Maternal calcium supplementation and fetal bone mineralization

Altering maternal calcium and phosphorus dietary intake induces persistent sex-specific changes in the dentition of the offspring

BACKGROUND

The maternal diet is essential to offspring development, but the specific effects on tooth morphology are still unknown. The aim of this study was to evaluate the effects of altering maternal calcium (Ca) and phosphorus (P) supplementation during gestation and lactation on offspring dentition.

METHODS

Pregnant mice were fed an experimental diet containing a threefold increase in Ca and a threefold decrease in P compared to the standard mouse chow diet at embryonic Day 0.5 (E0.5). Offspring mice were maintained on standard or experimental diets from post-natal Day 0 to weaning, then fed control diets until 6 weeks of age. Six-week-old offspring heads were collected and scanned using micro-computed tomography. Dental morphometrics of offspring maxillary and mandibular first and third molars (n = 5-6 per diet/per sex) were determined. A two-way ANOVA test was employed to verify the existence of any significant differences between groups. The significance level was set at P < .05.

RESULTS

A two-way ANOVA revealed a statistically significant interaction between the effects of diet and sex on the upper and lower dentition. Moreover, experimental diet-fed female offspring exhibited smaller molars with shorter mesiodistal width and larger pulp chambers relative to controls, while experimental diet-fed male offspring possessed larger molars with wider mesiodistal width and smaller pulp chambers.

CONCLUSION

Our findings reveal that altering the maternal and offspring dietary Ca:P ratio during gestation, lactation and weaning led to significant, sex-specific changes in the offspring dentition. The differences in dentition appeared to be correlated with the sex-specific changes in the craniofacial skeleton.

Calcium Supplementation on Glucose Tolerance, Oxidative Stress, and Reproductive Outcomes of Diabetic Rats and Their Offspring

Diabetes mellitus increases the risk of obstetric complications, morbidity, and infant mortality. Controlled nutritional therapy with micronutrients has been employed. However, the effect of calcium (Ca2+) supplementation on diabetic pregnancy is unclear. We aimed to evaluate whether diabetic rats supplemented with Ca2+ during pregnancy present better glucose tolerance, redox status, embryonic and fetal development, newborn weight, and the prooxidant and antioxidant balance of male and female pups. For this, newborn rats received the beta-cytotoxic drug streptozotocin for inducing diabetes on the day of birth. In adulthood, these rats were mated and treated with Ca2+ twice a day from day 0 to day 20 of pregnancy. On day 17, the pregnant rats were submitted to the oral glucose tolerance test (OGTT). At the end of pregnancy, they were anesthetized and killed to collect blood and pancreas samples. The uterine horns were exposed for an evaluation of maternal reproductive outcomes and embryofetal development, and the offspring's liver samples were collected for redox status measurement. Nondiabetic and diabetic rats supplemented with Ca2+ showed no influence on glucose tolerance, redox status, insulin synthesis, serum calcium levels, and embryofetal losses. The reduced rate of newborns classified as adequate for gestational age (AGA) and higher rates of LGA (large) and small (LGA) newborns and higher -SH and GSH-Px antioxidant activities in female pups were observed in diabetic dams, regardless of supplementation. Thus, maternal supplementation caused no improvement in glucose tolerance, oxidative stress biomarkers, embryofetal growth and development, and antioxidants in pups from diabetic mothers.

Overview of Important Micronutrients Supplementation in Preterm Infants after Discharge: A Call for Consensus

Preterm infants have a lower level of nutrient body stores and immature body systems, resulting in a higher risk of malnutrition. Imbalanced complementary feeding could lead to further risk of nutritional deficits and excesses. However, evidence on their nutritional requirements following hospital discharge is limited. When planning complementary feeding, appropriate micronutrient intake should be considered for their critical role in supporting various body functions. This narrative review summarizes the need for iron, zinc, vitamin D, calcium, phosphate and long-chain polyunsaturated fatty acids (LCPUFAs) supplementation in preterm infants during complementary feeding. Regarding iron and vitamin D, the scientific community is reaching an agreement on supplementation in some categories of prematures. On the contrary, there is still not enough evidence to detail possible recommendations for LCPUFAs, zinc, calcium and phosphorus supplementation. However, these micronutrients are paramount for preterms' health: LCPUFAs can promote retinal and brain development while calcium and phosphorus supplementation is essential to prevent preterms' metabolic bone disease (MBD). Waiting for a consensus on these micronutrients, it is clear how the knowledge of the heterogeneity of the prematures population can help adjust the nutritional planning regarding the growth rate, comorbidities and comprehensive clinical history of the preterm infant.

Metabolic Bone Disease in Premature Neonates: An Unmet Challenge

Metabolic bone disease (MBD) is an important cause of morbidity in premature, very low birth weight (VLBW) and sick infants and, if left undiagnosed, may lead to structural deformities and spontaneous fractures. MBD is defined as impaired bone mineralization in a neonate with lower than expected bone mineral levels in either a fetus or a neonate of comparable gestational age and/or weight, coupled with biochemical abnormalities with or without accompanying radiological manifestations. MBD has been reported to occur in 16% to 40% of extremely low birth weight neonates and presents by 6-16 weeks after birth. Insufficient calcium and phosphorous stores during the phase of accelerated growth predispose to MBD in neonates along with the use of some medications such as caffeine or steroids, prolonged parenteral nutrition and chronic immobilization. Enhanced physical activity in preterm infants facilitates bone mineralization and weight gain. Biochemical abnormalities tend to worsen significantly, as the severity of disease progresses. These abnormalities may include hypocalcemia, hypophosphatemia, hyperphosphatasia and secondary hyperparathyroidism. In addition, urinary phosphate wasting and hypovitaminosis D can be additional complications. Conversely, biochemical abnormalities may not be accompanied by rachitic changes. Newer diagnostic modalities include non-invasive bone densitometry by quantitative ultrasound over the mid-tibial shaft. The management of MBD includes adequate calcium, phosphorous and vitamin D supplementation, along with optimum nutrition and physical activity. Similarly, preventive strategies for MBD should target nutritional enhancement in combination with enhanced physical activity. MBD usually results in preventable morbidity in preterm and VLBW neonates. Treatment consists of optimum nutritional supplementation and enhanced physical activity.

Safety and efficacy of supplements in pregnancy

Pregnancy is a time where expectant mothers often focus on their diet to improve their own health and to preserve the future health of their children. There is much conflicting information in the public domain about the safety and/or efficacy of nutritional supplements during pregnancy. Despite this, the market for supplements is growing. This review discusses the roles of critical nutrients in pregnancy and the available evidence on the use of supplements to reduce risks and improve maternal and fetal outcomes. Recommendations are made for pregnant women, taking into account safety data and tolerable upper intakes set for pregnant women. It is important for dieticians, nutritionists, physicians, and other healthcare providers to be able to offer accurate and evidence-based advice on supplement use in pregnancy. Routine supplementation may not be necessary for all, but individuals at risk are identified.

