Relationship between blood lead concentration and dietary intakes of infants from 3 to 12 months of age

Data from a study of mother-infant pairs of low socioeconomic status living in Albany County, NY, were analyzed to determine the influence of diet and nutrition on the blood lead level of infants during the first year of life. Children's diets were assessed at 3-month intervals using a 24-h diet recall as reported by the primary caregiver. The potential impact of dietary consumption of protein, iron, zinc, calcium, vitamin D, and fat, as well as serum vitamin D and ferritin on blood lead levels at 6 and 12 months of age was examined with multivariable statistical analyses, controlling for other influences on lead levels. Neonates' blood lead levels were low at birth (geometric mean=1.6 microg/dL), and none were elevated (> or = 10 microg/dL). By 12 months, the mean blood lead for this sample was 5.1 microg/dL, and 18% of the sample had an elevated blood lead level. We observed significant inverse relationships between infants' 6-month lead level and their intake of zinc, iron, and calcium. At 12 months, low iron intake continued to be associated with higher lead levels, although zinc and calcium did not. Protein had a paradoxical effect, being associated with lower lead at 6 months, but higher lead at 12 months. Serum vitamin D and ferritin were not associated with lead levels, nor was vitamin supplement use. The results reported here emphasize the value of key minerals in the diet to reduce lead absorption during early infancy.     

Effect of dietary calcium on blood lead concentrations in occupationally exposed and nonexposed workers

Workers exposed to lead may benefit from a calcium-rich diet, since calcium competes with lead for intestinal absorption. We studied the effect of dietary calcium on blood lead levels. We assessed blood lead levels, dietary intake of calcium, smoking and alcohol consumption, and anthropometric and demographic data in 56 workers exposed to lead and 90 workers without such exposure. Mean intake of dietary calcium was 775 ± 370 mg/day in the nonexposed workers and 858 ± 423 mg/day in the exposed workers. Occupational lead exposure explained nearly 90% of the variance in blood lead levels of the entire cohort. Smoking and alcohol intake also showed significant associations with blood lead levels, but their combined effect was less than 2%. When the exposed and nonexposed workers were considered separately, no association was found between blood lead levels and calcium intake. The amount of calcium in the diet does not influence blood lead levels. Further studies are warranted to determine whether dietary calcium influences blood lead levels in exposed and nonexposed workers in other settings and in subjects with lower intakes of calcium. Am. J. Ind. Med. 34:512–516, 1998. © 1998 Wiley-Liss, Inc.     

Nutritional and physiological status of U.S. national figure skaters

This study assessed the nutrient intake, body composition and biochemical indices of National Figure Skating Championship competitors. Four-day diet records, fasting blood samples, and anthropometric measurements were obtained 2 months after the National Championships from 41 figure skaters 11-18 years of age. Energy, carbohydrate, fat, dietary fiber and cholesterol intake were significantly lower compared to the NHANES III averages for adolescents in the U.S. In general, the mean intakes for most vitamins except vitamin D and E were above the recommended intake. But the athletes had lower intakes of vitamin E and B12, and higher intakes of vitamin C, and thiamin (females only) compared with NHANES III. The mean intakes of magnesium, zinc, and iodine by the male skaters were below the recommended levels, as were the mean intakes of calcium, iron, phosphorus, magnesium, and zinc by the female skaters. Also, the number of servings from vegetable, fruit, dairy, and meat groups were below the recommended levels. Biochemical indices of nutritional status were within normal limits for all skaters. But plasma electrolyte concentrations were indicative of potential dehydration status. The results suggest there is a need to develop dietary intervention and educational programs targeted at promoting optimal nutrient and fluid intakes by these athletes to maintain performance and improve long-term health status.     

儿童血铅水平与钙铁锌关系探讨

目的:探讨儿童血铅水平与钙、铁、锌的相互关系。方法:采用原子吸收石墨炉法和火焰法,分别测定我院门诊1056名患儿的血铅和钙、铁、锌水平,并进行相关分析。结果:1056名儿童中,平均血铅水平为59.357μg/L,铅中毒发生率为17.1%,回归和相关分析显示,儿童血铅与血钙、锌水平差异有显著性(P<0.05),呈负相关关系。结论:儿童铅中毒可导致血钙、锌水平下降。     

Anthropometric and dietary survey of elderly Chinese.

