Retinol, carotenoids, and tocopherols in the milk of lactating adolescents and relationships with plasma concentrations

OBJECTIVE: We determined the concentrations of retinol, carotenoids, and tocopherols in breast milk of adolescents and evaluated their associations with plasma levels and with maternal characteristics (period of lactation, body mass index, age of menarche, and years postmenarche). METHODS: This was a single cross-sectional survey of retinol, carotenoid, and tocopherol composition of milk and plasma of lactating adolescent mothers (n = 72; 30-120 d postpartum) attending public daycare clinics in Rio de Janeiro, Brazil. Milk and plasma components were analyzed by high-performance liquid chromatography. RESULTS: Nutrient concentrations (micromoles per liter, mean +/- SE) in plasma and milk were, respectively, retinol 2.1 +/- 0.5 and 0.62 +/- 0.44, beta-carotene 0.18 +/- 0.19 and 0.016 +/- 0.017, alpha-carotene 0.05 +/- 0.04 and 0.0035 +/- 0.002, lutein plus zeaxanthin 0.15 +/- 0.11 and 0.025 +/- 0.024, lycopene 0.1 +/- 0.11 and 0.016 +/- 0.025, alpha-tocopherol 10.8 +/- 5.3 and 2.7 +/- 1.8, gamma-tocopherol 2.6 +/- 2.3 and 0.37 +/- 0.15. The milk/plasma molar ratios of retinol and tocopherols were two times higher than those of carotenoids. Significant correlations (P < 0.001) between milk and plasma nutrient levels were observed for beta-carotene (r = 0.41), alpha-carotene (r = 0.60), and lutein plus zeaxanthin (r = 0.57), but not for lycopene, retinol, and tocopherols. Nutrient concentrations in plasma and in milk were not associated with the maternal characteristics investigated. CONCLUSION: Concentrations of the nutrients studied, especially retinol and alpha-tocopherol, in mature milk of lactating adolescents were, in general, lower than in milk of adult lactating women. Milk concentrations were associated with plasma concentrations only for beta-carotene, alpha-carotene, and lutein plus zeaxanthin.     

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。     

Maternal zinc supplementation and growth in Peruvian infants

BACKGROUND: Little is known about how maternal zinc intake influences growth in utero and in postnatal life in humans. OBJECTIVE: We aimed to assess the effect of maternal zinc supplementation during pregnancy on infant growth through age 1 y. DESIGN: A double-blind, randomized controlled trial of prenatal zinc supplementation was conducted from 1995 to 1997 in Lima, Peru. Women (n = 1295) were enrolled at 15.6 +/- 4.6 wk gestation and assigned to receive daily supplements with zinc (15 mg Zn + 60 mg Fe + 250 microg folic acid) or without zinc (60 Fe + 250 microg folic acid) through pregnancy to 1 mo after delivery. At birth, 546 infants were followed for 12 mo to assess growth. Anthropometric measures of body size and composition were collected monthly, and morbidity and dietary intake surveillance was carried out weekly. RESULTS: No differences in maternal socioeconomic characteristics by treatment group or follow-up period were found. Infants born to mothers prenatally supplemented with zinc had significantly (P < 0.05) larger average growth measures beginning in month 4 and continuing through month 12. In longitudinal regression modeling, prenatal zinc was associated with greater weight (by 0.58 +/- 0.12 kg; P < 0.001), calf circumference (by 1.01 +/- 0.21 cm; P < 0.001), chest circumference (by 0.60 +/- 0.20 cm; P = 0.002), and calf muscle area (by 35.78 +/- 14.75 mm(2); P = 0.01) after adjustment for a range of covariates. No effect was observed for linear growth. CONCLUSION: Maternal zinc supplementation in this population was associated with offspring growth, which is suggestive of lean tissue mass accretion.     

Adding zinc to prenatal iron and folate supplements improves maternal and neonatal zinc status in a Peruvian population.