Longitudinal measures of maternal vitamin D and neonatal body composition

Background/Objectives

Vitamin D status has been associated with fetal growth and offspring’s bone mass in some observational studies. We characterize the trajectory of total maternal serum 25-hydroxyvitamin D [25(OH)D] concentration by race and examine whether vitamin D status is associated with neonatal anthropometry and body composition as assessed by dual energy X-ray absorptiometry (DXA).

Methods

Three longitudinal pregnancy samples from the Memphis site of the Calcium for Preeclampsia Prevention trial (1992-1995) were used. Racial differences in total 25(OH)D trajectories (n=343 women) were tested using an interaction term between blood draw gestational week and race in linear mixed-effects models. Linear regression and linear mixed-effects models estimated adjusted associations between total 25(OH)D concentration with neonatal anthropometry and body composition (n=252 with DXA), including interactions with infant sex and serum calcium.

Results

Total 25(OH)D concentration increased with gestational age but its trajectory over pregnancy did not differ between African-American and Caucasian women. Deficient maternal vitamin D (25(OH)D concentration <20 ng/ml) was associated with lower neonatal total bone mineral density (β −0.009 g/cm²; 95% CI −0.016, −0.002). Among male newborns, deficiency was also associated with lower lean mass (−217 g; −391, −43) and birthweight (−308 g; −540, −76). Deficient maternal vitamin D was also associated with lower ponderal index (β –2.3 kg/m³; 95% CI −4.0, −0.5) among those in the lowest calcium tertile.

Conclusion

Vitamin D deficiency during pregnancy is associated with lower bone density and smaller size at birth in certain subgroups suggesting its importance in fetal development.

Long-term effects of maternal calcium supplementation on childhood growth differ between males and females in a population accustomed to a low calcium intake

The importance of adequate calcium intakes for healthy growth and bone development has long been recognised. Recent evidence suggests that calcium supplementation may have sex-specific effects on bone growth in childhood. The aim was to describe the long-term effects of calcium supplementation in pregnant Gambian women with a low calcium intake (ISCRTN96502494) on offspring height, weight, bone and body composition in childhood, and whether the effects differ by sex. Children of mothers who participated in the original calcium supplementation trial were measured at age 8-12years using dual-energy X-ray absorptiometry and peripheral quantitative computed tomography. Linear models tested for sex*supplement interactions before and after adjusting for current age and size in early life. 447 children, aged 9.2(SD 0.9) years, were measured. Significant sex*supplement interactions (p<0.05) were observed for many of the anthropometric and bone outcomes, Females whose mothers received calcium (F-Ca) were shorter, lighter with smaller bones and less bone mineral than those whose mothers received placebo (F-P), differences (SE) ranged from height=-1.0 (0.5)% to hip BMC -5.5 (2.3)%. Males from mothers in the calcium group (M-Ca) had greater mid-upper arm circumference (MUAC) (+2.0 (1.0)%, p=0.05) and fat mass (+11.6 (5.1)%, p=0.02) and tended towards greater BMC and size than those whose mothers were in the placebo group (M-P). The differences in anthropometry and body composition were robust to adjustment for current height and weight, whereas all bone differences became non-significant. F-P were taller with more BMC than M-P, whereas F-Ca had similar sized bones and mineral content to M-Ca. Calcium supplementation of pregnant women with low calcium intakes altered the childhood trajectories of growth and bone and body composition development of their offspring in a sex-specific manner, resulting in slower growth among females compared to placebo and accelerated growth among males by age 8-12years.

Global Consensus Recommendations on Prevention and Management of Nutritional Rickets

BACKGROUND

Vitamin D and calcium deficiencies are common worldwide, causing nutritional rickets and osteomalacia, which have a major impact on health, growth, and development of infants, children, and adolescents; the consequences can be lethal or can last into adulthood. The goals of this evidence-based consensus document are to provide health care professionals with guidance for prevention, diagnosis, and management of nutritional rickets and to provide policy makers with a framework to work toward its eradication.

EVIDENCE

A systematic literature search examining the definition, diagnosis, treatment, and prevention of nutritional rickets in children was conducted. Evidence-based recommendations were developed using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system that describes the strength of the recommendation and the quality of supporting evidence.

PROCESS

Thirty-three nominated experts in pediatric endocrinology, pediatrics, nutrition, epidemiology, public health, and health economics evaluated the evidence on specific questions within five working groups. The consensus group, representing 11 international scientific organizations, participated in a multiday conference in May 2014 to reach a global evidence-based consensus.

RESULTS

This consensus document defines nutritional rickets and its diagnostic criteria and describes the clinical management of rickets and osteomalacia. Risk factors, particularly in mothers and infants, are ranked, and specific prevention recommendations including food fortification and supplementation are offered for both the clinical and public health contexts.

CONCLUSION

Rickets, osteomalacia, and vitamin D and calcium deficiencies are preventable global public health problems in infants, children, and adolescents. Implementation of international rickets prevention programs, including supplementation and food fortification, is urgently required.

Serial serum alkaline phosphatase as an early biomarker for osteopenia of prematurity

Metabolic bone disease of prematurity is a condition characterized by reduction in bone mineral content (osteopenia). It is a problem faced by very low birth weight (VLBW) infants because of lack of fetal mineralization during the last trimester. Our aim was to assess serum alkaline phosphatase (ALP) level as an early biomarker for osteopenia in premature infants and to estimate an optimal cutoff value of serum ALP at which osteopenia is detected radiologically in premature newborns.This prospective study was conducted on a cohort of 120 newborn infants of both sex of ≤34 weeks' gestational age and <1500 g birth weight. Two blood samples, from each infant on at least 2 consecutive weeks, were reported for calcium, phosphorus, and ALP. Evidence of osteopenia was evaluated radiologically by performing wrist/knee x-ray.Sixteen infants (13.3%) had evidence of osteopenia in x-ray, whereas 104 infants (86.7%) were nonosteopenic and all the osteopenic infants were <1000-g birth weight. Birth weight and gestational age were significantly inversely related to serum ALP levels. Both samples showed statistically significantly higher mean ALP level in osteopenic than nonosteopenics (P < 0.001, and P < 0.001 respectively). There was no constant value of serum ALP related to radiologic evidence of osteopenia. However, the optimal cutoff value of serum ALP at which osteopenia is detected is 500 IU/L with 100% sensitivity and 80.77% specificity.High levels of ALP can be considered a reliable biomarker to predict the status of bone mineralization and the need for radiological evaluation in premature infants particularly those <1000-g birth weight and <32 weeks' gestation.