The study was conducted to provide reference values of anthropometry and dietary intakes of elderly Chinese aged greater than or equal to 70 years and to investigate differences between urban and rural groups. A total of 441 subjects comprising 260 urban elderly (126 men and 134 women) and 181 rural elderly (83 men and 98 women) participated in the anthropometric study. One hundred subjects (50 men and 50 women) from both urban and rural locations were selected randomly from the anthropometric cohort for dietary survey using the method of diet recall. For both men and women, the urban elderly had significantly higher intakes of protein, fat, calcium, iron, retinol, thiamin, riboflavin and nicotinic acid than did the rural elderly. Significant sexual differences were also observed: men had higher intakes of total energy and three macronutrients than women. Both regional and sexual differences in anthropometry (but not blood pressure) seemed to be consistent with the results of the dietary survey. Positive correlations were found between systolic blood pressure and the ratio waist:hip circumference for both men and women. As a marker of adipose tissue distribution, it seemed that this ratio was more predictive of high blood pressure than body-weight.     

Cross-sectional study of blood lead effects on iron status in Korean lead workers

OBJECTIVE: This study assessed the iron status of Korean male lead workers by measuring the dietary iron intake and biochemical indices, and tested the hypothesis that a high blood lead level is associated with impaired iron function, which results in higher prevalence of iron deficiency when the route of exposure is not the gastrointestinal tract. METHODS: One hundred eighteen lead workers and 42 non-lead workers were recruited from mandatory annual health surveillance sites for industrial workers. Blood lead, hemoglobin, and hematocrit levels were evaluated as hematologic parameters, and serum iron concentrations, total iron-binding capacity, and percentage of transferrin saturation were evaluated as iron-status parameters. Dietary iron intake was assessed by a 24-h recall method. RESULTS: Lead workers had significantly lower hemoglobin, hematocrit, serum iron levels, percentage of transferrin saturation, and dietary iron intake than did non-lead workers, and they had significantly higher (P < 0.01) total iron-binding capacity. The occurrence of iron-deficiency cases, as assessed by hematocrit values, was significantly higher (P < 0.001) in lead workers than in non-lead workers, and the prevalence of iron deficiency was associated with high blood lead levels (P = 0.033). The dietary iron intake was inversely associated with zinc protoporphyrin (P = 0.032). CONCLUSIONS: This study confirmed the adverse effects of high blood lead levels on hematologic pathways and the effectiveness of dietary iron intake as a secondary preventive intervention against lead toxicity. To promote health and to prevent toxic effects of lead exposure in Korean lead workers, an adequate intake of dietary iron is strongly recommended.     

Dietary macro- and micronutrient intakes of nonsupplemented pre- and postmenopausal women with a perspective on menopause-associated diseases.

OBJECTIVES: To assess the dietary intakes and diet quality of menopausal women relative to premenopausal women, and to determine whether their diets are compatible with reducing risks of cardiovascular disease (CVD) and osteoporosis. DESIGN: Cross-sectional study using 3-day food records and anthropometric measurements. Subjects Thirty apparently healthy, nonoestrogen using and nonsupplemented women menopausal since 3-5 years and 30 well-matched premenopausal women. Outcome measures Nutrient intakes, diet nutrient density, body mass index (BMI), waist circumference, waist-to-hip ratio and serum oestradiol. RESULTS: Energy intake and body weight of pre- and postmenopausal women were comparable. Their BMI, waist circumference and waist-to-hip ratios were within healthy ranges. The diet of postmenopausal women was compatible (less total lipids and saturated fatty acids; more fibres, antioxidant vitamins and potassium) with North American nutritional recommendations linked to cardiovascular health. Their dietary iron intakes exceeded their reduced physiological need, which may jeopardize their cardiovascular system. Their calcium and vitamin D intakes were far below recommendations for healthy bones. Five other nutrients were also suboptimal. Phosphorus intake (high in both groups) correlated with dietary proteins, sulphur amino acids and calcium. CONCLUSIONS: The diet of the postmenopausal women studied were more compatible with national nutritional recommendations than that of premenopausal controls. However, these postmenopausal women, not taking hormone replacement therapy (HRT) and having inadequate dietary calcium and vitamin D intakes, may be at increased risk of osteoporotic fracture later in life. More studies on CVD risk inherent to body iron accumulation involving a large number of postmenopausal women are warranted before planning public health measures regarding dietary iron intake.     