BACKGROUND: Maternal zinc deficiency during pregnancy may be widespread among women in developing countries, but few data are available on whether prenatal zinc supplementation improves maternal and neonatal zinc status. OBJECTIVE: We studied whether maternal zinc supplementation improved the zinc status of mothers and neonates participating in a supplementation trial in a shantytown in Lima, Peru. DESIGN: Beginning at gestation week 10-24, 1295 mothers were randomly assigned to receive prenatal supplements containing 60 mg Fe and 250 microg folate, with or without 15 mg Zn. Venous blood and urine samples were collected at enrollment, at gestation week 28-30, and at gestation week 37-38. At birth, a sample of cord vein blood was collected. We measured serum zinc concentrations in 538 women, urinary zinc concentrations in 521 women, and cord zinc concentrations in 252 neonates. RESULTS: At 28-30 and 37-38 wk, mothers receiving zinc supplements had higher serum zinc concentrations than mothers who did not receive zinc (8.8 +/- 1.9 compared with 8.4 +/- 1.5 micromol/L and 8.6 +/- 1.5 compared with 8.3 +/- 1.4 micromol/L, respectively). Urinary zinc concentrations were also higher in mothers who received supplemental zinc (P < 0.05). After adjustment for covariates and confounding factors, neonates of mothers receiving zinc supplements had higher cord zinc concentrations than neonates of mothers who did not receive zinc (12.7 +/- 2.3 compared with 12.1 +/- 2.1 micromol/L). Despite supplementation, maternal and neonatal zinc concentrations remained lower than values reported for well-nourished populations. CONCLUSION: Adding zinc to prenatal iron and folate tablets improved maternal and neonatal zinc status, but higher doses of zinc are likely needed to further improve maternal and neonatal zinc status in this population.     

trans Fatty acids in human milk are inversely associated with concentrations of essential all-cis n-6 and n-3 fatty acids and determine trans, but not n-6 and n-3, fatty acids in plasma lipids of breast-fed infants.

BACKGROUND: Human milk fatty acids vary with maternal dietary fat composition. Hydrogenated dietary oils with trans fatty acids may displace cis n-6 and n-3 unsaturated fatty acids or have adverse effects on their metabolism. The effects of milk trans, n-6, and n-3 fatty acids in breast-fed infants are unclear, although n-6 and n-3 fatty acids are important in infant growth and development. OBJECTIVE: We sought to determine the relations between trans and cis unsaturated fatty acids in milk and plasma phospholipids and triacylglycerols of breast-fed infants, and to identify the major maternal dietary sources of trans fatty acids. DESIGN: We collected milk from 103 mothers with exclusively breast-fed 2-mo-old infants, blood from 62 infants, and 3-d dietary records from 21 mothers. RESULTS: Mean (+/-SEM) percentages of trans fatty acids were as follows: milk, 7.1 +/- 0.32%; infants' triacylglycerols, 6.5 +/- 0. 33%; and infants' phospholipids, 3.7 +/- 0.16%. Milk trans fatty acids, alpha-linolenic acid (18:3n-3), arachidonic acid (20:4n-6), docosahexaenoic acid (22:6n-3) (P < 0.001), and linoleic acid (18:2n-6) (P = 0.007) were each related to the same fatty acid in infant plasma phospholipids. Milk trans fatty acids were inversely related to milk 18:2n-6 and 18:3n-3, but not to milk or infant plasma 20:4n-6 or 22:6n-3. trans Fatty acids represented 7.7% of maternal total fat intake (2.5% of total energy); the major dietary sources were bakery products and breads (32%), snacks (14%), fast foods (11%), and margarines and shortenings (11%). CONCLUSIONS: There were comparable concentrations of trans fatty acids in the maternal diet, breast milk, and plasma triacylglycerols of breast-fed infants. Prepared foods were the major dietary source of trans fatty acids.     

