Trace minerals in pregnancy 1. Copper and zinc

Association of selenium, zinc and copper concentrations during pregnancy with birth weight: A systematic review and meta-analysis

BACKGROUND

Normal fetal growth is associated with maternal nutrition. Trace elements play important roles in fetus growth. This review aims to provide a summary of the literature evaluating the relation between selenium, zinc and copper levels during pregnancy with birth weight.

METHOD

A systematic literature search was conducted in Medline database (PubMed), Scopus, Web of science and Google scholar up to September 2020. Fifty observational studies were included in the final analyses. The desired pooled effect size was considered as standardized mean differences with 95 % CI or correlation. Cochran's Q statistic was used to test the heterogeneity between the included studies (I²).

RESULT

A significant differences were found between pooled standardized mean differences (SMD) of umbilical cord blood copper levels in small-for-gestational age birth weight (SGA) and appropriate-for-gestational age birth weight (AGA) (SMD: 0.34 μg/L, 95 % CI: 0.13 to 0.56). There was a significant pooled correlation between umbilical cord blood selenium concentrations and birth weight (r: 0.08, 95 % CI: 0.01 to 0.16). A significant pooled correlation was found between umbilical cord blood zinc concentrations and birth weight (r: 0.09, 95 % CI: 0.04 to 0.15), with significant heterogeneity (I² % = 0.63). There was significant positive association between maternal blood zinc concentrations and birth weight.

CONCLUSION

Findings showed the association of trace elements including selenium, zinc and copper during pregnancy with birth weight. There was significant correlation between umbilical cord and maternal blood selenium and zinc levels with birth weight. The umbilical cord blood copper levels in SGA birth weight was higher than copper levels in AGA birth weight.

Magnitude of Zinc Deficiency among Nulliparous Nonpregnant Women in a Rural Community of Haryana State, India

Zinc deficiency during pregnancy affects the outcome of pregnancy. A high prevalence of zinc deficiency (55.5%) has been reported among pregnant women. It is not known whether pregnancy leads to zinc deficiency due to the increased fetal needs or whether the women are zinc deficient when they become pregnant. No data are available on the zinc status of nulliparous nonpregnant women from India. To assess the magnitude of zinc deficiency among nulliparous nonpregnant women in a rural community of Haryana State, India. A community-based cross-sectional survey was conducted in six villages of a rural area in a district of Haryana State, India. All nulliparous nonpregnant women aged 18 years or over who were willing to participate in the study were enrolled. Each woman was questioned about her age, socioeconomic status, and dietary pattern with the use of a pretested semistructured questionnaire. Blood from the antecubital vein was drawn to assess the serum zinc levels using an atomic absorption spectrophotometer. Serum zinc levels less than 70.0 μg/dl were considered to indicate zinc deficiency. The dietary intakes of zinc, protein, and calories were assessed by the 24-hour dietary recall method. Two hundred eighty-eight nulliparous nonpregnant women were enrolled. Forty-one percent had zinc deficiency, and 75.7%, 1.4%, and 7.3% of the women consumed less than 50% of the recommended intake of zinc, protein, and calories, respectively. Women who consumed less than 50% of the recommended intake of calories (1,875 kcal) were at a 4.9 times higher risk of zinc deficiency than women who consumed more than 50% of the recommended intake. A high prevalence of zinc deficiency was found among the nulliparous nonpregnant women in the area studied.

A prospective study of selenium concentration and risk of preeclampsia in pregnant Iranian women: a nested case-control study

Preeclampsia remains a leading cause of maternal and perinatal mortality and morbidity worldwide; however, its specific etiology still remains obscure. Some studies implicate poor maternal selenium status predisposing the mother to preeclampsia. This study was designed to determine changes in plasma selenium levels in women having preeclampsia as compared with those with normal pregnancy. In a nested case-control study, 650 normal primigravida in their first 24-28 weeks participated in the study. After 3 months of follow-up of all subjects, blood selenium levels were measured in 38 women presenting consecutively with preeclampsia and in 38 women having a normal pregnancy by atomic absorption spectrophotometry. Birth outcomes were recorded, such as gestational age at delivery, height, weight, birth head circumflex and 1-min Apgar score. Preeclampsia affects about 5.84 % of pregnancies, and in our study, there were no significant differences in age, anthropometric indices, and family history of preeclampsia between the preeclamptic and control groups. The selenium concentrations in plasma in women with preeclampsia were significantly lower as compared with those in women with normal pregnancy (70.63 ± 21.41 versus 82.03 ± 15.54 μg/L, p < 0.05). Being in the bottom tertile of selenium concentration (less than 62.2 μg/L) was associated with greater risk of preeclampsia in pregnant women. The reduced selenium in the maternal circulations observed in the preeclamptic mothers support the hypothesis that insufficient selenium concentration may be a contributing factor to the pathophysiological mechanisms associated with preeclampsia, and optimizing the dietary selenium intake through supplementation could produce demonstrable clinical benefits.