Maternal Dietary Supplementation with Oligofructose-Enriched Inulin in Gestating/Lactating Rats Preserves Maternal Bone and Improves Bone Microarchitecture in Their Offspring

Nutrition during pregnancy and lactation could exert a key role not only on maternal bone, but also could influence the skeletal development of the offspring. This study was performed in rats to assess the relationship between maternal dietary intake of prebiotic oligofructose-enriched inulin and its role in bone turnover during gestation and lactation, as well as its effect on offspring peak bone mass/architecture during early adulthood. Rat dams were fed either with standard rodent diet (CC group), calcium-fortified diet (Ca group), or prebiotic oligofructose-enriched inulin supplemented diet (Pre group), during the second half of gestation and lactation. Bone mineral density (BMD) and content (BMC), as well as micro-structure of dams and offspring at different stages were analysed. Dams in the Pre group had significantly higher trabecular thickness (Tb.Th), trabecular bone volume fraction (BV/TV) and smaller specific bone surface (BS/BV) of the tibia in comparison with CC dams. The Pre group offspring during early adulthood had an increase of the lumbar vertebra BMD when compared with offspring of CC and Ca groups. The Pre group offspring also showed significant increase versus CC in cancellous and cortical structural parameters of the lumbar vertebra 4 such as Tb.Th, cortical BMD and decreased BS/BV. The results indicate that oligofructose-enriched inulin supplementation can be considered as a plausible nutritional option for protecting against maternal bone loss during gestation and lactation preventing bone fragility and for optimizing peak bone mass and architecture of the offspring in order to increase bone strength.

Global Consensus Recommendations on Prevention and Management of Nutritional Rickets

BACKGROUND

Vitamin D and calcium deficiencies are common worldwide, causing nutritional rickets and osteomalacia, which have a major impact on health, growth, and development of infants, children, and adolescents; the consequences can be lethal or can last into adulthood. The goals of this evidence-based consensus document are to provide health care professionals with guidance for prevention, diagnosis, and management of nutritional rickets and to provide policy makers with a framework to work toward its eradication.

EVIDENCE

A systematic literature search examining the definition, diagnosis, treatment, and prevention of nutritional rickets in children was conducted. Evidence-based recommendations were developed using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system that describe the strength of the recommendation and the quality of supporting evidence.

PROCESS

Thirty-three nominated experts in pediatric endocrinology, pediatrics, nutrition, epidemiology, public health, and health economics evaluated the evidence on specific questions within five working groups. The consensus group, representing 11 international scientific organizations, participated in a multiday conference in May 2014 to reach a global evidence-based consensus.

RESULTS

This consensus document defines nutritional rickets and its diagnostic criteria and describes the clinical management of rickets and osteomalacia. Risk factors, particularly in mothers and infants, are ranked, and specific prevention recommendations including food fortification and supplementation are offered for both the clinical and public health contexts.

CONCLUSION

Rickets, osteomalacia, and vitamin D and calcium deficiencies are preventable global public health problems in infants, children, and adolescents. Implementation of international rickets prevention programs, including supplementation and food fortification, is urgently required.

The Effect of Vitamin D and Calcium plus Vitamin D during Pregnancy on Pregnancy and Birth Outcomes: a Randomized Controlled Trial

INTRODUCTION

Evidence suggests a high prevalence of calcium and vitamin D deficiencies exists in both pregnant women and babies. Adequate intake of micronutrients has great importance especially during pregnancy and lactation period. Thus, the present study aimed at assessing the effect of vitamin D and calcium-vitamin D on pregnancy and birth outcomes (including duration of pregnancy, type of delivery and infant anthropometric indicators).

METHODS

A randomized, controlled, clinical, triple-blind trial conducted on 126 pregnant women referring to Tabriz health centers in 2013-14. Subjects were allocated into three groups using block randomization. Interventional groups received vitamin D, calcium-vitamin D and placebo pills daily for 60 days. ANCOVA and Chi-square tests were used for data analysis.

RESULTS

By controlling BMI before and during pregnancy, there were no significant differences between the group in average neonatal weight, height and head circumference, duration of pregnancy, type of delivery and gestational age at the time of delivery.

CONCLUSION

The results show that calcium-vitamin D and vitamin D have no effect on duration of pregnancy, type of delivery and infant anthropometric indicators.

Maternal 25-hydroxyvitamin D level and fetal bone growth assessed by ultrasound: a systematic review

OBJECTIVES

To assess systematically the role of maternal vitamin D levels in fetal bone growth.

METHODS

PubMed, EMBASE and Cochrane databases were searched using the search words [Vitamin D] in combination with [fetal, fetus, intrauterine, or prenatal AND growth, development, bone, femur, or humerus]; [crown-rump length]; or [ultrasonography, prenatal]. Criteria for inclusion in this systematic review were data on maternal serum 25-hydroxyvitamin D (25(OH)D) during pregnancy and measurement of fetal growth by ultrasound.

RESULTS

We identified 750 publications initially, from which five observational studies were selected for inclusion in the final review. The parameters studied were humerus length (HL) and femur length (FL) and their Z-scores, femoral volume, femoral distal metaphyseal cross-sectional area (CSA), femoral proximal metaphyseal diameter (PMD), femoral mid-shaft diameter and crown-rump length. In one study, 25(OH)D was associated directly with FL; in another study 25(OH)D only correlated with FL and HL Z-scores when calcium intake was insufficient. Two studies found no association between 25(OH)D and FL, but detected a direct association with femoral PMD, and an inverse relation with femoral distal metaphyseal CSA, respectively.

CONCLUSIONS

Observational studies investigating the role of maternal vitamin D levels in fetal bone growth are sparse. Their evidence suggests that low maternal 25(OH)D levels may affect fetal bone growth under certain circumstances, especially in cases of simultaneous low calcium intake. Further studies are necessary.

Prenatal calcium and vitamin D intake, and bone mass in later life

The aging population will result in an increasing burden of osteoporotic fractures, necessitating the identification of novel strategies for prevention. There is increasing recognition that factors in utero may influence bone mineral accrual, and, thus, osteoporosis risk. The role of calcium and vitamin D has received much attention in recent years, and in this review, we will survey available studies relating maternal calcium and vitamin D status during pregnancy to offspring bone development. The evidence base supporting a positive influence on intrauterine skeletal growth appears somewhat stronger for maternal 25(OH)-vitamin D concentration than for calcium intake, and the available data point toward the need for high-quality randomized controlled trials in order to inform public health policy. It is only with such a rigorous approach that it will be possible to delineate the optimal strategy for vitamin D supplementation in pregnancy in relation to offspring bone health.

Maternal calcium metabolic stress and fetal growth

BACKGROUND

Suboptimal maternal calcium intake and vitamin D status may or may not adversely influence fetal growth.