Nutritional status and dietary intakes of children aged 2-5 years and their caregivers in a rural South African community

The objective of this study was to determine the nutritional status regarding vitamin A, iron and anthropometric indices and dietary intakes of children aged 2-5 years and their caregivers in a rural South African community. Micronutrient, haematological, anthropometric and dietary indicators were used to assess nutritional status during a cross-sectional survey. The setting was a low socioeconomic rural African community (Ndunakazi), approximately 60 km northwest of the coastal city of Durban in KwaZulu-Natal, South Africa. The subjects were children aged 2-5 years (n = 164), and their caregivers (n = 137). Of the preschool children, 50% had a low vitamin A status (serum retinol < 20 micrograms/dL), 54% were anaemic (Hb < 11 micrograms/dL), 33% had depleted iron stores (serum ferritin levels < 10 micrograms/L), and 21% were stunted (Z-score for height-for-age < -2SD). Of the caregivers, 30% had a low vitamin A status (serum retinol < 30 micrograms/dL), 44% were anaemic (Hb < 11 micrograms/dL), 19% had depleted iron stores (serum ferritin levels < 12 micrograms/L), and 40% and 26% were overweight (BMI > or = 24 and < 30) and obese (BMI > or = 30), respectively. The children and caregivers consumed a cereal-based diet, with phutu (a stiff porridge made with maize meal), rice and bread as staple foods. Quantitative dietary analysis showed that the dietary intakes were high in carbohydrates (approximately 70% of total energy), while fat intake was within the prudent dietary guideline of 30% of total energy intake. Median dietary intakes were below 50% of the RDA for calcium, zinc (children only), vitamin A, riboflavin, niacin (children only) and vitamin B12. These preschool children and their caregivers consumed a high carbohydrate diet deficient in most of the essential micronutrients. The poor quality of the diet was reflected in a poor vitamin A and iron status, and one-fifth of the children showed linear growth retardation. Nutrition education and intervention programmes should address micronutrient deficiencies, with the focus not only on quantity, but also quality of the diet.     

Nutrient intake and blood pressure: families of adult identical twins.

To investigate the relationship of dietary intake to blood pressure, 198 adults and 53 children who were members of 92 nuclear families completed a 3-day diet diary prior to an outpatient clinic examination for cardiovascular disease risk factors. Nutrient intake was significantly related to age and anthropometric variables in adults. Sodium and potassium intake were related to blood pressure in adults, but this relationship was no longer significant after adjustment for caloric intake. The diet and blood pressure relationships in children were less clear. Multiple linear regression techniques using age, anthropometric variables, and nutrient intake demonstrated that in adults age and skinfold were the principal determinants of blood pressure, but in children age and saturated fat intake were most likely to enter the equations. In comparisons of normotensive and hypertensive adults, there were no differences in the dietary intakes of these electrolytes. The results of this investigation underscore the complex interaction of nutrient intake with body size and age. Investigators who focus only on a few nutrients and fail to account for other sources of variation can be misled.     

Nutrient intake and blood pressure: families of adult identical twins

To investigate the relationship of dietary intake to blood pressure, 198 adults and 53 children who were members of 92 nuclear families completed a 3-day diet diary prior to an outpatient clinic examination for cardiovascular disease risk factors. Nutrient intake was significantly related to age and anthropometric variables in adults. Sodium and potassium intake were related to blood pressure in adults, but this relationship was no longer significant after adjustment for caloric intake. The diet and blood pressure relationships in children were less clear. Multiple linear regression techniques using age, anthropometric variables, and nutrient intake demonstrated that in adults age and skinfold were the principal determinants of blood pressure, but in children age and saturated fat intake were most likely to enter the equations. In comparisons of normotensive and hypertensive adults, there were no differences in the dietary intakes of these electrolytes. The results of this investigation underscore the complex interaction of nutrient intake with body size and age. Investigators who focus only on a few nutrients and fail to account for other sources of variation can be misled.     

