Daily dietary intake of copper,zinc, and selenium of exclusively breast-fed infants of middle-class women in Burundi,Africa

Copper (Cu), zinc (Zn), and selenium (Se) in human milk of middle-class Burundian women during the first 10 mo of lactation have been determined. Wet acid digestion, using nitric and perchloric acids, and atomic absorption spectrometric analysis have been used. Daily intakes have been calculated and proven to decrease from 0.39±0.05 (colostrum) to 0.16±0.02 (mature milk), 2.3±0.3 (colostrum), to 1.2±0.2 mg (mature milk) and 10.9±1.5 (colostrum) to 5.3±0.8 μg (mature milk) for Cu, Zn, and Se, respectively. Since values for this African country are nonexistent, intake levels are compared with literature data and found to be somewhat higher than those observed in other poorly nourished countries. The recommended safe and adequate daily intake for infants of 0–6 mo of age, as proposed by the National Research Council of the USA, is only met for Burundian infants <1 mo of age. The function of copper (Cu) and zinc (Zn) as essential trace elements has been known for quite a number of years (1). Also, selenium (Se) is a trace element essential for the activity of glutathione peroxidase (2) and type I iodothyronine 5-deiodinase (3). For all three elements, an adequate intake is necessary for satisfactory infant growth and development (4). In view of the almost total lack of relevant data on Burundi (Africa), we have determined Cu, Zn, and Se in human milk of middle-class Burundian women during the first 10 mo of lactation (5). The aim of this study is to assess infants' elemental intake for this country and compare this with literature data on trace elemental intake of exclusively breast-fed infants.     

Longitudinal body composition data in exclusively breast-fed infants: a multicenter study

Reference %fat and total fat-free mass data is necessary for evaluating growth in infants. We aimed to develop longitudinal %fat and total fat-free mass data in infants from birth to 6 months of age. An observational, multicenter, prospective cohort study was conducted with assessments at birth, 1 week, 2 weeks, 1, 2, 3, 4, 5, and 6 months of age. Subjects were exclusively breast-fed and were enrolled at three centers. Whole-body composition (i.e., % fat and total fat-free mass) were assessed using air-displacement plethysmography (ADP) (PEA POD; Life Measurement, Concord, CA). Maternal prepregnancy BMI, gestational weight gain, and infant anthropometric data were collected. A total of 160 infants (boys = 84) were assessed from birth to 4 months of age. Mean birth weight was 3.46 ± 0.39 kg % fat and fat-free mass significantly increased from birth to 4 months of age (P < 0.0001). Gender-specific %fat and total fat-free mass curves for infants from birth to 4 months of age were created. This study will be beneficial to health-care professionals in evaluating normal growth and nutritional patterns in the first months of life.     

Intestinal microbiota and secretory immunoglobulin A in feces of exclusively breast-fed infants with blood-streaked stools

Episodes of blood‐streaked stools are not uncommon in exclusively breast‐fed infants under 6 months of age. Such bleeding is thought to be associated with food protein‐induced proctocolitis, however the pathomechanism remains unclear. The aim of this study was to investigate intestinal microbiota and secretory immunoglobulin A in the feces of exclusively breast‐fed infants with blood‐streaked stools. Fecal specimens from 15 full‐term infants with blood‐streaked stools and 15 breast‐fed healthy infants were studied and the results compared. All infants had been delivered vaginally and exclusively breast‐fed. The fecal microbiota were investigated by phylogenetic analysis combined with culture methods for some bacterial species, and feces were assessed for the presence of fecal secretory immunoglobulin A by enzyme‐linked immunosorbent assay. Phylogenetic cluster analysis revealed four major clusters of fecal bacteria, cluster A being found only in healthy infants. The Bacteroides fragilis group was observed more frequently in controls than in patients (P < 0.05). In the controls, the predominant species belonging to the Enterobacteriaceae group was Escherichia coli, whereas in the patients it was Klebsiella (P < 0.05). Concentrations of secretory immunoglobulin A were high in one third of the healthy controls. In conclusion, the pathomechanism of rectal bleeding in exclusively breast‐fed infants may be related to differences in the composition of their intestinal flora.     