OBJECTIVE

It was hypothesized that maternal calcium metabolic stress in early pregnancy, rather than suboptimal calcium intake or insufficient vitamin D, influences the risk of small-for-gestational-age (SGA) births and other aspects of fetal growth. Stress to calcium metabolism was defined as elevated intact parathyroid hormone (PTH) (>62 pg/mL) accompanied by a very low calcium intake [<60% of the Estimated Average Requirement (EAR)] or insufficient 25-hydroxyvitamin D [25(OH)D] (<20 ng/mL).

DESIGN

This was a prospective cohort study of 1116 low-income and minority gravidae at entry to care of 13.8 ± 5.6 wk (mean ± SD).

RESULTS

The PTH concentration depended on circulating 25(OH)D and total calcium intake. When 25(OH)D was insufficient, even a high calcium intake (which equaled or exceeded the Recommended Dietary Allowance) was unable to maintain PTH or to moderate the proportion of patients with an elevated PTH. When examined one at a time, very low calcium intake (<60% of EAR), very low 25(OH)D (<12 ng/mL), and elevated PTH (>62 pg/mL) each had a small but significant association with birth weight. Elevated PTH was also related to birth length and risk of SGA birth. Elevated PTH accompanied by insufficient 25(OH)D or very low calcium intake was associated with a 2- to 3-fold increased risk of SGA birth and a significantly lower birth weight, birth length, and head circumference, even after women who developed preeclampsia were excluded. Infants born to gravidae with insufficient 25(OH)D or very low calcium intake without elevated PTH or with elevated PTH alone were unaffected.

CONCLUSION

Maternal calcium metabolic stress, rather than low calcium intake or insufficient vitamin D, has an adverse influence on fetal growth. This trial was registered at clinicaltrials.gov as NIH 0320070046.

New reference values for calcium

The nutrition societies of Germany, Austria and Switzerland are the joint editors of the 'reference values for nutrient intake'. They have revised the reference values for the intake of calcium and published them in June 2013. The reference values for the calcium intake for infants are derived from the calcium content of breast milk. For infants from 4 to <12 months of age, the calcium intake from solid foods is included in addition to the calcium intake from breast milk. Thus, the reference values for infants are estimated values; they are 220 mg/day for infants to <4 months and 330 mg/day for infants from 4 to <12 months of age. As a parameter for determining the calcium requirement in children and adolescents, calcium retention is taken into account. The average requirement is calculated by the factorial method. A balanced calcium metabolism is calculated based upon calcium balance studies and used as a parameter for the determination of the calcium requirement in adults. On the basis of the average requirement, recommended calcium intake levels for children, adolescents and adults are derived. Depending on age, the recommended calcium intake ranges between 600 mg/day for children aged 1 to <4 years and 1,200 mg/day for adolescents aged 13 to <19 years; for adults, it is 1,000 mg/day.

Role of calcium during pregnancy: maternal and fetal needs

Although the demand for additional calcium during pregnancy is recognized, the dietary reference intake for calcium was lowered for pregnant women in 1997 to amounts recommended for nonpregnant women (1,000 mg/day), and recently (November 2010) the Institute of Medicine report upheld the 1997 recommendation. It has been frequently reported that women of childbearing age do not consume the dietary reference intake for calcium and that calcium intake in the United States varies among ethnic groups. Women who chronically consume suboptimal amounts of calcium (<500 mg/day) may be at risk for increased bone loss during pregnancy. Women who begin pregnancy with adequate intake may not need additional calcium, but women with suboptimal intakes (<500 mg) may need additional amounts to meet both maternal and fetal bone requirements. The objective of this review is to elucidate the changes in calcium metabolism that occur during pregnancy as well as the effect of maternal calcium intake on both maternal and fetal outcomes.

Socioeconomic status and intake of energy and sodium are associated with calcium intake among pregnant women in Rafsanjan city, Iran

AIM

Calcium intake in developing countries is lower than that in developed countries. In Iran, inadequate calcium intake in the general population, especially among women, is a public health concern. This cross-sectional study examined the correlation between sociodemographic, obstetrical and lifestyle factors with calcium intake among pregnant women in Rafsanjan city, southeast Iran.

MATERIAL AND METHODS

A sample of 308 healthy pregnant women aged 18-35 years from seven urban health-care centers participated in the study. All women were measured for height and weight and interviewed for demographic and socioeconomic, obstetrical, lifestyle and dietary intake information while pre-pregnancy weight was obtained from prenatal record. Stepwise multiple regression was used to assess factors associated with calcium intake.

RESULTS

The mean daily calcium intake of women was 968.51±363.05mg/day and only 46.4% of the pregnant women met the dietary reference intakes of 1000 mg for calcium. Milk and milk products showed the greatest contribution to calcium intake (75.11%). Energy-adjusted calcium intake was positively associated with years of schooling (P<0.01), calorie (P<0.01) and energy-adjusted sodium (P<0.01) intakes.

CONCLUSION

This information would be useful in planning and developing appropriate strategies to improve calcium intake in pregnant women. Efforts to increase calcium intake in pregnant women should focus on promoting nutrient-dense food and making these foods available and accessible, particularly to socioeconomically deprived women.

Calcium availability influences litter size and sex ratio in white-footed mice (Peromyscus leucopus)

The production of offspring typically requires investment of resources derived from both the environment and maternal somatic reserves. As such, the availability of either of these types of resources has the potential to limit the degree to which resources are allocated to reproduction. Theory and empirical studies have argued that mothers modify reproductive performance relative to exogenous resource availability and maternal condition by adjusting size, number or sex of offspring produced. These relationships have classically been defined relative to availability of energy sources; however, in vertebrates, calcium also plays a critical role in offspring production, as a considerable amount of calcium is required to support the development of offspring skeleton(s). We tested whether the availability of calcium influences reproductive output by providing female white-footed mice with a low-calcium or standard diet from reproductive maturity to senescence. We then compared maternal skeletal condition and reproductive output, based on offspring mass, offspring number and litter sex ratio, between dietary treatments. Mothers on the low-calcium diet exhibited diminished skeletal condition at senescence and produced smaller and strongly female-biased litters. We show that skeletal condition and calcium intake can influence sex ratio and reproductive output following general theoretical models of resource partitioning during reproduction.

