Effect of vitamin D supplementation as a single dose on the nutritional status of vitamin D. / Efecto de la suplementación con vitamina D en dosis única sobre el estado nutricional de vitamina D.

INTRODUCTION: Infants are a group at risk of vitamin D (VD) deficiency. The administration of 400 IU of VD per day during the first year of life does not achieve 100% adherence. A single dose of 100,000 IU of oral VD is safe in newborns. OBJECTIVE: To compare the effect of oral administration of VD between a single dose of 100,000 IU at one month of age vs daily doses of 400 IU on serum concentrations of VD, at 6 months of age. SUBJECTS AND METHOD: Randomized clinical trial, without masking. 84 healthy infants were included at 1 month of age, randomized to the study group (SG) receiving a single oral dose of 100,000 IU or to the control group (CG), who received daily oral doses of VD of 400 IU from the 1st to the 6th month of life. At 6 months of life, the serum concentration of VD was determined. RESULTS: 65 infants completed the study, 36 in SG and 29 in CG. No VD deficiency was found. VD insufficient was 5.5% and 6.8% in the SG and CG, respectively. The serum concentration of VD at six months of age was 38.8 ± 5.2 ng/ml and 39.7 ± 6.3 ng/ml for the SG and CG, respectively (NS). CONCLUSIONS: Supplementation of 100,000 IU of VD at one month age achieves serum concentrations of VD at 6 months of life similar to the administration of daily doses of 400 IU of VD from the 1st to the 6th month.

Clinical parameters, LysoGb3, podocyturia, and kidney biopsy in children with Fabry disease: is a correlation possible?

BACKGROUND: Fabry disease is an X-linked lysosomal storage disorder caused by α-galactosidase enzyme deficiency. We present clinical, biochemical, and histologic findings in children with classical phenotypic presentation of Fabry disease. METHODS: A retrospective analysis was performed using charts from 14 children with confirmed diagnosis. Clinical parameters were evaluated. Globotriaosylsphingosine -lysoGb3- detection in plasma, podocyturia, and kidney biopsy were carried out in all cases. RESULTS: All patients except one demonstrated at least one symptom of Fabry disease. LysoGb3 levels were above the normal range in all patients. Podocyturia was documented in all patients. Kidney biopsy revealed glomerular, interstitial, vascular, and tubular changes on light microscopy in nearly all patients. Electron microscopy showed podocyte inclusions in all patients. CONCLUSIONS: No difference in symptomatology was discernible between boys and girls. Podocyturia was detectable in children serving as a possible early marker of kidney injury. LysoGb3 was elevated in all cases, emphasizing the importance for diagnosis especially in female patients with normal αGal A activity. A possible association between lysoGb3 and symptom severity and histological involvement in kidney biopsy should be assessed in prospective studies with enough statistical power to determine if lysoGb3 can be used to predict nephropathy in children with Fabry disease.

[Assessment of dietary intake and urinary excretion of sodium and potassium in adults]. / Evaluación de la ingesta dietética y excreción urinaria de sodio y potasio en adultos.

BACKGROUND: Hypertension is associated with elevated sodium and low potassium intakes. The determination of sodium and potassium intake by dietary records is inaccurate, being its measurement from 24-h urine collection the reference method. AIM: To determine urinary sodium and potassium excretion in adults. To compare dietary sodium and potassium intake and their excretion from an isolated urine sample against the reference method. MATERIAL AND METHODS: Seventy healthy adults aged 35 ± 8 years with a body mass index 25 ± 2 kg/m² (36 women) were studied. Urine was collected over 24 h, including an isolated urine sample taken in fasting conditions. Additionally, three 24-h dietary records were performed. RESULTS: Reported sodium and potassium intake was 2,720 ± 567 and 1,068 ± 433 mg/day, respectively. In turn, urinary excretion of sodium and potassium was 4,770 ± 1,532 and 1,852 ± 559 mg/day, respectively. These latter values were significantly higher than those obtained by dietary records. Furthermore, the urinary sodium and potassium excretion estimated from an isolated urine sample was 4,839 ± 1,355 and 1,845 ± 494 mg/day, respectively. These values were similar to those obtained with a 24 h urine collection. CONCLUSIONS: Dietary records underestimated electrolyte intake when compared with the reference method. Using an isolated urine sample to estimate electrolyte intake may be a reliable alternative.

[Seasonal variations in the lipid profile of apparently healthy young adults living in Santiago, Chile]. / Variación estacional del perfil lipídico en adultos aparentemente sanos de Santiago, Chile.

The lipid profile is impacted by numerous factors. However, the seasonal variations in this profile have not been well-established in the southern hemisphere. The aim of this study was to determine the seasonal variation of the lipid profile in apparently healthy adults from Santiago, Chile. The study design was observational and prospective, involving 50 healthy volunteers of both genders, aged 23-62 years. The lipid profile was measured at monthly intervals over the course of one year. LDL was significantly higher in winter -spring than in summer- fall (p < 0.01). Conversely, HDL decreases significantly in winter (p < 0.05). We conclude that there are seasonal variations in the serum levels of LDL and HDL. The circannual pattern is characterized by increased levels of LDL in winter-spring and low levels of HDL in winter.

[Prevalence of deficiency and dietary intake of iron, zinc and copper in Chilean childbearing age women]. / Prevalencia de deficiencia y consumo de hierro, zinc y cobre en mujeres chilenas en edad fertil.

