, undernutrition slightly impaired the growth of the dendrites but produced few qualitative changes in the maturation of the soma and climbing fibers. Somatic processes were found on 10% of the Purkinje cells of pair-fed animals. Thus, the findings in the ZD animals were not only caused by the decreased maternal food consumption but by zinc deficiency. The retarded maturation of Purkinje cells was related to the altered metabolism of Purkinje cells and to effects secondary to decreased numbers of parallel fibers.

The effect of steroid therapy on serum trace metal levels in sub-fertile males

The effect of 96 mg methylprednisolone on trace metals and hormone levels was measured in 13 males with sub-fertility associated with an antibody problem. Over a period of 5 days the serum zinc was significantly reduced (p less than 0.05) as was the serum testosterone (p less than 0.01). By contrast the luteinising hormone levels rose (p less than 0.01) within 3 days of administration of the steroid. The lability of serum zinc to the administration of steroids is further demonstrated by its significant fall (p less than 0.01) after 3 days of therapy. These results suggest an adreno-cortical control of zinc in serum.

The effect of iron supplements on pregnancy in rats given a low-zinc diet

Female Wistar rats were given an adequate-zinc (60 micrograms/g) or low-Zn (7 micrograms/g) diet for a minimum of 2 weeks and then mated. They were then either continued on the same diets (+Zn -Fe or -Zn -Fe) or given similar diets supplemented with four times the normal level of iron (+Zn +Fe or -Zn + Fe). The day before parturition they were killed and the fetuses removed and analysed. There were no differences in numbers of fetuses or the number of resorption sites. In the absence of Fe supplementation, the mean fetal wet weight was significantly less (P less than 0.05) in the low-Zn group but there was no effect of Zn in the two Fe-supplemented groups. The addition of Fe significantly decreased (P less than 0.05) the mean fetal wet weight in the adequate-Zn groups but had no effect in the low-Zn groups. There were no differences in fetal dry weight, fat, protein or DNA content. Both Fe-supplemented groups produced fetuses of higher Fe concentration (P less than 0.01), and mothers with higher bone Fe-concentration (P less than 0.01) compared with the non-supplemented groups. The low-Zn groups produced fetuses of lower Zn concentration (P less than 0.001) than the adequate-Zn groups but there was no effect on maternal bone Zn concentration. It was concluded that Fe-supplements did not adversely affect fetal growth from mothers given a low-Zn diet, but the addition of Zn to the unsupplemented diet increased fetal wet weight.(ABSTRACT TRUNCATED AT 250 WORDS)

Determination of zinc in erythrocytes, granulocytes and serum by flame atomic absorption spectrophotometry

Zinc was determined in granulocytes, erythrocytes and serum by flame atomic absorption spectrophotometry. Using a Teflon sampling cup, the sample volume for a single granulocyte zinc determination was reduced to 100 microliter. Zinc in serum and erythrocytes was measured by aspirating the sample at a rate of 5 ml/min. The total volume of blood used was 23-28 ml. The intra-assay coefficient of variation of the method for granulocytes was 0.01 and of the method for serum and erythrocytes 0.018. The corresponding inter-assay coefficient of variation was 0.037 and 0.03, respectively. Recovery of zinc determined by the method of aspirating the small volume (100 microliter) was 103% and by the method of aspirating 5 ml/min 97%. The coefficient of correlation between the two methods was r = 0.9968.

In vivo and in vitro studies of thymulin in marginally zinc-deficient mice

Thymulin (or serum thymic factor, FTS-Zn), a well-defined thymic hormone previously shown to be a nonapeptide binding the metal zinc, was studied in mice subjected to a long-term marginally Zn-deficient diet. In spite of the absence of thymic atrophy, we observed a significant decrease in the serum levels of thymulin as early as two months after the onset of treatment. However, these levels could be consistently restored after in vitro addition of ZnCl2. The analysis of thymuses from Zn-deficient mice showed that, despite the apparently normal network of epithelial cells, there was a progressive increase in the number of thymulin -containing cells (assessed by immunofluorescence with anti- thymulin monoclonal antibodies) that was already significant after two months of treatment. These results are in keeping with those of previous investigators, showing a specific, altered, thymic endocrine function following Zn deprivation. Nonetheless, our results strongly suggest that the nonactive Zn-deprived peptide is secreted under these experimental conditions. Furthermore, the fact that the augmented numbers of thymulin -containing cells were observed in the thymuses following a decrease in the peripheral thymulin (biologically active) brings further evidence for the existence of a feedback mechanism for the secretion of this hormone.

Leukocyte zinc in the assessment of zinc status

The problems of assessment of human zinc status are reviewed, with particular emphasis on the limitations to each of the current available measurements. The advantages and limitations of leukocytes are then described. Methods of preparation and potential problems in the assay for zinc are described in detail. The data so-far produced by this method are reviewed.