Trace element nutrition status and dietary intake of children with phenylketonuria

The trace element status (copper, iron, zinc, manganese, chromium, and selenium) of 20 dietetically treated phenylketonuric (PKU) children was assessed. Significantly higher intakes of copper (p = 0.002) and iron (p = 0.005) were noted in PKU children compared with their siblings. No significant differences were found for zinc, manganese, or chromium. Intake of selenium was significantly lower (p = 0.0001) in PKU children (8.4 +/- 3.9 micrograms/d) than in siblings (41.6 +/- 9.4 micrograms/d). Plasma and urine selenium and erythrocyte glutathione peroxidase activity (GSHpx) were significantly lower (p = 0.001) in PKU children (0.38 +/- 0.11 mumol/L, 58.0 +/- 34.5 nmol/d, and 14.2 +/- 5.5 U/g Hb, respectively) than in siblings (0.82 +/- 0.15 mumol/L, 165.2 +/- 49.4 nmol/d, and 22.7 +/- 5.2 U/g Hb, respectively). No differences were found in plasma and urine concentrations of other elements. Intake of selenium was significantly correlated with erythrocyte GSHpx (r = 0.87, p = 0.0001) and plasma selenium (r = 0.71, p = 0.0001) for the combined groups. The need and possible procedures, including dietary manipulation, for increasing selenium intake in PKU subjects are discussed.     

Plasma zinc and copper concentrations in rheumatoid arthritis: influence of dietary factors and disease activity

Forty patients with rheumatoid arthritis performed a thorough 7-d diet recording. The food diaries were analyzed together with clinical and laboratory data by means of stepwise multiple linear regression to clarify the effects of both diet and the inflammatory disorder on the plasma concentrations of zinc and copper. The patients' daily dietary intakes of zinc and copper (24.3 +/- 7.54 and 3.48 +/- 1.55 mg/MJ) were comparable to the corresponding intakes in the ordinary Finnish diet (24.0 and 3.68 mg/MJ). In multivariate analyses the best predictors of plasma trace elements were the measures of disease activity and not the dietary factors. As an exception to this, there was a strong correlation between plasma copper-copper intake ratio and zinc intake both in univariate (r = -0.638, P less than 0.001) and multivariate analysis. This suggests that zinc depresses copper absorption with intakes in normal, physiological ranges.     

Prenatal iron supplements impair zinc absorption in pregnant Peruvian women

Prenatal iron supplements may adversely influence zinc absorption during pregnancy. To examine the impact of prenatal iron supplements on supplemental zinc absorption, fractional zinc absorption was measured in 47 pregnant Peruvian women during the third trimester of pregnancy (33 +/- 1 wk gestation). Of these 47 women, 30 received daily prenatal supplements from wk 10-24 of pregnancy until delivery. Supplements contained 60 mg of Fe and 250 microg of folate without [iron group (Fe), n = 16] or with [iron and zinc supplemented group (Fe + Zn), n = 14] 15 mg of Zn. The remaining 17 women [unsupplemented control group (C)] received no prenatal supplementation. Zinc concentrations were measured in plasma, urine and cord blood and percentage zinc absorption was determined following dosing with oral ((67)Zn) and intravenous ((70)Zn) stable zinc isotopes. Percentage zinc absorption was significantly lower than controls in fasting women receiving iron- containing prenatal supplements (20.5 +/- 6.4 vs. 20.2 +/- 4.6 vs. 47.0 +/- 12.6%, Fe, Fe + Zn and C groups, respectively, P: < 0.0001, n = 40). Plasma zinc concentrations were also significantly lower in the Fe group compared to the C group (8.2 +/- 2.2 vs. 9.2 +/- 2.2 vs. 10.9 +/- 1. 8 micromol/L, Fe, Fe + Zn and C groups, respectively, P: = 0.002), and cord zinc concentrations were significantly related to maternal plasma Zn levels (y = 6.383 + 0.555x, r = 0.486, P: = 0.002). The inclusion of zinc in prenatal supplements may reduce the potential for iron supplements to adversely influence zinc status in populations at risk for deficiency of both these nutrients.     