Reconstruction of 90Sr intake for breast-fed infants in the Techa riverside settlements

The Techa River (Southern Urals, Russia) was contaminated as a result of radioactive releases by the Mayak plutonium production facility during 1949-1956. The persons born after the onset of the contamination have been identified as the "Techa River Offspring Cohort" (TROC). The TROC has the potential to provide direct data on health effects in progeny that resulted from exposure of a general parent population to chronic radiation. The purpose of the present investigation is the estimation of (90)Sr intake from breast milk and river water in the period from birth to 6 months of life, necessary for an infant dose calculation. The investigation is based on all available data concerning radioactive contamination due to global fallouts and Mayak releases in the Southern Urals where extensive radiometric and radiochemical investigations of human tissues and environmental samples were conducted during the second half of the twentieth century. The strontium transfer factor from mother's daily diet to breast milk was estimated as 0.05 (0.01-0.13) d L(-1). Based on this transfer factor and data on (90)Sr water contamination, the average total (90)Sr intake for an infant born in the middle Techa River region was found to be equal to 60-80 kBq in 1950-1951. For the same period, calculations of (90)Sr intake using ICRP models gave values of 70-100 kBq. From 1952 onwards, the differences in intakes calculated using the two approaches increased, reaching a factor of 2-3 in 1953. The Techa River data provide the basis for improving and adapting the ICRP models for application to Techa River-specific population.     

Determination of selenium in serum by FI-HG-AAS and calculation of dietary intake

A method was developed for the determination of selenium concentration in serum by flow injection-hydride generation-atomic absorption spectrometry (FI-HG-AAS) following microwave digestion of serum samples and reduction of selenate to selenite. The detection limit of the method was 0.3 μg Se/L and the characteristic concentration, corresponding to the 0.0044 absorbance signal, was 0.12 μg Se/L. The results from the analysis of two Seronorm standard reference materials showed good agreement with the certified values. The method was then used to analyze selenium in sera of Austrian and Slovenian people for the calculation of dietary intakes. The selenium concentrations in sera of mothers at delivery, their neonates, and the male and female adults were 71 ± 14, 42 ± 6, 75 ± 21, and 65 ± 16 μg/L for the Austrians and 62 ± 15, 34 ± 7, 70 ± 12, and 66 ± 15 μg/L for the Slovenians. The dietary intakes of selenium of the mothers and the male and the female adults were calculated as 52, 37, and 46 μg/d for the Austrians and 45, 38, and 32 μg/d for the Slovenians.     

The food intake of rats during pregnancy and lactation

Quantities of food required by Sprague-Dawley rats during gestation and lactation and in the post-lactation period were examined. Rats allowed to eat ad libitum during pregnancy consumed quantities of food only slightly greater than the amount reported to be the average intake of pregnant Sprague-Dawley rats (20 g/day). Rats delivered their pups on day 22 or day 23 of the gestation period, but regardless of the day of delivery, the food intake of each rat decreased on day 21 of pregnancy and then decreased a second time on the day of parturition. During lactation, food consumption of the rats soon exceeded the amount reported as the average intake of lactating rats (30-35 g/day). Food intake was found to escalate from 12.2 +/- 3.1 g/rat on day 0 of lactation, the lowest intake in the study, to 94.4 +/- 23.7 g on day 21 of lactation. However, in the latter part of the lactation period, the intake represented the combined food intake of dams and pups. Eight days in the post-lactation period were required for food intake of dams to return to a level near that recorded at the beginning of pregnancy.     

Variation in nutrient intake of infants and its implications for collecting reliable dietary intake data

Sources of variance in dietary intake data for infants in the fourth to sixth months of life were examined. Twenty-eight mothers of infants in the Special Supplemental Food Program for Women, Infants, and Children gave 24-hr recall information on their infants' diets on 4 random days over approximately 1 month. ANOVA found no day of the week or sequence effects on nutrient variation. Variance was partitioned into between- and within-subject (residual) components. Interindividual variation exceeded intraindividual variation for all nutrients except vitamin C. Variance ratios ranged from 0.3 to 1.3. Calculations of 95% confidence limits for group and individual mean intakes indicated that, whereas a single recall would estimate the group mean within 20% for most nutrients, five recalls would be necessary for the same accuracy in individual means. Magnitude and patterning of variance components differ substantially from those found in studies of adults, suggesting that infant data collection strategies should be tailored to the unique nature of the infant diet.     