Maternal micronutrient restriction programs the body adiposity, adipocyte function and lipid metabolism in offspring: a review

Fetal growth is a complex process which depends both on the genetic makeup and intrauterine environment. Maternal nutrition during pregnancy is an important determinant of fetal growth. Adequate nutrient supply is required during pregnancy and lactation for the support of fetal/infant growth and development. Macro- and micronutrients are both important to sustain pregnancy and for appropriate growth of the fetus. While macronutrients provide energy and proteins for fetal growth, micronutrients play a major role in the metabolism of macronutrients, structural and cellular metabolism of the fetus. Discrepancies in maternal diet at different stages of foetal growth / offspring development can have pronounced influences on the health and well-being of the offspring. Indeed intrauterine growth restriction induced by nutrient insult can irreversibly modulate the endocrine/metabolic status of the fetus that leads to the development of adiposity and insulin resistance in its later life. Understanding the role of micronutrients during the development of fetus will provide insights into the probable underlying / associated mechanisms in the metabolic pathways of endocrine related complications. Keeping in view the modernized lifestyle and food habits that lead to the development of adiposity and world burden of obesity, this review focuses mainly on the role of maternal micronutrients in the foetal origins of adiposity.

Maternal vitamin D status and calcium intake interact to affect fetal skeletal growth in utero in pregnant adolescents

BACKGROUND

Maternal calcium intake and vitamin D status may affect fetal bone development.

OBJECTIVE

This study was designed to examine relations between maternal calcium intake, 25-hydroxyvitamin D [25(OH)D] status, and fetal bone growth across pregnancy.

DESIGN

This was a prospective longitudinal design. Maternal 25(OH)D, parathyroid hormone, and 1,25-dihydroxyvitamin D [1,25(OH)(2)D] were determined at midgestation (∼26 wk) and at delivery in 171 adolescents (≤ 18 y). Dietary recalls and fetal sonograms were performed up to 3 times across gestation, and fetal femur and humerus z scores were generated.

RESULTS

Fetal femur and humerus z scores and neonatal birth length were significantly greater (P < 0.03) in adolescents consuming ≥ 1050 mg than in those consuming <1050 mg Ca/d. Maternal 25(OH)D > 50 nmol/L was significantly positively associated with fetal femur and humerus z scores (P < 0.01). When maternal smoking, height, race, weight gain, and gestational age were controlled for, these relations remained significant. Interactions between calcium intake and 25(OH)D were evident. Calcium intake was associated with fetal femur z scores and birth length only when maternal 25(OH)D was ≤ 50 nmol/L (P < 0.05). Similarly, maternal 25(OH)D was associated with fetal femur and humerus z scores only when maternal calcium intake was <1050 mg/d (P < 0.03).

CONCLUSIONS

Optimal calcium intake and adequate maternal vitamin D status are both needed to maximize fetal bone growth. Interactions between these nutrients were evident when either calcium or vitamin D status was limited. Improving maternal calcium intake and/or vitamin D status during pregnancy may have a positive effect on fetal skeletal development in pregnant adolescents.

Calcium and bone metabolism disorders during pregnancy and lactation

Pregnancy and lactation cause a substantial increase in demand for calcium that is met by different maternal adaptations within each period. Intestinal calcium absorption more than doubles during pregnancy, whereas the maternal skeleton resorbs to provide most of the calcium content of breast milk during lactation. These maternal adaptations also affect the presentation, diagnosis, and management of disorders of calcium and bone metabolism. Although some women may experience fragility fractures as a consequence of pregnancy or lactation, for most women, parity and lactation do not affect the long-term risks of low bone density, osteoporosis, or fracture.

What are the risks and benefits to increasing dietary bone minerals and vitamin D intake in infants and small children?

Bone minerals and vitamin D are crucial for infants and small children. Human milk has little vitamin D, and supplemental vitamin D must be given to all infants either via drops or as contained in infant formula or foods. The calcium and phosphorus in human milk are adequate for infants in the first six months of life, with supplemental minerals coming from weaning foods after six months. Long-term benefits to providing bone minerals at greater levels than in human milk have not been shown. There is no evidence to support high-dose bone mineral supplementation or high-dose vitamin D supplementation in infancy, and controlled trials are needed before these can be advocated.

Calcium supplementation (other than for preventing or treating hypertension) for improving pregnancy and infant outcomes

BACKGROUND

Maternal nutrition during pregnancy is known to have an effect on fetal growth and development. It is recommended that women increase their calcium intake during pregnancy and lactation, although the recommended dosage varies among professionals. Currently, there is no consensus on the role of routine calcium supplementation for pregnant women other than for preventing or treating hypertension.

OBJECTIVES

To determine the effect of calcium supplementation on maternal, fetal and neonatal outcomes (other than for preventing or treating hypertension) as well as any possible side effects.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (17 March 2011).

SELECTION CRITERIA

We considered all published, unpublished and ongoing randomised controlled trials (RCTs) comparing maternal, fetal and neonatal outcomes in pregnant women who received calcium supplementation versus placebo or no treatment. We excluded quasi- and pseudo-RCTs.

DATA COLLECTION AND ANALYSIS

Two review authors identified studies for inclusion and extracted the data. Two review authors performed data analysis.

MAIN RESULTS

This review includes data from 21 studies (involving 16,602 women). There were no statistically significant differences between women who received calcium supplementation and those who did not in terms of reducing preterm births (less than 37 weeks' gestation) (risk ratio (RR) 0.90; 95% confidence interval (CI) 0.73 to 1.11; 12 studies, 15615 women; random-effects model) and also in less than 34 weeks' gestation (RR 1.11; 95% CI 0.84 to 1.46; three trials, 5145 women). There was no significant difference in infant low birth weight between the two groups (RR 0.91; 95% CI 0.72 to 1.16; four trials, 13449 infants; random-effects). However, compared to the control group, women in the calcium supplementation group gave birth to slightly heavier birth weight infants (mean difference (MD) 64.66 g; 95% CI 15.75 to 113.58; 19 trials, 8287 women; random-effects).

AUTHORS' CONCLUSIONS

Calcium supplementation is associated with a significant protective benefit in the prevention of pre-eclampsia, and should be used for this indication according to a previous review. This review indicates that there are no additional benefits for calcium supplementation in prevention of preterm birth or low infant birth weight. While there was a statistically significant difference of 80 g identified in mean infant birth weight, there was significant heterogeneity identified, and the clinical significance of this difference is uncertain.

Metabolic Bone Disease in preterm newborn: an update on nutritional issues

Osteopenia, a condition characterised by a reduction in bone mineral content, is a common disease of preterm babies between the tenth and sixteenth week of life. Prematurely born infants are deprived of the intrauterine supply of minerals affecting bone mineralization.The aetiology is multifactorial: inadequate nutrients intake (calcium, phosphorus and vitamin D), a prolonged period of total parenteral nutrition, immobilisation and the intake of some drugs.The diagnosis of metabolic bone disease is done by biochemical analysis: low serum levels of phosphorus and high levels of alkaline phosphatase are suggestive of metabolic bone disease. The disease can remain clinically silent or presents with symptoms and signs of rachitism depending on the severity of bone demineralisation.An early nutritional intervention can reduce both the prevalence and the severity of osteopenia.This article reviews the pathophysiology of foetal and neonatal bone metabolism, focuses on the nutrient requirements of premature babies and on the ways to early detect and treat osteopenia.