Calcium supplementation and plasma ferritin concentrations in premenopausal women.

The effect of calcium supplement use on iron stores was examined in a randomized controlled study in free-living, healthy, premenopausal women. Of 109 women who completed the study, 52 were in the control group and 57 took two tablets containing 250 mg Ca as the carbonate with each of two meals daily for 12 wk. In all subjects at baseline, plasma ferritin concentrations were positively correlated with heme-iron intake (r = 0.21, P = 0.04), serum iron concentration (r = 0.19, P = 0.04), transferrin saturation (r = 0.31, P = 0.001), and hemoglobin concentration (r = 0.22, P = 0.02), and negatively correlated with total iron-binding capacity (TIBC, r = -0.42, P < 0.001). No significant differences in absolute or percent changes in plasma ferritin concentrations, serum iron concentrations, TIBC, transferrin saturation, hemoglobin concentrations, or hematocrit were observed between the treatment and control groups. Thus, over a 12-wk period, use of 1000 mg Ca as the carbonate daily with meals does not appear to be detrimental to iron stores in healthy, free-living, premenopausal women.     

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.     

Zinc plus beta-carotene supplementation of pregnant women is superior to beta-carotene supplementation alone in improving vitamin A status in both mothers and infants

BACKGROUND: Deficiencies of vitamin A, iron, and zinc are prevalent in women and infants in developing countries. Supplementation during pregnancy can benefit mother and infant. OBJECTIVE: We examined whether supplementation during pregnancy with iron and folic acid plus beta-carotene or zinc or both improves the micronutrient status of mothers and infants postpartum. DESIGN: Pregnant women (n = 170) were supplemented daily only during pregnancy with beta-carotene (4.5 mg), zinc (30 mg), or both or placebo plus iron (30 mg) and folic acid (0.4 mg) in a randomized, double-blind, placebo-controlled trial. Micronutrient status was assessed 1 and 6 mo postpartum. RESULTS: Six months postpartum, plasma retinol concentrations were higher in the women who received zinc during pregnancy than in women who did not. Infants born to mothers supplemented with beta-carotene + zinc had higher plasma retinol concentrations, with the frequency of vitamin A deficiency reduced by >30% compared with the other 3 groups. Breast-milk beta-carotene concentrations were higher in all women supplemented with beta-carotene, but breast-milk retinol concentrations were higher only in women who received beta-carotene + zinc. Zinc concentrations did not differ among groups in mothers and infants. CONCLUSIONS: Zinc supplementation during pregnancy improved the vitamin A status of mothers and infants postpartum, which indicates a specific role of zinc in vitamin A metabolism. Addition of both beta-carotene and zinc to iron supplements during pregnancy could be effective in improving the vitamin A status of mothers and infants.     

不同地区乳汁中锌、铜、铁含量的研究

本研究收集了我国７个不同地区共１０１２份产后１～６个月乳母的乳汁进行了锌、铜、铁含量测定，结果均以产后１２天较高，其平均含量分别为４．５２±１．７０，０．５１±０．１６和１．０３±０．５３μｇ／ｇ，并随泌乳期延长而下降。不同地区乳汁中锌、铜、铁含量存在一定差异。各地区乳汁中锌含量均与乳母膳食中动物性来源锌及动物性蛋白质摄取量呈正相关。乳汁中铜含量与乳母膳食中动物性蛋白质摄取量也呈正相关。未发现乳汁中铁含量与乳母膳食中营养素的摄取量有关。     

Dietary selenium intake and selenium concentrations of plasma, erythrocytes, and breast milk in pregnant and postpartum lactating and nonlactating women