Effect of dietary selenium restriction on selected parameters of selenium status in men with high life-long intake

The influence of selenium (Se) restriction on disposition in plasma and urine fractions of infused (74)Se (selenite) was studied when adult males (Enshi City, Hubei Province, PRC) whose habitual daily Se intake is approximately 480 microg per day were transferred to Lichuan County, where the daily intake is approximately 30 microg. The subjects received an infusion (106 microg Se) on the day before consuming foods low in Se and a second infusion (113 microg Se) 63 days later. Blood and 24-hour urine samples were collected each day for 7 days after the first infusion and on days 22, 43, and 62 following the first infusion. Urine and blood were also collected daily for the next 7 days after the second infusion. Plasma total Se concentration increased for 7 days after each of the two infusions and urine Se decreased exponentially following both the first and second infusions. The excretion of trimethylselenonium followed the same pattern as the total urinary Se. Surprisingly, there was not a significant difference in selenite retention between the two infusion periods, and the data indicated that, regardless of the chemical form of Se present in various organs, its catabolism leading to excretion in urine followed the same pathway as that of selenite. Labeled Se was incorporated predominantly in the plasma selenoprotein P fraction and the half-life of Se in this fraction was determined to be 1.9 to 2.9 days. Thus, a longer depletion period is required in these subjects to obtain more significant changes.     

Intermittent suckling enables estrus and pregnancy during lactation in sows: effects of stage of lactation and lactation during early pregnancy

Previously we demonstrated that pre-ovulatory LH and post-ovulatory progesterone (P4) concentrations in plasma were low and embryo development was retarded when sows were induced to ovulate during lactation by submitting them to intermittent suckling (IS). The present study investigated whether this was due to: (1) stage of lactation when IS was initiated, and (2) continuation of IS post-ovulation. Multiparous Topigs40 sows were studied under three conditions: conventional weaning at Day 21 of lactation (C21; n = 30), intermittent suckling from Day 14 of lactation (IS14; n = 32), and intermittent suckling from Day 21 of lactation (IS21; n = 33). Sows were separated from piglets for 12 h daily during IS. IS sows were either weaned at ovulation or 20 d following ovulation. One-third (21/63) of the IS21 and C21 sows had already ovulated or had large pre-ovulatory follicles at Day 21 and were excluded from further study. Initiation of IS at Day 14 instead of Day 21 of lactation tended to reduce P4 at 7 d post-ovulation (P = 0.07), did not affect pregnancy rate, and tended to reduce embryo survival (P = 0.06). Continuation of IS during pregnancy resulted in lower P4 at 7 and 12 d post-ovulation, tended to reduce embryo weight and pregnancy rate (P < 0.10), whereas embryo survival was not affected. This study presents data for a population of sows in which follicle growth and ovulation are easily triggered under suckling conditions. Further, when these sows are bred during lactation, initiation of IS at 21 rather than 14 d of lactation with weaning at ovulation yields the most desirable reproductive performance.     

Relationship of dietary intake of fish and non-fish selenium to serum lipids in Japanese rural coastal community.

Several studies have suggested that dietary selenium deficiency may be associated with an increased risk of coronary heart disease (CHD). In the present study, 55 men and 71 women were selected from participants in a health examination in a rural coastal community in Japan. The mean dietary selenium intake calculated from the simple food frequency questionnaire (SFFQ) was 127.5 micrograms/day. Fish was the major source of dietary selenium and it contributed to 68.7% of the daily total. HDL cholesterol was higher in the middle selenium intake group and in the high selenium intake group than in the low selenium intake group in all subjects and for males, and a significant difference was found between the middle selenium intake group and the low selenium intake group. The atherogenic index was significantly higher in the low selenium intake group than in the middle selenium intake group and in the high selenium intake group in males. GPx activity, total cholesterol and triacylglycerols did not show any significant differences among the three different selenium intake groups. Dietary intake of non-fish Se had a positive correlation with HDL cholesterol, and an inverse correlation with the atherogenic index in all subjects and for females. On the other hand, dietary intake of fish-Se had no relationship with any serum lipids. Non-fish Se is an important factor in selenium status for the prevention of CHD.     