Effect of breeding season and pregnancy status on serum progesterone, sodium, potassium, copper and iron of estrous synchronized Aradi goat does

Eighteen out of 88 estrous synchronized Aradi goat does were randomly chosen to be bled during May-July (Out breeding season, n = 9) and during September-December (Within breeding season, n = 9). Estrous synchronization was applied by using a control internal drug release (CIDR) as a reproductive management regimen throughout the year. Nineteen days after CIDR insertion, a 500 IU eCG was injected (i.m.) and CIDR was removed. Does were subjected to fertile bucks 48-60 h after CIDR removal. Jugular blood samples were collected in non-heparinized Vacutainer tubes at 0 h just before CIDR insertion, every 3 days during CIDR insert, at day of CIDR removal, at incidence of estrus and mating, at day 1, 8 and 30 post mating. Data on pregnancy were recorded and serum levels of progesterone (P), sodium (Na), potassium (K), copper (Cu) and iron (Fe) were determined. Progesterone concentration was higher (p < 0.05) within (2.85 ± 0.15 ng/ml) than outside (2.37 ± 0.13 ng/ml) the breeding season. Pregnant does exhibited higher (p < 0.05) levels of progesterone (2.76 ± 0.17 ng/ml) than non-pregnant does (2.37 ± 0.10 ng/ml). No significant interaction was found between season and pregnancy status on progesterone concentration. A typical progesterone profile was found during treatment days, as levels of P increased during CIDR insertion and declined at CIDR removal and thereafter. Neither breeding season nor pregnancy status affected Na(+) concentration. Contrariwise, mean levels of K(+) was higher (p < 0.05) outside (148.34 ± 3.91 mg/L) than within (136.27 ± 3.91 mg/L) the breeding season. Pregnancy status did not influence K concentration. Sodium/potassium (Na(+)/K(+)) ratio was significantly (p < 0.01) higher within (30.29 ± 0.44) than outside (27.62 ± 0.44) the breeding season. On the contrary, pregnancy status did not affect this ratio. Iron concentrations neither affected by season nor pregnancy. Likewise, Cu concentrations were not affected by season, however Cu levels were higher (p < 0.05) in pregnant (147.75 ± 7.24 μg/L) than in non-pregnant (127.31 ± 5.03 μg/L) does.

The role of calcium, magnesium, and zinc in pre-eclampsia

Pre-eclampsia is the most common medical complication of pregnancy associated with increased maternal and infant mortality and morbidity. Its exact etiology is not known, although several evidences indicate that various elements might play an important role in pre-eclampsia. This study was carried out to analyze and to compare the concentration of calcium, magnesium, and zinc in the serum of women with pre-eclampsia and in normal pregnant women. Fifty clinically diagnosed patients with pre-eclampsia (25 with mild and 25 with severe pre-eclampsia) and 50 normal pregnant controls were enrolled in this study. The serum calcium, magnesium, and zinc levels were estimated with an atomic absorption spectrophotometer. The mean serum levels of calcium, magnesium, and zinc in normal pregnant group were 2.45 +/- 0.18 mmol/L, 0.79 +/- 0.13 mmol/L, and 15.64 +/- 2.4 micromol/L, respectively, while in mild pre-eclamptic group, these were 2.12 +/- 0.15 mmol/L, 0.67 +/- 0.14 mmol/L, and 12.72 +/- 1.7 micromol/L, respectively. Serum levels in severe pre-eclamptic group were 1.94 +/- 0.09 mmol/L, 0.62 +/- 0.11 mmol/L, and 12.04 +/- 1.4 micromol/L, respectively. These results indicate that reduction in serum levels of calcium, magnesium, and zinc during pregnancy might be possible contributors in etiology of pre-eclampsia, and supplementation of these elements to diet may be of value to prevent pre-eclampsia.