The selenium status of a group of 23 lactating and 13 nonlactating women was assessed from 37-wk gestation through 6-mo postpartum. The mean overall dietary Se intake of both groups of women was 80 +/- 37 micrograms/d. Plasma and erythrocyte Se levels were lower in the lactating than in the nonlactating mothers both before and after parturition. Breast-milk Se concentrations fell from 20 micrograms/L (0.25 mumol/L) at 1-mo postpartum to 15 micrograms/L (0.19 mumol/L) at 3- and 6-mo postpartum. A weak (r = 0.38) but statistically significant (p less than 0.025) relationship was observed between maternal plasma Se level and breast-milk Se concentration. The dietary Se intake of these lactating North American women appears sufficient to maintain satisfactory Se nutriture in their breast-fed infants during the first 6 mo of lactation.     

Influence of prenatal iron and zinc supplements on supplemental iron absorption, red blood cell iron incorporation, and iron status in pregnant Peruvian women

BACKGROUND: It is estimated that 60% of pregnant women worldwide are anemic. OBJECTIVE: We aimed to examine the influence of iron status on iron absorption during pregnancy by measuring supplemental iron absorption, red blood cell iron incorporation, and iron status in pregnant women. DESIGN: Subjects were 45 pregnant Peruvian women (33+/-1 wk gestation), of whom 28 received daily prenatal supplements containing 60 mg Fe and 250 microg folate without (Fe group, n = 14) or with (Fe+Zn group, n = 14) 15 mg Zn, which were were consumed from week 10 to 24 of gestation until delivery. The remaining 17 women (control) received no prenatal supplementation. Iron status indicators and isotopes were measured in maternal blood collected 2 wk postdosing with oral (57Fe) and intravenous (58Fe) stable iron isotopes. RESULTS: Maternal serum ferritin and folate concentrations were significantly influenced by supplementation (P < 0.05). Serum iron was also significantly higher in the Fe than in the Fe+Zn (P < 0.03) or control (P < 0.001) groups. However, the supplemented groups had significantly lower serum zinc concentrations than the control group (8.4+/-2.3 and 10.9+/-1.8 micromol/L, respectively, P < 0.01). Although percentage iron absorption was inversely related to maternal serum ferritin concentrations (P = 0.036), this effect was limited and percentage iron absorption did not differ significantly between groups. CONCLUSIONS: Because absorption of nonheme iron was not substantially greater in pregnant women with depleted iron reserves, prenatal iron supplementation is important for meeting iron requirements during pregnancy.     

Population-based study of alpha- and gamma-tocopherol in plasma and adipose tissue as biomarkers of intake in Costa Rican adults

BACKGROUND: gamma-Tocopherol is the most abundant form of vitamin E in the US diet, but alpha-tocopherol concentrations are the highest in plasma and tissues. Although plasma and adipose tissue concentrations of alpha-tocopherol have been used as biomarkers of intake, the relation between gamma-tocopherol intake and concentrations in plasma and adipose tissue is unknown. OBJECTIVE: Our goal was to investigate in a randomly selected population from Costa Rica whether plasma or adipose tissue concentrations of alpha- and gamma-tocopherol are suitable biomarkers of intake. DESIGN: A total of 361 men (x +/- SD age: 55 +/- 11 y) and 121 women (aged 59 +/- 10 y) completed a 135-item food-frequency questionnaire and provided a fasting blood sample and adipose tissue biopsy sample. RESULTS: Dietary gamma-tocopherol correlated with adipose tissue (r = 0.37, P < 0.001) and plasma (r = 0.42, P < 0.001) concentrations, regardless of supplement use. Dietary alpha-tocopherol correlated poorly with adipose tissue (r = 0.15, P < 0.01) and plasma (r = 0.16, P < 0.001) concentrations, and these correlations were even lower when users of vitamin supplements (n = 24) were excluded (adipose tissue: r = 0.10, P < 0.05; plasma: r = 0.09, P < 0.05). Compared with subjects who reported palm shortening (36%) as the major type of fat used for cooking, subjects using soybean oil (52%) had higher amounts of both alpha- and gamma-tocopherol in their diets. However, only gamma-tocopherol concentrations were higher in the plasma and adipose tissue of soybean oil users. CONCLUSIONS: Plasma and adipose tissue concentrations of gamma-tocopherol are equally good biomarkers of intake. The weak associations between alpha-tocopherol intake and plasma or adipose tissue concentrations suggest that these biomarkers are influenced more by factors other than alpha-tocopherol intake.     