Lead consumption of 18- to 36-month-old children as determined from duplicate diet collections: nutrient intakes,blood lead levels,and effects on growth

OBJECTIVE: To determine the amount of lead ingested in food by means of duplicate diet collections, nutrient intakes, and anthropometric measurements of young children. DESIGN: Once a month for a year, data were collected from 24-hour duplicate diets, hand wipes, a dust index, and anthropometric measurements. Quarterly, venous blood samples were obtained. Thermal ionization spectrometry by means of a lead-205 tracer was used to determine lead present in food, blood, and the hand wipes. A dust index was determined on the basis of observation of dust on surfaces in the home. Anthropometric measurements obtained were height, weight, head circumference, and mid-upper arm circumference. SUBJECTS/SETTING: Subjects were 21 children, aged 18 to 36 months, who resided in homes located in an urban area with potentially high lead levels. MAIN OUTCOMES MEASURED: Lead contamination in food and on hands, and blood lead values, were determined. STATISTICAL ANALYSIS PERFORMED: Pearson correlation coefficients were used to determine relationships between lead content in food, blood, and hand wipes and growth. Multiple regression analyses examined the effect of food types and dust lead on lead levels in food, and the effect of these variables on head circumference. RESULTS: Mean blood levels were 0.3089 +/- 0.1496 micromol/L; 12 samples contained more than 0.4826 micromol/L. Total intake of lead from food was 4.95 microg/day and ranged from 1.10 to -22.10 microg/day. More than a fourth of the diets collected exceeded 6.00 microg/day. Foods considered home prepared were moderately related to blood lead level, and the dust index and hand wipe lead levels were related to total food lead. Home-handled foods, canned foods, and hand-wipe lead were significant predictors of the lead content in food. A negative relationship was found between head circumference and blood lead level. APPLICATIONS: Level of lead in food was directly related to hand-wipe lead. This finding underscores the need for dietitians and other health professionals to stress the importance of cleanliness in environments that are potentially lead contaminated. Appropriate hand washing and surface cleaning should be emphasized when preparing and consuming food. The inverse relationship between head circumference and blood lead levels points to the need for additional studies to validate this finding while controlling for other extraneous variables.     

A Review of the Impact of Dietary Intakes in Human Pregnancy on Infant Birthweight

Studies assessing maternal dietary intakes and the relationship with birthweight are inconsistent, thus attempting to draw inferences on the role of maternal nutrition in determining the fetal growth trajectory is difficult. The aim of this review is to provide updated evidence from epidemiological and randomized controlled trials on the impact of dietary and supplemental intakes of omega-3 long-chain polyunsaturated fatty acids, zinc, folate, iron, calcium, and vitamin D, as well as dietary patterns, on infant birthweight. A comprehensive review of the literature was undertaken via the electronic databases Pubmed, Cochrane Library, and Medline. Included articles were those published in English, in scholarly journals, and which provided information about diet and nutrition during pregnancy and infant birthweight. There is insufficient evidence for omega-3 fatty acid supplements’ ability to reduce risk of low birthweight (LBW), and more robust evidence from studies supplementing with zinc, calcium, and/or vitamin D needs to be established. Iron supplementation appears to increase birthweight, particularly when there are increases in maternal hemoglobin concentrations in the third trimester. There is limited evidence supporting the use of folic acid supplements to reduce the risk for LBW; however, supplementation may increase birthweight by ~130 g. Consumption of whole foods such as fruit, vegetables, low-fat dairy, and lean meats throughout pregnancy appears beneficial for appropriate birthweight. Intervention studies with an understanding of optimal dietary patterns may provide promising results for both maternal and perinatal health. Outcomes from these studies will help determine what sort of dietary advice could be promoted to women during pregnancy in order to promote the best health for themselves and their baby.     