Prenatal and perinatal zinc restriction: effects on body composition, glucose tolerance and insulin response in rat offspring

Maternal undernutrition increases the risk of adult chronic diseases, such as obesity and type 2 diabetes. This study evaluated the effect of maternal zinc restriction in predisposing the offspring to adiposity and altered insulin response in later life. Seventy-day-old female Wistar/NIN rats received a control (ZnC) or zinc-restricted (ZnR) diet for 2 weeks. Following mating with control males, a subgroup of the ZnR dams were rehabilitated with ZnC diet from parturition. Half the offspring born to the remaining ZnR dams were weaned onto the ZnC diet and the other half continued on the ZnR diet throughout their life. Body composition, glucose tolerance, insulin response and plasma lipid profile were assessed in male and female offspring at 3 and 6 months of age. The ZnR offspring weighed less than control offspring at birth and weaning and continued so until 6 months of age. Rehabilitation regimens corrected the body weights of male but not female offspring. Maternal zinc restriction increased the percentage of body fat and decreased lean mass, fat-free mass and fasting plasma insulin levels in both male and female offspring at 6 months of age. Also, glucose-induced insulin secretion was decreased in female but not male offspring. Despite the differences in fasting insulin and the area under the curve for insulin, the fasting glucose and the area under the curve for glucose were in general comparable among offspring of different groups. Rehabilitation from parturition or weaning partly corrected the changes in the percentage of body fat but had no such effect on other parameters. Changes in plasma lipid profile were inconsistent among the offspring of different groups. Thus chronic maternal zinc restriction altered the body composition and impaired the glucose-induced insulin secretion in the offspring.

Serum zinc, copper, selenium, calcium, and magnesium levels in pregnant and non-pregnant women in Gondar, Northwest Ethiopia

Pregnant women in developing countries are vulnerable to multiple micronutrient deficiencies. Studies assessing serum levels of the micronutrients and magnitude of their deficiencies are very scarce in African subjects. This study was aimed at determining serum levels of micronutrients in 375 pregnant (42 HIV seropositive) and 76 non-pregnant women (20 HIV seropositive) who visited the University of Gondar Hospital, Gondar, Ethiopia. Serum concentrations of zinc,\ copper, selenium, calcium, and magnesium were determined using an inductively coupled plasma mass spectrometer. Irrespective of HIV serostatus, pregnant women had significantly higher serum concentrations of copper and copper/zinc ratio and significantly lower magnesium compared to those in non-pregnant women (P < 0.05). Except for selenium, which was significantly lower in HIV-seropositive pregnant women (P < 0.05), the mean serum concentrations of zinc, copper, calcium, and magnesium were not significantly different between pregnant women by HIV serostatus. The prevalence of deficiency in zinc, magnesium, selenium, and calcium in the pregnant women, irrespective of their HIV serostatus, was 66.7%, 25.6%, 21.9%, and 9.3%, respectively. The magnitude of deficiency in zinc, magnesium, and selenium was significantly higher in HIV seropositive pregnant women (76.2%, 52.4%, and 45.2%) than that in HIV-seronegative pregnant women (65.5%, 22.2%, and 18.9%) and in HIV-seronegative non-pregnant women (42.9%, 8.1%, and 30.4%; P < 0.05). Deficiency in one, two, three, or four mineral elements was observed in 44.8%, 14.4%, 9.9%, and 5.1% of the pregnant women, respectively. Only 25.9% of the pregnant women and 44.7% of the non-pregnant women were not deficient in any of the micronutrients. The high prevalence of micronutrient deficiencies in pregnant and non-pregnant women in Gondar, Ethiopia warrants the need for strategies on prevention and control of the deficiencies.

Influence of cadmium and copper on tissue element levels of pregnant rats

In the current study, we examined the effects of Cd on Cd, Cu, Zn and Fe levels in placenta and maternal and fetal plasma and tissues, the placental weight, total fetal and maternal body weights, and fetal and maternal tissue weights during pregnancy. A total of 21 adult female rats were treated during gestation with drinking water containing one of the following: 70 mg/L of CdCl2, a combination of 70 mg/L of CdCl2 and 70 mg/L of CuSO4, or no addition (control). Placenta Cu and Fe levels, fetal liver and kidney Cu levels, and fetal liver tissue weights were lower in the group administered Cd than in the control group. Also, Cd levels in the placenta, maternal and fetal liver, and maternal kidney were higher in the group treated with Cd than in controls. In the group administered both Cd and Cu, fetal body and tissue weights did not change, but Cd levels in the placenta, maternal and fetal liver, and maternal kidneys were higher than in controls. Zn and Fe levels in the maternal kidney and fetal liver were also lower in this group. Cd exposure during pregnancy resulted in Cd accumulation in maternal and fetal tissues during pregnancy and a decrease in the total weight of fetuses, and the combination of Cd and Cu caused some changes in the both maternal and fetal levels of Cu, Zn, and Fe, but it did not cause changes in the total fetal body weight or the weights of individual tissues.