Maternal smoking is associated with decreased 5-methyltetrahydrofolate in cord plasma

BACKGROUND: Maternal-fetal folate transport via the placenta has been shown to be concentrative. Exposure to cigarette smoke is associated with decreased maternal folate status through altered dietary intakes and possibly through nondietary mechanisms such as increased folate turnover. The effect of maternal smoking on fetal folate status has not been documented. OBJECTIVE: The objective was to determine the effect of maternal smoking on plasma 5-methyltetrahydrofolic acid (5-MTHFA) concentrations in umbilical cord blood. DESIGN: African American women were recruited from an antenatal clinic in Detroit, MI. Plasma 5-MTHFA concentrations were measured in maternal-umbilical cord pairings (n = 58). The participants completed a structured interview to determine demographic characteristics, including smoking. RESULTS: Concentrations of 5-MTHFA were significantly higher in venous cord plasma (16.8 +/- 7.5 ng/mL) than in maternal plasma (13.0 +/- 7.5 ng/mL) but remained associated (r = 0.60, P < 0.001) with each other. Cigarettes smoked by the mothers was negatively associated (r = -0.31, P = 0.019) with venous cord 5-MTHFA concentrations and remained so after control for maternal plasma 5-MTHFA and other variables. Venous cord plasma 5-MTHFA was significantly lower in smoking (15.1 +/- 7.6 ng/mL; n = 32) than in nonsmoking (19.0 +/- 7.0 ng/mL; n = 26) mothers. CONCLUSIONS: Cord plasma 5-MTHFA concentrations were elevated relative to maternal blood, as expected, because the placenta is capable of concentrative folate transport to the fetus. The negative effect of maternal smoking on infant, but not on maternal, 5-MTHFA status indicates that maternal smoking may impair folate transport to the fetus.     

Maternal sociodemographic parameters: impact on trace element status and pregnancy outcomes in Nigerian women

To determine the impact of socioeconomic status on plasma trace element status and pregnancy outcomes, 349 pregnant women, aged 15-40 years (mean 27.04 +/- 2.75 years), recruited at < or = 25 weeks (mean 21.76 +/- 3.12 weeks) gestational age, were followed up till delivery during which maternal and foetal outcomes were recorded. Plasma copper, iron, and zinc were determined using atomic absorption spectrophotometer while maternal sociodemographic data were obtained using a questionnaire. Except for copper, lower plasma iron and zinc were significantly (p < 0.05) higher in women from socioeconomically-disadvantaged groups. Both adverse maternal health and foetal outcomes also seemed to be more prevalent in socioeconomically-disadvantaged women, although without a definite trend. This study has shown that, in economically-disadvantaged setting of developing countries, maternal socioeconomic status impacts on maternal trace element (copper, iron, and zinc) status and health and foetal outcomes.     

Zinc and iron nutrition in Chilean children fed fortified milk provided by the Complementary National Food Program