Energy intake,oxidative stress and antioxidant in mice during lactation

Reproduction is the highest energy demand period for small mammals, during which both energy intake and expenditure are increased to cope with elevated energy requirements of offspring growth and somatic protection. Oxidative stress life history theory proposed that reactive oxygen species(ROS) were produced in direct proportion to metabolic rate, resulting in oxidative stress and damage to macromolecules. In the present study, several markers of oxidative stress and antioxidants activities were examined in brain, liver, kidneys, skeletal muscle and small intestine in non-lactating(Non-Lac) and lactating(Lac) KM mice. Uncoupling protein(ucps) gene expression was examined in brain, liver and muscle. During peak lactation, gross energy intake was 254% higher in Lac mice than in Non-Lac mice. Levels of H2O2 of Lac mice were 17.7% higher in brain(P<0.05), but 21.1%(P<0.01) and 14.5%(P<0.05) lower in liver and small intestine than that of Non-Lac mice. Malonadialdehyde(MDA) levels of Lac mice were significantly higher in brain, but lower in liver, kidneys, muscle and small intestine than that of Non-Lac mice. Activity of glutathione peroxidase(GSH-PX) was significantly decreased in brain and liver in the Lac group compared with that in the Non-Lac group. Total antioxidant capacity(TAOC) activity of Lac mice was significantly higher in muscle, but lower in kidneys than Non-Lac mice. Ucp4 and ucp5 gene expression of brain was 394% and 577% higher in Lac mice than in Non-Lac mice. These findings suggest that KM mice show tissuedependent changes in both oxidative stress and antioxidants. Activities of antioxidants may be regulated physiologically in response to the elevated ROS production in several tissues during peak lactation. Regulations of brain ucp4 and ucp5 gene expression may be involved in the prevention of oxidative damage to the tissue.     

Allometric scaling of the elevation of maternal energy intake during lactation

The amount of resources provided by the mother before birth has important and long-lasting effects on offspring fitness. Despite this, there is a large amount of variation in maternal investment seen in natural populations. Life-history theory predicts that this variation is maintained through a trade-off between the benefits of high maternal investment for the offspring and the costs of high investment for the mother. However, the proximate mechanisms underlying these costs of reproduction are not well understood. Here we used artificial selection for high and low maternal egg investment in a precocial bird, the Japanese quail (Coturnix japonica) to quantify costs of maternal reproductive investment. We show that females from the high maternal investment lines had significantly larger reproductive organs, which explained their overall larger body mass, and resulted in a higher resting metabolic rate (RMR). Contrary to our expectations, this increase in metabolic activity did not lead to a higher level of oxidative damage. This study is the first to provide experimental evidence for metabolic costs of increased per offspring investment.     

Impact of dietary selenium intake on cardiac health: experimental approaches and human studies

Selenium, a dietary trace mineral, essential for humans and animals, exerts its effects mainly through its incorporation into selenoproteins. Adequate selenium intake is needed to maximize the activity of selenoproteins, among which glutathione peroxidases have been shown to play a major role in cellular defense against oxidative stress initiated by excess reactive oxygen species. In humans, a low selenium status has been linked to increased risk of various diseases, including heart disease. The main objective of this review is to present current knowledge on the role of selenium in cardiac health. Experimental studies have shown that selenium may exert protective effects on cardiac tissue in animal models involving oxidative stress. Because of the narrow safety margin of this mineral, most interventional studies in humans have reported inconsistent findings. Major determinants of selenium status in humans are not well understood and several nondietary factors might be associated with reduced selenium status. In this review, we discuss recent studies regarding the role of selenoproteins in the cardiovascular system, the effect of dietary intake on selenium status, the impact of selenium status on cardiac health, and the cellular mechanisms that can be involved in the physiological and toxic effects of selenium.     

Cadmium-induced alterations in the antioxidant defense system of the rat eye in relation to dietary selenium intake

Cytosolic activity of glutathione peroxidase (GSH-Px), selenium-independent GSH-Px, and catalase, thiobarbituric acid reactive substances (TBARS), and glutathione and selenium (Se) concentration were measured in ocular tissues of rats maintained on a low (0.05 ppm) or adequate (0.10 ppm) Se diet and treated with 0 or 25 ppm cadmium (Cd) in their drinking water for fourteen weeks. Feeding rats a low Se diet resulted in a significant decrease in GSH-Px activity when compared to rats maintained on adequate dietary Se, irrespective of Cd treatment. Se-independent GSH-Px activity of rats maintained at 0.05 ppm Se decreased 27% when compared to Se-adequate controls, whereas activity increased 38% in the Cd-treated low-Se group. When comparisons were made between ocular TBARS in rats maintained at either level of dietary Se and treated with 0 or 25 ppm Cd, a trend toward decreased amounts of TBARS in Cd-treated groups was observed. A significant decrease in ocular Se concentration occurred in rats fed 0.05 ppm Se when compared to the Se-adequate group. Administering Cd to the low-Se group increased ocular Se levels 100%. A negative correlation between ocular Se concentration and TBARS was observed, suggesting a possible alternate role for Se as an antioxidant in the eye.     