Direct analysis of human blood (mothers and newborns) by energy dispersive X-ray fluorescence

This work is an application of energy dispersive X-ray fluorescence (EDXRF) as analytical technique for trace element determination in human tissues. Potassium (K), calcium (Ca), iron (Fe), copper (Cu), zinc (Zn), bromine (Br), rubidium (Rb) and lead (Pb) were determined directly in blood samples from 66 mothers at delivery after full-term pregnancies. The corresponding 66 cord-blood samples of the newborns were also analysed, in order to find element correlations between maternal and newborn blood at birth. The studied samples were obtained from mothers aged between 15 and 39 years old, the gestational age being between 35 and 41 weeks and the newborns' weight between 2.310 and 4.310 kg. Samples were lyophilised and analysed without any chemical treatment. Very low levels of Pb were found both in maternal and fetal cord blood samples. Cu values ranged from 3 to 13 microg g-1, both for mothers and children. A correlation between Cu and Fe concentrations in maternal and fetal cord blood was found. Zn is considered as one of the key elements in newborn health. Concentrations between 10 and 40 microg g-1 were measured. A positive correlation between Br levels in mothers and children was observed. Positive correlations for mothers were observed between Zn and Rb as well as K and Fe. The corresponding correlations in fetal cord blood samples were not observed, however positive correlations were found between Ca and K; Cu and Fe. The mean concentrations for each element were similar in maternal and in fetal cord blood, except for Cu and Zn, being higher in maternal samples. No correlations between element concentrations and pathologies of the mothers were observed.

Prevalence of multiple micronutrient deficiencies amongst pregnant women in a rural area of Haryana

Deficiencies of micronutrients (zinc, iron, folic acid and iodine) during pregnancy are known causes of Low Birth Weight (LBW). Studies have documented status of one or two micronutrients amongst pregnant women (PW). However, no attempt has been made to concurrently assess the prevalence of multiple micronutrient deficiencies and the factors associated with them amongst PW.

OBJECTIVE

The present study was undertaken to assess the prevalence of multiple micronutrient deficiencies amongst PW in a rural area.

METHODS

A community based cross sectional survey was conducted in six villages of a rural area of district Faridabad in Haryana state, India during November 2000 and October 2001. All PW aged 18 years or more, with pregnancy duration of more than 28 weeks were enrolled. Data were collected on socio-economic status and other demographic parameters. Serum zinc, copper and magnesium levels were estimated by utilizing the Atomic absorption spectrophotometry (AAS); serum ferritin and folate was estimated by Enzyme Linked Immuno Sorbent Assay (ELISA) method and the Radio-Immuno Assay (RIA) method, respectively and serum thyroid stimulating hormone (TSH) level was estimated by the Abbot AxSYM System. Serum zinc, copper, magnesium, ferritin, and folate levels less than 70.0 microg/dl, 80.0 microg/dl, 1.80 mg/dl, 15 ng/ml, and 3 ng/ml, respectively were considered as indicative of deficiency for respective micronutrients. The TSH levels of 4.670 and more indicated iodine deficiency status. Dietary intake of micronutrients was assessed utilizing 1-day 24-hour dietary recall methodology. Food consumption pattern was assessed utilizing the food frequency questionnaire methodology.

RESULTS

Nearly 73.5, 2.7, 43.6, 73.4, 26.3, and 6.4 percent PW were deficient in zinc, copper, magnesium, iron, folic acid and iodine, respectively. The highest concurrent prevalence of two, three, four and five micronutrient deficiency was of zinc and iron (54.9%); zinc, magnesium and iron (25.6%); zinc, magnesium, iron and folic acid (9.3%) and zinc, magnesium, iron, folic acid and iodine (0.8%), respectively. No pregnant woman was found to have concomitant deficiencies of all the six micronutrients. Dietary intake data revealed an inadequate nutrient intake. Over 19% PW were consuming less than 50% of the recommended calories. Similarly, 99, 86.2, 75.4, 23.6, 3.9 percent of the PW were consuming less than 50% of the recommended folic acid, zinc, iron, copper, and magnesium. The consumption of food groups rich in micronutrients (pulses, vegetables, fruits, nuts and oil seeds, animal foods) was infrequent. Univariate and Multivariate logistic regression analysis revealed that low dietary intake of nutrients, low frequency of consumption of food groups rich in micronutrients and increased reproductive cycles with short interpregnancy intervals were important factors leading to micronutrient deficiencies.

CONCLUSION

There was a high prevalence of micronutrient deficiencies amongst the PW of the area, possibly due to the poor dietary intake of food and low frequency of consumption of food groups rich in micronutrients. The concurrent prevalence of two, three, four and five micronutrient deficiencies were common.