OBJECTIVE: Chilean infants are at risk for isolated zinc and iron deficiencies because of a low consumption of animal products in low socioeconomic sectors. In 1999, the National Complementary Food Program of Chile manufactured a new milk (2 kg of powdered milk/mo) fortified with iron (Fe; 10 mg/L), zinc (Zn; 5 mg/L), and copper (0.5 mg/L) to be provided to infants until age 18 mo and to pregnant women. We analyzed the nutrition status of zinc and iron at age 18 mo in infants who consumed the fortified cow's milk. METHODS: Forty-two healthy male children with normal growth and from lower socioeconomic groups were studied. A nutrition survey was conducted; blood and hair samples for Zn in plasma and hair, hemoglobin, hematocrit, and serum ferritin were obtained. RESULTS: Mean intakes were: energy, 106 +/- 27 kcal. kg(-1). d(-1); protein, 3.8 +/- 1.1 g. kg(-1). d(-1); Zn, 5.2 +/- 1.9 g/d (0.98 mg Zn/MJ; 68% of World Health Organization recommendations); Fe, 11.2 +/- 5.5 mg/d; and dietary fiber, 9.8 +/- 3.9 g/d. Plasma Zn in 54.8% of children was no greater than 12.3 microM/L; 36% had hair Zn level no greater than 1.23 microM/g and 39% had serum ferritin levels no greater than 10 microg/dL (12% were anemic). Hair Zn was correlated to socioeconomic level (Spearman's rank correlation, r = -0.53; P < 0.001) and plasma Zn was correlated to the z weight/length (r = 0.47; P < 0.05), subscapular skinfold (r = 0.46; P < 0.05), and Zn intake (r = 0.46; P < 0.05). CONCLUSIONS: The fortified powdered cow's milk provided to infants until age 18 mo by the Complementary Food Program in Chile favorably affects the Fe status of these children, but possibly not the Zn nutrition; we suggest re-evaluation of the levels of Zn fortification.     

Nutritional status of adolescent girls in regard to zinc, copper, and iron

Adolescent girls in the sixth through eight grades were surveyed for dietary intake and nutritional status in regard to zinc, copper, and iron in both the fall of 1975 and the spring of 1976. The adolescents (183 girls in the fall and 184 girls in the spring) consumed on the average 60 and 75% of the Recommended Dietary Allowances for iron and zinc, respectively. The mean concentration of zinc in hair samples was 216 +/- 64 microgram/g in the fall and 191 +/- 36 microgram/g in the spring. The mean concentration of copper in hair samples was 31 +/- 23 microgram/g. None of the girls had a concentration of zinc in their hair samples of less than 100 microgram/g. Hair concentrations of zinc anc copper were significantly correlated, but serum and hair concentrations of zinc were inversely correlated. However, in subsample of 102 girls, 3% has serum zinc levels below 70 microgram/100 ml and 4% had serum copper levels below 70 microgram/100 ml. Only 1% of the subjects had a hematocrit below 36%. No significant difference in any of these parameters was noted between girls who had experienced menarche and those who had not.     

Investigation of Iron and Zinc Concentrations in Human Milk in Correlation to Maternal Factors: An Observational Pilot Study in Poland

The aim of this study was to evaluate iron and zinc concentrations in the mature human milk (HM) and to investigate the relationship between these concentrations and maternal factors. HM samples were collected between 4–6 weeks postpartum from 32 healthy, exclusively breastfeeding mothers. The assessment of dietary intake during breastfeeding was based on a food frequency questionnaire and three-day dietary records. Nutritional status of participants was assessed with body mass index and body composition analysis, measured with bioelectrical impedance. HM intake was assessed with infants’ weighting, whereas iron and zinc contents in HM were determined by inductively coupled plasma mass spectrometer. The median intake of HM was 492.5 mL (466–528.5) and the concentrations of HM iron and zinc were 0.33 mg/L (0.26–0.46) and 2.12 mg/L (1.97–2.45), respectively. Maternal total zinc and iron intake (diet + supplementation) was positively correlated with their concentrations in HM. Consumption frequency of meat, vegetables and legumes was revealed to be a significant factor influencing zinc concentration in HM. Regarding iron, it was the consumption frequency of meat, fish and seafood, vegetables and legumes, nuts and seeds. The intake of iron from HM was low, and after assuming a mean fractional iron absorption, it was only 0.038 mg/d. Our results show that maternal diet influences iron and zinc content in HM, suggesting that adequate intake of food rich in investigated minerals may be a positive factor for their concentrations in HM.