A Mediterranean dietary style improves calcium utilization in healthy male adolescents

OBJECTIVE

To examine the effects of consuming a diet based on the Mediterranean patterns on calcium availability and metabolism in male adolescents.

DESIGN

A longitudinal study divided into two periods: a 3-day basal period, during which the subjects (n = 20; 12.9 +/- 1.14 years) consumed their usual diet (basal diet, BD), and a 28-day nutritional intervention period, in which an intervention Mediterranean-type diet - was consumed (ID).

METHODS

Dietary calcium utilization was assessed by means of calcium intake in food and calcium output in feces and urine as measured by flame absorption spectrophotometry. In addition, markers of calcium metabolism (serum Ca, parathyroid hormone and total alkaline phosphatase) and bone resorption (urine deoxypiridinoline) were measured.

RESULTS

No differences in total calcium intake were found between the two diets, but food sources of dietary calcium varied significantly. Compared with the BD, the consumption of the ID resulted in significant increases in calcium absorption (approximately 40%, p = 0.04) and retention (approximately 80%, p = 0.008), and a considerable decrease in urinary calcium excretion (approximately 40%, p = 0.01).The variations observed in bone markers reflected a higher bone turnover rate after the ID consumption.

CONCLUSIONS

A varied diet based on Mediterranean diet patterns during adolescence greatly improves dietary calcium utilization, which may help to maximize the peak bone mass and prevent related diseases, such as osteoporosis.

Determination of mineral content in methanolic safflower (Carthamus tinctorius L.) seed extract and its effect on osteoblast markers

Safflower (Carthamus tinctorius L.) seeds are used as a folk medicine to enhance bone formation or to prevent osteoporosis in Korea. Therefore, the methanolic extract of safflower seeds (MESS) containing high mineral content, such as calcium (Ca), potassium (K) and phosphorous (P), was evaluated for the role on osteoblast (Ob) markers of Sprague-Dawley rats. In serum of 3 to 11 weeks (wks) old rats, both osteocalcin (OC) content and bone-specific alkaline phosphatase (B-ALP) activity increased to their maximum levels in 4–7 wks. Hence, 3 wks old rats were selected for 8 wks oral treatment of MESS, resulted in the significant increase of Ob markers in serum such as OC content (4–8 wks), B-ALP activity (1–2 wks) and insulin-like growth factor I (IGF-I) level (1 wk), and the growth parameter such as the length of femur (2–8 wks) and tibia (4 wks). On the basis of Pearson’s correlation coefficient, there were a moderate correlation between OC and B-ALP at 8 wks, a low correlation between OC and IGF-I at 1, 4 and 8 wks, a moderate correlation between OC and femur length at 1, 2 and 8 wks, and a moderate correlations between OC and tibia length at 1 and 8 wks of MESS-treated groups. The result reveals that the changes of OC correlated at low to moderate level with the changes of B-ALP activity, IGF-I content and femur and tibia length in the MESS-treatment period. On the other hand, there were a strong correlation between IGF-I and femur length at 2 wks and moderate correlation between IGF-I and tibia length at 1, 2 and 8 wks of MESS-treated groups. Therefore, the effect of MESS on bone formation likely appears to be mediated by IGF-I at the early stage of treatment.

Maternal nutrition, intrauterine programming and consequential risks in the offspring

It is traditionally believed that genetic susceptibility and adult faulty lifestyle lead to type 2 diabetes, a chronic non-communicable disease. The "Developmental Origins of Health and Disease" (DOHaD) model proposes that the susceptibility to type 2 diabetes originates in the intrauterine life by environmental fetal programming, further exaggerated by rapid childhood growth, i.e. a biphasic nutritional insult. Both fetal under nutrition (sometimes manifested as low birth weight) and over nutrition (the baby of a diabetic mother) increase the risk of future diabetes. The common characteristic of these two types of babies is their high adiposity. An imbalance in nutrition seems to play an important role, and micronutrients seem particularly important. Normal to high maternal folate status coupled with low vitamin B(12) status predicted higher adiposity and insulin resistance in Indian babies. Thus, 1-C (methyl) metabolism seems to play a key role in fetal programming. DOHaD represents a paradigm shift in the model for prevention of the chronic non-communicable diseases.

Bone mineral content at birth is determined both by birth weight and fetal growth pattern

Adult peak bone mass is related to birth weight, suggesting it could be affected by fetal growth pattern. Small-for-gestational-age (SGA) newborns have lower bone mineral content (BMC), but what about adapted-for-gestational-age (AGA) newborns with fetal growth restriction? The purpose of the study was to determine the respective role of birth weight and fetal growth pattern on BMC. Full-term newborns from SGA high-risk pregnancies were included (n = 185). Estimated fetal weight percentiles were measured monthly from mid-gestation to birth, and restricted fetal growth (FGR) was defined as a loss by more than 20 percentiles. BMC was measured at birth, using dual x-ray absorptiometry. Newborns were SGA (n = 56) or AGA (n = 129). Newborns with FGR (n = 111) were AGA (n = 71) or SGA (n = 41). BMC was significantly lower in SGA than AGA (1.48 +/- 0.02 vs. 1.87 +/- 0.04 g/cm) and lower when FGR irrespective of birth weight (1.66 g/cm +/- 0.03 vs. 1.89 g +/- 0.05). In multivariate analysis, FGR and SGA were significant and independent predictors of low BMC. In conclusion, fetal growth pattern affects BMC not only in SGA infants but also when birth weight is maintained in the normal range.

Nutrition and bone growth and development

The growth and development of the human skeleton requires an adequate supply of many different nutritional factors. Classical nutrient deficiencies are associated with stunting (e.g. energy, protein, Zn), rickets (e.g. vitamin D) and other bone abnormalities (e.g. Cu, Zn, vitamin C). In recent years there has been interest in the role nutrition may play in bone growth at intakes above those required to prevent classical deficiencies, particularly in relation to optimising peak bone mass and minimising osteoporosis risk. There is evidence to suggest that peak bone mass and later fracture risk are influenced by the pattern of growth in childhood and by nutritional exposures in utero, in infancy and during childhood and adolescence. Of the individual nutrients, particular attention has been paid to Ca, vitamin D, protein and P. There has also been interest in several food groups, particularly dairy products, fruit and vegetables and foods contributing to acid-base balance. However, it is not possible at the present time to define dietary reference values using bone health as a criterion, and the question of what type of diet constitutes the best support for optimal bone growth and development remains open. Prudent recommendations (Department of Health, 1998; World Health Organization/Food and Agriculture Organization, 2003) are the same as those for adults, i.e. to consume a Ca intake close to the reference nutrient intake, optimise vitamin D status through adequate summer sunshine exposure (and diet supplementation where appropriate), be physically active, have a body weight in the healthy range, restrict salt intake and consume plenty of fruit and vegetables.