Metabolic syndrome during gestation and lactation: An important renal problem in dams. selenium renal clearance

BackgroundMetabolic syndrome (MS) in lactating dams leads to several cardiometabolic changes related to selenium (Se) status and selenoproteins expression which produce hypertension. However, little is known about the state of these dams’ kidney functions and their Se deposits.MethodsTwo experimental groups of dam rats were used: control (Se: 0.1 ppm) and MS (Fructose 65 % and Se: 0.1 ppm). At the end of lactation (21d postpartum) kidney weight and protein content, Se deposits, and the activity of the antioxidant selenoprotein glutathione peroxidase (GPx) were measured in dams. Kidney functional parameters: albuminuria, creatinine clearance, serum aldosterone and uric acid levels and water and electrolyte (Na⁺ and K⁺) balance were also evaluated. Systolic blood pressure (SBP) was measured.ResultsIn MS dams at the end of lactation Se deposits and GPx activity are higher in the kidney; however, lipid renal peroxidation appears, relative Se clearance increases, and the dams have lost Se by urine. MS dams have polyuria and polydipsia, high uric acid serum levels, albuminuria and high creatinine clearance, implying glomerular renal malfunction with protein loss. They also present hypernatremia, hypokalemia and hyperaldosteronemia, leading to high SBP; however, a natriuretic process is taking place.ConclusionSince these alterations appear, at least in part, to be related to oxidative stress in renal cells, Se supplementation could be beneficial to avoiding greater lipid renal oxidation during lactation.     

Effects of dietary energy intake during gestation and lactation on milk yield and composition of first, second and fourth parity sows

In order to determine the effects of a varied level of dietary energy intake during pregnancy and lactation on milk yield and composition, first, second and fourth parity sows (Large White x German Landrace) were provided with energy at a level of either: (i) 100% of ME requirement (MEreq) during pregnancy and lactation, (ii) 120% MEreq during pregnancy and 80% during lactation, and (iii) 80% MEreq during pregnancy and 120% during lactation. In spite of equal target levels feed analysis revealed that gestating first parity sows with 120/80 treatment combination and lactating sows of 80/120 treatment combination received 25, and 11-17% more digestible N than in the respective 100/100 treatment combination. Irrespective of this 120/80 sows responded with the highest milk DM, fat, and energy contents, and the lowest lactose concentrations whereas protein levels where not affected, irrespective of parity (p < 0.05). Milk yield of sows in 1st and 4th lactation was 85 and 106% of that in 2nd lactation, respectively. Average milk composition was 18.1% DM, 4.9% protein, 6.8% fat, 5.6% lactose, and 0.8% ash. Milk composition changes ceased at day 7 of lactation with a reduction of milk GE and protein, and an increase of lactose content. Concentrations of threonine, arginine, valine, leucine, tyrosine, phenylalanine, cystine, and tryptophan, as well as stearic, oleic, and linoleic acid were higher in colostrum than in milk at later lactation stages. In contrast, laurine, myristic, palmitic, and palmitoleic acids were lower concentrated in colostrum. In conclusion, these results illustrate the importance of body reserve mobilization for milk production in sows and indicate that low energy supply during gestation cannot be compensated by higher energy supply during lactation.     

Effects of dietary energy intake during gestation and lactation on milk yield and composition of first,second and fourth parity sows

Abstract

In order to determine the effects of a varied level of dietary energy intake during pregnancy and lactation on milk yield and composition, first, second and fourth parity sows (Large White × German Landrace) were provided with energy at a level of either: (i) 100% of ME requirement (MEreq) during pregnancy and lactation, (ii) 120% MEreq during pregnancy and 80% during lactation, and (iii) 80% MEreq during pregnancy and 120% during lactation. In spite of equal target levels feed analysis revealed that gestating first parity sows with 120/80 treatment combination and lactating sows of 80/120 treatment combination received 25, and 11 – 17% more digestible N than in the respective 100/100 treatment combination. Irrespective of this 120/80 sows responded with the highest milk DM, fat, and energy contents, and the lowest lactose concentrations whereas protein levels where not affected, irrespective of parity (p < 0.05). Milk yield of sows in 1st and 4th lactation was 85 and 106% of that in 2nd lactation, respectively. Average milk composition was 18.1% DM, 4.9% protein, 6.8% fat, 5.6% lactose, and 0.8% ash. Milk composition changes ceased at day 7 of lactation with a reduction of milk GE and protein, and an increase of lactose content. Concentrations of threonine, arginine, valine, leucine, tyrosine, phenylalanine, cystine, and tryptophan, as well as stearic, oleic, and linoleic acid were higher in colostrum than in milk at later lactation stages. In contrast, laurine, myristic, palmitic, and palmitoleic acids were lower concentrated in colostrum. In conclusion, these results illustrate the importance of body reserve mobilization for milk production in sows and indicate that low energy supply during gestation cannot be compensated by higher energy supply during lactation.     