Diet in a group of 18-month-old children in South West England, and comparison with the results of a national survey

OBJECTIVE: To investigate the normal range of nutrient intakes and food consumption patterns in 18 month old children. SUBJECTS: 1,026 children resident in South West England, forming part of the Children in Focus (CIF) research cohort. METHODS: Diet was assessed using a 3 day unweighed dietary record. Nutrient and food intakes were compared with the dietary reference values and with the results of a British survey of preschool children -- the National Diet and Nutrition Survey (NDNS). RESULTS: Intakes of energy and nearly all nutrients were significantly higher in boys than in girls. Intakes of energy were slightly above the estimated average requirements. For most nutrients the mean and median intakes were well above the Reference Nutrient Intakes (RNI). The exceptions were vitamin D, iron and zinc. Nutrient intakes in CIF were very similar to those in the NDNS except for carotene, calcium, vitamin D and iodine, where intakes were considerably higher in CIF, and sugar intake which was lower in CIF. Intakes of most foods were similar in the two surveys. However, consumption of milk, yoghurt and fromage frais and baby foods was higher in CIF, intakes of most fruit and vegetables was somewhat higher, and intakes of savoury snacks and sugar confectionery were lower. In addition, there were differences between the two groups in the types of meat and meat products consumed. CONCLUSIONS: These children are unlikely to be deficient in any nutrients, with the possible exceptions of iron, zinc, and vitamin D. The use of vitamin D supplements and the inclusion of iron- and zinc-rich foods in the diets of preschool children should be encouraged. These data will be important in assessing the influence of early diet on subsequent health and development.     

Diet in a group of 18-month-old children in South West England, and comparison with the results of a national survey

Objective To investigate the normal range of nutrient intakes and food consumption patterns in 18-month-old children.
Subjects 1026 children resident in South West England, forming part of the Children in Focus (CIF) research cohort.
Methods Diet was assessed using a 3-day unweighed dietary record. Nutrient and food intakes were compared with the dietary reference values and with the results of a British survey of preschool children – the National Diet and Nutrition Survey (NDNS).
Results Intakes of energy and nearly all nutrients were significantly higher in boys than in girls. Intakes of energy were slightly above the estimated average requirements. For most nutrients the mean and median intakes were well above the Reference Nutrient Intakes (RNI). The exceptions were vitamin D, iron and zinc. Nutrient intakes in CIF were very similar to those in the NDNS except for carotene, calcium, vitamin D and iodine, where intakes were considerably higher in CIF, and sugar intake which was lower in CIF. Intakes of most foods were similar in the two surveys. However, consumption of milk, yoghurt and fromage frais and baby foods was higher in CIF, intakes of most fruit and vegetables was somewhat higher, and intakes of savoury snacks and sugar confectionery were lower. In addition, there were differences between the two groups in the types of meat and meat products consumed.
Conclusions These children are unlikely to be deficient in any nutrients, with the possible exceptions of iron, zinc and vitamin D. The use of vitamin D supplements and the inclusion of iron- and zinc-rich foods in the diets of preschool children should be encouraged. These data will be important in assessing the influence of early diet on subsequent health and development.     

云南大红山铜矿区成年居民铜、铁、锌血清水平和膳食摄入量

目的 了解云南大红山铜矿成年居民铜、铁、锌的血清水平和膳食摄入量.方法 在大红山矿区随机抽取180名成年居民,采用原子吸收分光光度法检测血清铜、铁、锌水平.从180人中随机抽取60人,采刚化学分析法调查膳食铜、铁、锌摄入量.结果 171人的血清铜、铁、锌水平分别为（0.90±0.18）、（1.25±0.93）、（0.75±0.28）mg/L,血清铜和铁呈显著负相关（r=-0.26,P＜0.001）.血清铜与年龄呈显著正相关（r=0.25,P＜0.001）,女性血清铜水平明显高于男性（P=0.011）.60人的膳食铜、铁、锌摄入量分别为（1.74±1.09）、（16.29±10.73）、（7.56±3.38）mg/d,女性均明显低于男性（P＜0.05）.血清铜、铁、锌水平和膳食摄入量均存在地区差异.结论 云南大红山矿区成年居民血清铜、铁水平均正常,血清锌水平偏低.铜、铁、锌的膳食摄入量均未超过可耐受最高摄人量,且部分人摄入量偏低.     