Effects of Dietary Calcium Intervention on Adolescent Mothers and Newborns

OBJECTIVE

To evaluate the effects of dietary calcium (Ca) intervention on adolescent pregnant mothers and their newborns.

METHODS

Seventy-two pregnant adolescent mothers were randomized into one of 3 groups: control, orange juice fortified with calcium, and dairy. The orange juice and dairy groups were required to take more than 1,200 mg Ca. Calcium tablets were added for those not able to meet required Ca. Maternal and infant weight, length, and blood pressure (BP) were recorded. Maternal dietary records were evaluated. Mother's blood was drawn for serum Ca, phosphate (P), magnesium (Mg), and vitamin 25-hydroxyvitamin D (D). Cord blood was collected for serum Ca and D. Newborn total body Ca was determined.

RESULTS

All mothers were similar in weight, height, and BP. Mothers in the orange juice plus calcium and dairy groups had higher intakes of Ca (1,472 mg and 1,771 mg) than controls (862 mg). One half of the mothers in the orange juice plus calcium group required Ca tablets. Mothers in the dairy group had higher intakes of P, D, and Mg, higher serum folate and D, and higher cord D levels. Mothers in the orange juice plus calcium group had higher serum P but lower serum folate and D. Infants (3,517+/-273 g) in the dairy group were heavier than infants in the control (3,277+/-177 g) and orange juice plus calcium (3,292+/-165 g) groups. Infants in the dairy group had higher total body calcium than control infants.

CONCLUSION

Calcium diet supplemented with dairy products during adolescent pregnancy resulted in higher maternal vitamin D and folate serum levels and higher newborn weight and bone mineralization compared with controls.

Calcium supplementation during pregnancy and lactation: effects on the mother and the fetus

Calcium consumption is essential for bone development and maintenance throughout life, yet more than one half of the female population in the United States does not consume the recommended amount of calcium. Calcium intake is especially crucial during pregnancy and lactation because of the potential adverse effect on maternal bone health if maternal calcium stores are depleted. There is often a transient lowered bone mineral density and increased rate of bone resorption, with the greatest consequence during the third trimester and throughout lactation. Studies indicate that calcium consumption should be encouraged, especially during pregnancy and lactation, to replace maternal skeletal calcium stores that are depleted during these periods. Because the fetus in utero and the neonate through breast-feeding are dependent on maternal sources for the total calcium load, adequate maternal calcium intake also can affect fetal bone health positively. Proper calcium consumption can be attained through the diet by the consumption of dairy products or leafy greens (such as kale), the consumption of fortified foods, or by supplementation with widely available calcium-containing supplement products. Because many women experience heartburn during pregnancy, calcium-based antacids are ideal for providing heartburn relief, and they offer a calcium supplement to ensure maternal and fetal bone health, without the danger of adverse effects on the neonate.

Maternal and cord blood long-chain polyunsaturated fatty acids are predictive of bone mass at birth in healthy term-born infants

Long-chain polyunsaturated fatty acids (LC PUFA) are associated with bone mass in animals and human adults, yet no data exist for human infants. Thus, the objective of this study was to establish that LC PUFA status is associated with bone mass in healthy infants. Thirty mother-infant pairs were studied for LC PUFA status by measuring maternal and cord blood red blood cells (RBC) for arachidonic acid (AA), eicosapentaenoic acid (EPA), and DHA. Infant anthropometry and lumbar spine 1-4, femur and whole-body bone mineral content (BMC) were measured within 15 d of delivery. Maternal and infant LC PUFA were tested for their relationship to BMC using Pearson correlation and backward step-wise regression analyses. At birth, the average gestational age was 39.3+/-1.1 wk and body weight was 3433+/-430 g. Cord RBC AA was positively correlated with whole-body BMC, AA:EPA positively correlated with lumbar spine 1-4 BMC and femur BMC. Maternal RBC AA was positively correlated with whole-body BMC. After accounting for infant weight using regression, whole-body BMC was positively predicted by cord RBC AA but none of the maternal LC PUFA; lumbar spine 1-4 BMC was positively predicted by cord RBCAA:EPA ratio but negatively by maternal DHA; and femur BMC was not predicted by cord LC PUFA but was negatively predicted by maternal DHA. Imbalances among the n-6 and n-3 LC PUFA by term gestation are associated with lower bone mass, suggesting that the maternal diet should be balanced in n-6 and n-3 LC PUFA.

Calcium and bone metabolism during pregnancy and lactation

Pregnancy and lactation both place significant demands on the mother to provide sufficient calcium (among other minerals and nutrients) to the fetus and neonate. Despite facing similar demands for calcium during pregnancy and lactation, the maternal adaptations differ significantly between these two reproductive periods. Women lose 300 to 400 mg of calcium daily through breast milk, and this calcium demand is met by a 5-10% loss of skeletal mineral content during 6 months of exclusive lactation. Most importantly, the lost mineral is fully restored within a few months of weaning, such that women who have breastfed do not have a long-term deficit in skeletal mineral content. This article will review our present understanding of the adaptations in mineral metabolism that occur during pregnancy and lactation, and will focus on recent evidence that the breast itself plays a central role in regulating the adaptations during lactation.

Bone in the pregnant mother and newborn at birth

BACKGROUND

Changes in maternal bone during pregnancy may affect fetal bone mineralization.

ISSUES

The biphasic changes in maternal bone histology (temporary loss of cancellous bone in early pregnancy restored by term gestation) are consistent with corresponding blood biochemistry changes; increased bone resorption markers in the first trimester, while bone formation markers increased in the last trimester. Postpartum bone mineral density (BMD) by DEXA is increased at cortical bone and decreased at trabecular bone sites compared with prepregnancy values. The mean reduction of spine BMD is 3.5% from prepregnancy to immediate postpartum. Neonatal bone mineral content (BMC) is different by season of birth, low weight relative to gestation, and having a diabetic mother. Lower total body BMC and high bone resorption marker in winter vs. summer-born newborns was related to low vitamin D, indicating alterations of fetal bone metabolism by maternal D deficiency. Lower BMC and decreased bone formation marker in infants born small for gestational age than those born appropriate for gestation may relate to reduced transplacental mineral transfer. Low BMC in infants of diabetic mother was correlated inversely with poor control of maternal diabetes during early pregnancy.

CONCLUSIONS

During pregnancy, maternal bone mineral metabolism are changed, and influences on fetal bone mineralization occur in utero.