Plasma selenium in preterm and term infants during the first 12 months of life

The goal of the present study was to prospectively assess the plasma selenium (Se) concentrations of term and preterm infants during the first year of life in relation to gestational age and nutrition.

Blood specimens were collected from orally formula-fed preterm infants (gestational age < 32 weeks, birth weight < 1500 g): 1.) in hospital and 2.) corrected for gestational age parallel to healthy term breast and formula-fed infants at the ages of 1, 4 and 12 months. All infants were fed according to a standardized nutritional concept, solids and follow-up formula were introduced at the age of 4 months.

Plasma selenium in preterm infants in hospital was 11.7 (6.5–20.8) g/l and 11.6 (8.8–16.7) g/l at 4 weeks corrected for gestational age. At the age of 4 months plasma selenium was still significantly lower than in the other groups: Preterm infants: 17.1 (10.4–30.5) g/l; formula-fed term infants: 31.3 (24.3–47.5) g/l; breast-fed term infants: 45.6 (27.1–65.1) g/l). The levels of breast-fed infants were significantly higher than those of both formula-fed groups up until the introduction of solids.

Preterm infants had significantly low plasma selenium levels up until a postnatal age of at least 6 months. The levels were lower than those of term infants fed an identical unsupplemented infant formula during the first 4 months of life. These data support routine monitoring in hospital and selenium supplementation of preterm infants, preferably in hospital before discharge.     

Rumination time and monitoring of health disorders during early lactation

The objective was to evaluate the association between changes in daily rumination time (dRT) and early stages of disease during early lactation and to assess the performance of two proposed disease detection indices. This cohort study included 210 multiparous Holstein cows at the University of Florida Dairy Unit. Cows were affixed with a neck collar containing rumination loggers providing rumination time. The occurrence of health disorders (mastitis, metritis, clinical hypocalcemia, depression/dehydration/fever (DDF), digestive conditions, lameness and clinical ketosis) was assessed until 60 days in milk. Two indices were developed to explore the association between dRT and disease: (i) Cow index (CIx), based on changes in dRT in the affected cow during the days before the diagnosis of health disorders; (ii) Mates index (MIx), index based on deviations in dRT relative to previous days and healthy pen mate cohorts. Subsequently, an alert model was proposed for each index (ACIx and AMIx) considering the reference alert cut-off values as the differences between average index values in healthy and sick cows for each specific disease. The sensitivity (SE) of ACIx detecting disease ranged from 42% (digestive conditions and DDF) to 80% (clinical hypocalcemia) with 84% specificity (SP). The SE of AMIx ranged from 46% (digestive conditions and DDF) to 100% (clinical hypocalcemia) with 85% SP. Consistent reductions in rumination activity, both within cow and relative to healthy mate cohorts, were observed for each health disorder at the day of diagnosis. However, the ability of the proposed algorithms for detecting each specific disease was variable.     

Copper,selenium, and zinc concentrations in human milk during the first three weeks of lactation

Human milk samples were analyzed by neutron activation analysis (NAA) for three essential trace elements (Cu, Se, and Zn). Mothers' milk samples were collected from 25 lactating mothers from the Central Hospital, Tripoli, Libya. The average concentration level of Cu, Se, and Zn declined from 0.84 +/- 0.06 mg/L, 104 +/- 9.46 microg/L, and 16.1 +/- 2.67 mg/L at d 0 to 0.39 +/- 0.045 mg/L, 41.8 +/- 6.66 microg/L, and 4.95 +/- 1.3 mg/L, respectively, at d 20 of lactation. Copper and Zn levels in the Libyan mothers' milk were in agreement with reported levels from other countries, whereas Se was at a higher level. The Cu daily intake level is slightly higher than the RDA (Recommended Daily Allowance) value. Selenium and Zn have higher intake levels than the RDA values but within the tolerable upper intake levels.