Role of trace elements zinc, copper and magnesium during pregnancy and its outcome

Trace element deficiencies have been documented to play an important role in determination of the fetal outcome. Pregnant women in developing countries have been reported to consume diets with a lower density of minerals and vitamins. Deficiencies of trace elements like zinc, copper and magnesium have been implicated in various reproductive events like infertility, pregnancy wastage, congenital anomalies, pregnancy induced hypertension, placental abruption, premature rupture of membranes, still births and low birth weight. The present review article highlights the important of role played by zinc, copper and magnesium during pregnancy and its outcome. The role of individual trace elements and in combination with other trace elements has not been completely documented. There is a need to undertake further studies in this field.

Serum levels of zinc and copper in hydatidiform mole

OBJECTIVE

The aim of this study was to identify any association between serum levels of trace elements zinc and copper and development of hydatidiform mole.

STUDY DESIGN

Blood samples of 35 patients with complete hydatidiform mole and 34 pregnant women controls were evaluated for serum levels of zinc and copper. Student's t-test was used for comparison of mean values of serum zinc and copper and for demographic variables. p< or =0.05 was considered statistically significant.

RESULTS

Levels of zinc in serum were found to be significantly higher in hydatidiform mole patients than controls (86.3 vs. 68.7 microg/l, p=0.027). Serum copper levels were significantly lower in hydatidiform mole patients than controls (123.8 vs. 147.8 microg/l, p=0.039; Table 2).

CONCLUSION

This is the first study in the English scientific literature reporting higher serum levels of zinc and lower serum levels of copper associated with complete hydatidiform mole.

Effect of gestational age on cord blood plasma copper, zinc, magnesium and albumin

BACKGROUND

The transport of essential trace elements from mother to fetus varies throughout gestation, and the role of transport proteins in the neonate and the mother may change during pregnancy. Magnesium, often used as tocolytic agent, may reach the fetus and appear in cord blood at higher than normal concentrations.

AIMS

To determine cord blood plasma zinc, copper and magnesium concentrations, as well as plasma albumin in premature and full-term newborns, and correlate these values with those of maternal blood plasma at birth. Also, to examine whether cord blood plasma concentration of these elements varies with gestational age.

SUBJECTS

The 35 mother-infant pairs included: 11 in the 38-42-week gestational age (GA), 9 in the 34-37-week GA, 11 in the 29-33-week GA group and 4 in the 24-28-week GA. Magnesium for tocolysis was given to five of the mothers in the 29-33-week GA cohort and two of the women giving birth at 24-28-week GA.

RESULTS

Trend analysis showed that while cord plasma zinc decreased with GA at birth, the reverse was observed for copper. There were no differences with GA either in maternal plasma zinc or copper. However, maternal ceruloplasmin tended to decrease with GA (P=0.0174). Maternal and cord blood plasma magnesium exhibited a strong correlation (r=0.942, P<0.001), as well as between cord plasma magnesium and zinc (r=0.448, P<0.01).

CONCLUSIONS

While the vigorous mother-to-fetus uphill zinc transfer is clear throughout the last trimester, copper remains in cord blood plasma at much lower concentrations than in the mother, suggesting that prematurity may place the newborn infant at a greater risk than the term infant to copper deficiency. This situation, together with a reduced synthesis in the fetus of the transport protein ceruloplasmin, creates another potential challenge in the nutritional support of the premature infant.

Modulation of copper/zinc superoxide dismutase expression and activity with in vitro differentiation of human villous cytotrophoblasts

Due to the role of oxygen free radicals in trophoblast cell differentiation, we used the in vitro model of villous cytotrophoblast differentiation into the syncytiotrophoblast to investigate the modulation of the key antioxidant enzyme copper/zinc superoxide dismutase (SOD-1) in the human trophoblast during pregnancy. Cytotrophoblast cells were isolated from first-trimester and term placentae. SOD-1 mRNA levels were determined using real-time quantitative polymerase chain reaction, protein levels were determined by immunoblotting with a specific monoclonal antibody, and oxidoreductase activity was measured during syncytiotrophoblast formation in vitro. Interestingly, SOD-1 protein levels fell significantly (P< 0.001) during syncytiotrophoblast formation but no corresponding change in enzyme activity was observed. This apparent discrepancy may be related to different amounts of SOD-1 co-factor in the two cell types. Indeed the level of copper was significantly higher (P< 0.05) in syncytiotrophoblast as compared with cytotrophoblast. SOD-1 mRNA levels remained stable during cytotrophoblast differentiation. SOD-1 expression and activity were similar in cytotrophoblast cells isolated from first-trimester and term placentae, and in the differentiated syncytiotrophoblast in vitro. These results underline the need to determine SOD-1 protein expression and activity simultaneously in order to gain a better knowledge of its role in human trophoblast cell differentiation.