Nutritional status and dietary intakes of children aged 2–5 years and their caregivers in a rural South African community

The objective of this study was to determine the nutritional status regarding vitamin A, iron and anthropometric indices and dietary intakes of children aged 2-5 years and their caregivers in a rural South African community. Micronutrient, haematological, anthropometric and dietary indicators were used to assess nutritional status during a cross-sectional survey. The setting was a low socioeconomic rural African community (Ndunakazi), approximately 60 km northwest of the coastal city of Durban in KwaZulu-Natal, South Africa. The subjects were children aged 2-5 years (n = 164), and their caregivers (n = 137). Of the preschool children, 50% had a low vitamin A status (serum retinol < 20 μ g/dL), 54% were anaemic (Hb < 11 μ g/dL), 33% had depleted iron stores (serum ferritin levels < 10 μ g/L), and 21% were stunted (Z-score for height-for-age < -2SD). Of the caregivers, 30% had a low vitamin A status (serum retinol < 30 μ g/dL), 44% were anaemic (Hb < 11 μ g/dL), 19% had depleted iron stores (serum ferritin levels <12 μ g/L), and 40% and 26% were overweight (BMI ≥ 24 and <30) and obese (BMI ≥ 30), respectively. The children and caregivers consumed a cereal-based diet, with phutu (a stiff porridge made with maize meal), rice and bread as staple foods. Quantitative dietary analysis showed that the dietary intakes were high in carbohydrates (~70% of total energy), while fat intake was within the prudent dietary guideline of 30% of total energy intake. Median dietary intakes were below 50% of the RDA for calcium, zinc (children only), vitamin A, riboflavin, niacin (children only) and vitamin B 12. These preschool children and their caregivers consumed a high carbohydrate diet deficient in most of the essential micronutrients. The poor quality of the diet was reflected in a poor vitamin A and iron status, and one-fifth of the children showed linear growth retardation. Nutrition education and intervention programmes should address micronutrient deficiencies, with the focus not only on quantity, but also quality of the diet.     

Supplement use: is there any nutritional benefit?

OBJECTIVE: To examine the role of dietary supplements in improving total nutrient intakes in adults. DESIGN: Dietitian-administered 24-hour recalls (of intake including supplements) were conducted in 1997 and 1998. Supplement users were categorized into groups based on the types of supplements used and nutrient intake was examined. SUBJECTS: Using a multistage, stratified random sampling, 1,530 Canadian adults aged 19 to 65 years were surveyed. STATISTICAL ANALYSES PERFORMED: Intakes from diet, supplements, and diet plus supplements were examined by age/gender stratification. RESULTS: Supplement users had dietary intakes, from food alone, similar to nonusers with mean intakes in some age/sex groups below the Recommended Daily Allowance (RDA)/Adequate Intake (AI) for iron, calcium, and folate. Multivitamin users had mean intakes (from diet plus supplement) of folate above the RDA and iron intakes also increased to RDA levels among women aged 19 to 50 years. Calcium supplement users had lower calcium and vitamin D intakes than nonusers from diet alone in some age/sex groups. Calcium tablets increased mean calcium intakes to AI levels among all age/sex groups. Many supplement users exceeded the new Upper Limits of safe intake; 47% in the case of niacin. APPLICATIONS: Supplements are commonly used and can help some persons adhere to Dietary Reference Intake recommendations concerning intake of folate, calcium, vitamin D. and iron. We found multivitamin users to have higher total intakes of folic acid, iron, calcium, and vitamin D. Also, targeted use of calcium supplements effectively enhanced intakes. However, concurrent vitamin D supplementation is important and awareness of product composition with respect to Upper Limits is essential.     