Contents of chemical elements in stomach during prenatal development: different age-dependent dynamical changes and their significance

AIM: To observe dynamic of different chemical elements in stomach tissue during fetal development.

METHODS: To determine contents of the 21 chemical elements in each stomach samples from fetus aging four to ten months. The content values were compared to those from adult tissue samples, and the values for each month group were also analyzed for dynamic changes.

RESULTS: Three representations were found regarding the relationship between contents of the elements and ages of the fetus, including the positive correlative (K), reversely correlative (Na, Ca, P, Al, Cu, Zn, Fe, Mn, Cr, Sr, Li, Cd, Ba, Se) and irrelevant groups (Mg, Co, Ni, V, Pb, Ti).

CONCLUSION: The chemical elements’ contents in stomach tissues were found to change dynamically with the stomach weights. The age-dependent representations for different chemical elements during the prenatal development may be of some significance for assessing development of fetal stomach and some chemical elements. The data may be helpful for the nutritional balance of fetus and mothers during prenatal development and even the perinatal stages.

Mobilization of lead from human bone tissue during pregnancy and lactation--a summary of long-term research

The skeleton is potential endogenous source of lead during pregnancy and lactation. We have undertaken a longitudinal investigation into the mobilization of lead from the human maternal skeleton to determine whether lead is mobilized from the maternal skeleton during pregnancy and lactation, and if so, when and how much is released. Subjects in the study were migrants to Australia (n=15) whose skeletal lead isotopic composition (endogenous lead) was different to that prevailing in the Australian environment (exogenous lead). This migrant cohort was compared with 6 multi-generational Australian controls. Biological and environmental samples were taken pre-pregnancy where possible, throughout pregnancy and postpartum for at least 6 months. Newly-born infants of the migrant and Australian mothers were monitored for 6 months. Blood lead concentrations for the migrant mothers ranged from 1.5 to 20 microg/dl (geometric mean 2.8) and for Australian mothers ranged from 1.9 to 4.3 microg/dl (geometric mean 2.9). There was minimal change in lead isotopic composition of the Australian pregnant controls although there were increases of approximately 40% in blood lead concentration in 3 of 6 cases during the postpartum period and from 0 to 12% in the other 3. In the migrant pregnant subjects, the geometric mean skeletal lead contribution to blood lead using the isotopic composition was approximately 33% (range 10-88%) for 14 subjects using a revised estimate for exogenous lead. Skeletal contribution to blood lead during the postpartum period was significantly greater than during pregnancy (P<0.001). The skeletal contributions to blood lead are higher and the changes are more consistent in those subjects who conceived within 100 days of arrival in Australia compared with those who conceived longer than 100 days. In the migrant subjects, changes in blood lead concentration during pregnancy and postpartum varied from subject to subject with an overall 20% increase; the increases during the postpartum period were greater than during pregnancy (P<0.001). It was estimated that the amount of maternal skeletal lead mobilized during pregnancy and transferred to the infant via cord blood averaged approximately 79%. The increased skeletal contribution to blood lead is attributed to a low daily calcium intake of approximately 500 mgCa/day, a condition which was present in both migrant and Australian subjects. An ongoing clinical trial is providing a new cohort with calcium supplements. A summary of other aspects of the study is included and covers: additional flux released from the skeleton during pregnancy and postpartum; XRF bone lead results; urinary excretion of lead during pregnancy and postpartum; dietary contribution to blood lead in female adults and children; comparison of rates of exchange of lead in blood of newly-born infants and mothers; relationships of lead in breast milk to lead in blood, urine and diet of the infant and mother; changes in blood lead after cessation of breastfeeding; urinary lead isotopes during pregnancy and postpartum indicate no preferential partitioning of endogenous lead into plasma; a comparison of some aspects of the nonhuman primate and human pregnancy studies.

Dietary intakes of selected elements from longitudinal 6-day duplicate diets for pregnant and nonpregnant subjects and elemental concentrations of breast milk and infant formula

As part of a longitudinal investigation into mobilization of lead from the maternal skeleton during pregnancy and lactation, we have determined the daily intake of selected elements (hereafter called micronutrients) for various subjects and compared these intakes with recommended and/or published intakes, especially those of the United States, through the U.S. National Health and Nutrition Examination Survey (NHANES). We also sought to ascertain whether there was any seasonal effect in the diets. Six-day duplicate diets were collected from 15 pregnant and 16 nonpregnant migrants to Australia, 6 pregnant Australian control subjects, and 8 children of nonpregnant migrants (6 to 11 years). Samples of breast milk and infant formula were also analyzed. Blended samples were analyzed by inductively coupled plasma mass spectrometry for the elements Ca, Cu, Fe, Mg, P, K, Na, Zn, Ba, Sr, and Pb. Daily intakes of micronutrients were only about half of the daily intake estimated for non-Hispanic white females and infants in the U.S. NHANES III. Estimates of daily intakes from breast milk were also considerably lower for the migrant and Australian infants compared with the values extracted from tables of food composition and dietary recall for non-Hispanic white infants in the U.S. NHANES III. For example, Ca was a factor of approximately 3 times lower, Fe approximately 50, and Zn approximately 4. We consider our estimates a reliable indication of the daily intakes for several reasons, including the collection of up to nine quarterly collections of 6-day duplicate diets and retention of subjects in a longitudinal prospective study. The low intakes of the essential elements such as Ca, Fe, and Zn in all these population groups are of potential concern from a public health viewpoint.

Micronutrients in women's health and immune function

Lawrence J. Machlin's contributions to elucidating the roles of nutrients in optimizing human health included the support of research in the areas of women's health and immune function. Several essential nutrients have been shown to affect women's health throughout the different life stages. Symptoms of premenstrual syndrome affect the vast majority of menstruating women, and calcium supplementation significantly reduces physical and emotional symptoms. Premenstrual syndrome in fact might be a predictor of osteoporosis induced by low calcium intake. Periconceptional multivitamin supplementation has reduced the risk of serious birth defects, premature delivery, and low birth weight by 50% and improved maternal health during pregnancy. Micronutrients of particular importance for prevention of adverse pregnancy outcomes are folic acid, zinc, and iron. However, if the preterm delivery is caused by preeclampsia, then data suggest that calcium supplementation and high doses of vitamins C and E significantly reduce that risk. Well-controlled studies consistently have shown that calcium supplementation, with or without vitamin D, significantly reduces the risk of hip fracture. Antioxidants such as vitamins C and E have been shown to reduce the risk of fracture in women smokers. As in the rapidly growing embryo, the immune system includes rapidly multiplying cells whose functions are dramatically affected by an individual's micronutrient status. Multivitamins have been shown to enhance many aspects of immune response, and antioxidant micronutrients consistently have been found to enhance lymphocyte-proliferative responses and skin-test responses, especially in the elderly.