Determinants of maternal zinc status during pregnancy

Zinc deficiency in pregnant experimental animals limits fetal growth and, if severe, causes teratogenic anomalies. Although the data from human studies are not consistent, similar outcomes have been observed and were associated with poor maternal zinc status. This paper reviews humans studies of zinc status and pregnancy outcome, describes the physiologic adjustments in zinc utilization during pregnancy to meet fetal needs while maintaining maternal status, and identifies dietary and environmental conditions that may override those physiologic adjustments and put the health of the mother and fetus at risk. Adjustments in intestinal zinc absorption appear to be the primary means by which zinc retention is increased to meet fetal demands. However, transfer of sufficient zinc to the fetus is dependent on maintenance of normal maternal serum zinc concentrations. Conditions that could interfere with zinc absorption include intake of cereal-based diets that are high in phytate, high intakes of supplemental iron, or any gastrointestinal disease. Conditions that may alter maternal plasma zinc concentrations and the transport of zinc to the fetus include smoking, alcohol abuse, and an acute stress response to infection or trauma. Supplemental zinc may be prudent for women with poor gastrointestinal function or with any of these conditions during pregnancy.

Maternal plasma zinc concentrations and pregnancy outcome

BACKGROUND

There is no consensus in the literature as to whether maternal zinc nutriture is associated with pregnancy outcome or fetal growth.

OBJECTIVE

We evaluated the associations between plasma zinc concentrations during pregnancy and various measures of pregnancy outcome and neonatal conditions at birth.

DESIGN

We measured zinc concentrations in plasma samples obtained at a mean of 16 wk of gestation (range: 6-34 wk) from 3448 women who were screened for a trial designed to evaluate the effect of zinc supplementation on fetal growth. Subjects were from low socioeconomic backgrounds and attended a public health clinic for their prenatal care. Plasma zinc concentrations were compared with pregnancy outcome, including complications during pregnancy and delivery, and anthropometric measures and Apgar scores of neonates.

RESULTS

Plasma zinc concentrations declined as gestation progressed. After plasma zinc concentrations were adjusted for gestational age, they were not significantly associated with any measure of pregnancy outcome or neonatal condition.

CONCLUSION

We conclude that plasma zinc concentrations during the late first trimester to the early third trimester do not predict pregnancy outcomes in women of a low socioeconomic background.

Combined effect of high-fat diet and copper deficiency during gestation on fetal copper status in the rat

We have previously shown that a low-copper (Cu) diet produced alterations in placental Cu transport and fetal Cu stores. Because Cu deficiency has been associated with lipid deposition in rat dam liver, we hypothesized that a high fat intake, a prevalent dietary habit in many populations, may worsen fetal Cu status and its closely linked iron (Fe) deposits. Pregnant rats were fed one of four diets during the second half of gestation: NFNCu: normal fat (7%), normal Cu (6 mg/kg); HFNCu: high fat (21%), normal Cu; NFLCu: normal fat, low Cu (0.6 mg/kg), and HFLCu: high fat, low Cu. One day before delivery, dams were anesthetized, and maternal as well as fetal plasma and tissues were obtained. Maternal, fetal, and placental weights were indistinguishable regardless of the group. Dam plasma Cu and placental Cu were lower in both LCu groups than in the NFNCu or the HFNCu groups. However, fetal plasma Cu was similar in all treatment groups. Dam and fetal liver Cu stores were reduced in the LCu groups compared to the NCu groups. This resulted in lower fetal/maternal liver Cu ratios in the NFLCu (1.79+/-0.14, p < 0.05) and HFLCu (1.59+/-0.21, p < 0.05) as compared to the NFNCu (4.12+/-0.44) and the HFNCu (4.15+/-0.27). Dam liver Fe was higher in the NFNCu than in HFNCu group (1.10+/-0.8 vs. 0.89+/-0.06 micromol/g, p < 0.05); fetal liver Fe from HFNCu and NFLCu dams was lower than that from NFNCu fetuses (NFNCu: 2.42+/-0.14; HFNCu: 1.92+/-0.15, p < 0.05; NFLCu: 1.81+/-0.10, p < 0.01). Fetuses of the HFLCu group had a lower heart Fe than the NFNCu group (0.56+/-0.03 vs. 44.0+/-3.0 microg/g, p < 0.01). These data indicate that a maternal high-fat diet can potentially aggravate the effects of Cu deficiency by further altering fetal Cu and Fe tissue stores.