Gestational hyperglycemia, zinc, selenium, and antioxidant vitamins

OBJECTIVE: Lower levels of selenium and vitamin E have been described in gestational diabetes, a condition similar to type 2 diabetes, but few data are available about zinc (known to be associated with diabetes) and gestational hyperglycemia. This study evaluated the dietary intake of antioxidant vitamins, zinc, selenium, and serum levels of zinc and selenium in women with gestational hyperglycemia and normoglycemia. METHODS: A food-frequency questionnaire was administered to 504 pregnant women (210 with hyperglycemia and 294 with normoglycemia). Serum levels of zinc and selenium were analyzed during pregnancy in a second cohort of 71 hyperglycemic and 123 normoglycemic women, with a mean age and body mass index similar to those in the first cohort. RESULTS: Dietary intakes of zinc and selenium were significantly lower in hyperglycemic patients. In multiple logistic regression analysis, intakes were negatively associated with gestational hyperglycemia (odds ratios of 0.89 for zinc and 0.97 for selenium) after multiple adjustments. There were no significant differences in vitamin intakes. In the second cohort of 194 patients, serum levels of zinc and selenium were significantly lower in patients who had impaired glucose tolerance and negatively associated with gestational hyperglycemia in a multiple logistic regression model (odds ratios of 0.93 for serum zinc and 0.92 for serum selenium). CONCLUSIONS: Our data suggested a significant inverse association of dietary intakes and serum levels of zinc and selenium with gestational hyperglycemia. If future studies confirm these results, it might be a useful interventional approach to appropriate dietary counseling in order to evaluate the possible decrease in gestational metabolic abnormalities and their adverse consequences.     

哺乳期农村乳母乳汁无机元素含量的变化

目的了解哺乳期人乳无机元素含量的变化及其与乳母膳食的关联。方法采用横断面调查方法,收集55名陕西省澄城县农村健康乳母清晨乳样,利用原子吸收分光光度法测定乳汁钙、镁、铁、锰、锌和铜的浓度。采用24小时回顾法进行连续3天膳食调查,计算膳食营养素的摄入量。结果农村乳母乳汁中镁、锌、铜浓度随哺乳期延长明显降低,铁浓度随哺乳期延长而上升。乳母膳食钙摄入量约为钙膳食参考摄入量(DRI)1/3,膳食无机元素的摄入量与人乳相应元素之间无明显相关性。多因素分析表明,乳汁中钙与镁、铁与铜、锰与锌均呈正相关,钙分别与乳脂、铁、锌呈负相关。结论随哺乳期时间延长,成熟乳中镁、锌、铜浓度降低而铁浓度增加,乳母膳食钙的摄入严重不足,乳汁各元素与膳食相应元素之间无关联。     

Zinc-vitamin A interaction in pregnant and fetal rats: supplemental vitamin A does not prevent zinc-deficiency-induced teratogenesis

The influence of a higher-than-normal intake of vitamin A on the detrimental effects of zinc deficiency on vitamin A metabolism was investigated in pregnant Sprague-Dawley rats. At mating, rats were fed diets containing 100 (control), 4.5, or 0.5 micrograms/g zinc combined with 4 (control) or 8 micrograms retinyl acetate/g. Low intake of zinc, but not of vitamin A, caused food intake, total body weight change, fetal weight and placental weight to be low. Incidence of teratogenic effects was more pronounced in low zinc groups than in controls. Concentrations of vitamin A in maternal plasma and liver were affected by the amount of zinc in the diet. Dietary vitamin A, however, did not affect either of these parameters. Maternal plasma zinc concentration was affected only by low dietary zinc, whereas plasma copper and iron were unaffected by the dietary treatments. Maternal liver iron was higher in zinc-deficient rats than in controls; however, maternal liver zinc and copper concentrations were not altered by dietary treatments. No significant differences in vitamin A concentration of fetal liver, fetal plasma, or placenta were seen among the groups. Fetuses from zinc-deficient dams had significantly lower levels of liver vitamin A and liver zinc than did controls. Fetal liver iron was higher in zinc-deficient fetuses than in controls, whereas fetal liver copper was not affected by dietary treatment. These data suggest that supplemental dietary vitamin A does not ameliorate the effect of zinc deficiency on vitamin A metabolism during pregnancy.