Mineral composition of meconium: effect of prematurity

OBJECTIVES

We hypothesized that the concentration of major essential mineral elements in meconium correlate with gestational age (GA) or birth weight. To verify this premise we determined the concentration in meconium of calcium, magnesium, phosphorus, copper, zinc, iron, and manganese.

METHODS

Thirty-four appropriate for age singleton infants without major congenital anomalies were divided into four GA groups (in weeks): 24 to 28; 29 to 33; 34 to 37; 38 to 42, or in birth weight groups (in g): < 1500; 1500-1999; 2000-2499; > or = 2500. Meconium was collected until the appearance of transitional stools and lyophilized for analysis.

RESULTS

When adjusted for birth weight, the concentrations of calcium, copper, iron and phosphorus were higher in the meconium of 24 to 28 week GA infants than in those of the 38 to 42 week GA newborns. Birth weight adjusted copper concentration was highest in the 29 to 33 week GA group, while the remaining elements did not change across the range of GA. Meconium copper concentration in infants born with < 2000 g was higher than in those born with a weight > or = 2500 g.

CONCLUSIONS

These results could serve as normative data of a noninvasive examination of the mineral nutritional "history" of the fetus, and, eventually, to better evaluate possible neonatal deficiencies in infants with intrauterine growth retardation or other types of complicated intrauterine courses.

Placental copper transport in rats: effects of elevated dietary zinc on fetal copper, iron and metallothionein

We hypothesized that the competition between zinc (Zn) and copper (Cu) during fetal accretion of copper could be discriminated at either the dam-to-placenta or placenta-to-fetus stage. This premise was tested by feeding dams a high Zn diet (1000 mg/kg, HZn) during the second half of gestation. One day before delivery, dams were anesthetized, fetuses removed and both maternal and fetal tissues and plasma obtained and assayed. Other rats were fed a normal Zn concentration diet (32.4 mg/kg, ND) throughout pregnancy. There were significantly lower fetal liver Cu concentrations and greater plasma Fe concentrations, but not plasma Cu concentrations or liver Fe concentrations in the HZn group. Both dam and fetal Zn liver concentrations were greater in the HZn than in the ND group. Plasma Cu levels were lower in the HZn-fed than in the ND-fed dams. Placental tissue from the HZn litters had a greater concentration of Zn and Fe than did the ND group, whereas no effect was noted for Cu concentration. Metallothionein (MT) levels were elevated in dam livers and placenta in the HZn group, but there were no differences in fetal liver MT. The dynamic assessment of placental transport was conducted by injecting 2.5 mg/kg Cu acetate intravenously into dams of both groups. Sequential samplings of dam and fetal blood and placentas were taken from 0 to 60 min. After the Cu bolus, there was a consistently higher plasma Cu concentration in the HZn than in the ND dams, but no alteration in the concentration of Cu in the placenta or fetal plasma. This study indicates that placental Cu uptake is not affected by a high Zn diet in the dam. In addition, the greater Zn concentration in the placenta of HZn than in ND litters results in abnormal fetal Cu, Fe and Zn concentrations, suggesting that an imbalanced maternal mineral consumption is deleterious to normal divalent metal accretion.

Placental copper transport in the rat. III: Interaction between copper and iron in maternal protein deficiency

Copper (Cu) and iron (Fe) metabolism are linked in the haematopoietic process. There is also considerable evidence of a linkage between protein intake and mineral sufficiency. The present study tested the hypothesis that a low protein diet during the second half of gestation in the rat alters Cu and Fe transport across the placenta and affects the Cu and Fe status of the fetus. Pregnant rats were fed a normal commercial diet the first half of gestation, and then assigned either a 20 per cent protein (NP) or a 4 per cent protein diet (LP) during the second half of gestation. One day before delivery, rats were anaesthetized, fetuses removed and dam tissues and plasma obtained. Other pregnant rats were injected i.v. with 2.5 mg/kg Cu acetate and sequential samples of dam blood, fetal blood and placentae were taken from 0 to 60 min. The LP diet produced generalized maternal hypoproteinaemia, and although there was no difference in fetal plasma albumin, there was a generalized fetal hypoproteinaemia as well. Fetal haematocrit (Hct) of the LP litters was lower than that of the NP group, but dam Hct was unchanged. Dam plasma Fe and Cu showed no differences between diets. Dam liver Cu was unaltered but liver Fe stores were elevated significantly. Before and after a Cu bolus, the LP placentae retained Cu to a greater extent than those of the NP placentae. Fetal liver Cu and Fe were elevated in the LP litters compared to the NP group. In conclusion, the LP diet in the dam during the second half of gestation was associated with fetal anaemia, hypoproteinaemia, and increased Cu and Fe accumulation in fetal liver. The higher concentration of Cu and Fe retained in LP placentae during gestation, and confirmed in the Cu challenge, suggest that Cu and Fe delivery to the fetus is related to placental concentration and that maternal protein malnutrition is a regulatory factor in fetal mineral homeostasis.

Placental copper transport in the rat. II: Effect of maternal copper deficiency

Copper (Cu) placental transport presents a steep downhill gradient from mother to fetus. This process could be altered by low-molecular-weight (LMW) ligands and maternal Cu deficiency. We compared the ratio of Cu transfer from dam-to-fetus in Cu-deficient (CuDf) and Cu-sufficient (CuSf) rats in the last day of gestation. Anaesthetized dams were iv injected 79 mumol/kg (5 mg/kg) of either Cu acetate [Cu (AcO)2]; Cu+L-histidine, 1:10. [Cu(His)10]; Cu-(glycyl-glycyl-L-histidine) [Cu(GGH)], or saline. Dam and fetal blood, as well as placentae were obtained at 0, 10, 20, 40 and 60 min. At time 0, CuDf dams had lower plasma Cu than CuSf dams (8.3 +/- 1.2 versus 26.7 +/- 1.1 mumol/l), but CuDf fetuses plasma Cu was unchanged. This resulted in a more favourable mean fetal: maternal plasma Cu ratio in the CuDf fetuses (0.61) than in the CuSf fetuses (0.21). Dam plasma Cu was unaffected by the chemical form of Cu injected. In CuDf fetuses lower plasma Cu was observed with Cu(GGH) and Cu (His)10 at 20 min than in the CuSf. In the presence of these LMW ligands CuDf placentae retained more Cu than those of the CuSf group. CuDf was associated ultrastructurally with extensive lipid deposition in dam hepatocytes and, to a lesser extent, in CuDf fetal liver. These results indicate that in CuDf, LMW ligands increase placental uptake of Cu, without improving placenta-fetus transport. Although the rat fetus is well adapted to intrauterine CuDf, it may also be susceptible to hepatic lipid infiltration when the dam is CuDf.

Relationship between soil zinc, dietary zinc and zinc nutritional status of humans

The effect of consumption of the staple food grown in soil zinc deficient area on zinc nutritional status of human beings was investigated. One village each from an area which has been classified under >75%, 25-50% and 50-75% soil zinc deficiency was selected for the study from Andhra Pradesh. Thirty families from each village were selected and the zinc content of soil, rice (grown in that soil) and serum (of people consuming the same rice) of the selected subjects was estimated. Food and nutrient intake of the respondents were calculated by using diet survey. Heights and weights of children of selected families were taken to assess the relationship between soil zinc levels and growth. Results show that the soil zinc deficiency has an impact on the zinc levels of rice grown in the same soil. However, serum zinc levels of adults and growth of children seem to be influenced by protein content and source of protein in the diet in addition to zinc levels of the diet.

The effects of low dietary copper intake during pregnancy on physiological fluids and reproductive performance of first-litter gilts

Seven pairs of first littermate gilts were used to study the influence of low copper supply and pregnancy on physiological fluids and reproductive performance of first-litter gilts. They were fed semi-purified diets containing either 2.13 or 12.25 micrograms/kg of Cu from 30 days of gestation through two weeks of lactation. Low-Cu gilts had lower plasma Cu in early- and mid- gestation and farrowed piglets with lower plasma Cu and higher plasma Zn concentrations (p < 0.05). Plasma Fe and Mn concentrations were not affected by Cu supply (p > 0.05). Plasma Cu and Fe levels of newborn piglets were lower than those of their dams (p < 0.05) but this was not true for plasma Zn and Mn (p > 0.05). Low-Cu gilts had lower Cu and higher Zn content in colostrum and also lower Cu in milk than control gilts (p < 0.05). No significant differences were found in Fe and Mn levels in colostrum and milk between the two treatments (p > 0.05). Colostrum was richer in Cu and Zn than milk (p < 0.05) but not in Fe and Mn (p > 0.05). The low-Cu diet did not affect (p > 0.05) weight changes during pregnancy. The duration of parturition was shorter for low-Cu than for control gilts (3.19h vs. 5.71h, p < 0.05). Control gilts farrowed larger litters than low-Cu gilts (9.71 vs. 7.57 piglets, p < 0.05). There were no significant differences in live litter weights at birth, one wk. or two wks. of age (p > 0.05). The results indicated that a low-Cu diet and pregnancy had some effect on plasma, colostrum and milk mineral concentrations, as well as on litter size of gilts. An interaction between Cu and Zn was found.