The aim of the present study was to evaluate anemia, the biochemical status and dietary adequacy of iron (Fe), zinc (Zn) and copper (Cu), in Chilean childbearing age women. We studied a convenience sample of 86 women aged 18 to 48 years from Santiago, Chile. We determined anemia and the micronutrient status through hemoglobin (Hb) mean corpuscular volume, transferrin saturation, zinc protoporphyrin, serum ferritin (SF), serum Zn and Cu. Dietary adequacy was estimated using a food frequency questionnaire. Of all women, 4.7% had Fe deficiency (ID) anemia, 21 % ID without anemia, 26 % depleted Fe stores and 48.3% normal Fe status. Obese women had higher SF (p<0.01) compared with those classified as having normal BMI. Also, showed higher Hb (p<0.05) concentrations compared with overweight and normal weight women. Partidipants showed 3.5 % and 2.3 % of Zn and Cu deficiency, respectively. Also, 95 %, 94 % and 99 % had adequate intake of Fe, Zn and Cu respectively, according to EAR cut points. There were no significant differences in micronutrients intake across different nutritional status. There was a low prevalence of anemia, Fe, Zn and Cu deficiency. A high percentage of women reached micronutrient adequacy. However, 47% of women had ID without anemia and Fe depleted stores.

Low prevalence of iron deficiency anemia between 1981 and 2010 in Chilean women of childbearing age.

OBJECTIVE: To determine the prevalence of anemia and iron status among Chilean women of childbearing age between 1981 and 2010. MATERIALS AND METHODS: Calculation of the prevalence of anemia and iron status was based on multiple cross-sectional iron absorption studies performed in 888 women during this period of time. All studies included measurements of hemoglobin, mean corpuscular volume, zinc protoporphyrin, percentage of transferrin saturation and serum ferritin. Data were grouped by decade (1981-1990, 1991-2000, and 2001-2010). RESULTS: Prevalence of anemia for these decades was 9, 6 and 10%, respectively (p=NS). Iron deficiency anemia was the main cause of anemia in all periods (55, 85 and 75%, respectively; p=NS). A high prevalence of women with normal iron status was observed for all periods (64, 69, and 67, respectively; p=NS). Prevalence of iron deficiency without anemia in 1981-1990, 1991-2000 and 2001-2010 was 7, 20 and 12%, respectively (p<0.05). Finally, prevalence of iron depleted stores was 20, 6 and 10%, respectively (p<0.05). CONCLUSIONS: Prevalence of iron deficiency anemia in Chilean women of childbearing age was mild between 1981 and 2010. More than 60% of childbearing age women presented normal iron status in all periods. However, prevalence of iron depleted stores was moderate during 1981-1990, and was mild during 1991-2000 and 2001-2010.

Absorption of iron from ferritin is independent of heme iron and ferrous salts in women and rat intestinal segments.

Ferritin iron from food is readily bioavailable to humans and has the potential for treating iron deficiency. Whether ferritin iron absorption is mechanistically different from iron absorption from small iron complexes/salts remains controversial. Here, we studied iron absorption (RBC (59)Fe) from radiolabeled ferritin iron (0.5 mg) in healthy women with or without non-ferritin iron competitors, ferrous sulfate, or hemoglobin. A 9-fold excess of non-ferritin iron competitor had no significant effect on ferritin iron absorption. Larger amounts of iron (50 mg and a 99-fold excess of either competitor) inhibited iron absorption. To measure transport rates of iron that was absorbed inside ferritin, rat intestinal segments ex vivo were perfused with radiolabeled ferritin and compared to perfusion with ferric nitrilotriacetic (Fe-NTA), a well-studied form of chelated iron. Intestinal transport of iron absorbed inside exogenous ferritin was 14.8% of the rate measured for iron absorbed from chelated iron. In the steady state, endogenous enterocyte ferritin contained >90% of the iron absorbed from Fe-NTA or ferritin. We found that ferritin is a slow release source of iron, readily available to humans or animals, based on RBC iron incorporation. Ferritin iron is absorbed by a different mechanism than iron salts/chelates or heme iron. Recognition of a second, nonheme iron absorption process, ferritin endocytosis, emphasizes the need for more mechanistic studies on ferritin iron absorption and highlights the potential of ferritin present in foods such as legumes to contribute to solutions for global iron deficiency.

Administration of high doses of copper to capuchin monkeys does not cause liver damage but induces transcriptional activation of hepatic proliferative responses.

Liver cells respond to copper loading upregulating protective mechanisms. However, to date, except for liver content, there are no good indicators that identify individuals with excess liver copper. We hypothesized that administering high doses of copper to young (5.5 mg Cu · kg⁻¹ . d⁻¹) and adult (7.5 mg Cu · kg⁻¹ . d⁻¹) capuchin monkeys would induce detectable liver damage. Study groups included adult monkeys (2 females, 2 males) 3-3.5 y old at enrollment treated with copper for 36 mo (ACu); age-matched controls (1 female, 3 males) that did not receive additional copper (AC); young monkeys (2 female, 2 males) treated from birth with copper for 36 mo (YCu); and young age-matched controls (2 female, 2 males) that did not receive additional copper (YC). We periodically assessed clinical, blood biochemical, and liver histological indicators and at 36 mo the hepatic mRNA abundance of MT2a, APP, DMT1, CTR1, HGF, TGFß, and NFκΒ only in adult monkeys. After 36 mo, the liver copper concentration was 4-5 times greater in treated monkeys relative to controls. All monkeys remained healthy with normal routine serum biochemical indices and there was no evidence of liver tissue damage. Relative mRNA abundance of HGF, TGFß and NFκB was significantly greater in ACu than in AC monkeys. In conclusion, capuchin monkeys exposed to copper at doses up to 50 times the current upper level enhanced expression of genes related to inflammation and injury without clinical, blood biochemical, or histological evidence of liver damage.

Chaperones CCS, ATOX and COXIV responses to copper supplementation in healthy adults.

Assessment of proteins in blood and other tissues has failed to identify markers of early copper effects on health. Studies in animal models show that chaperone of SOD (CCS) respond to changes of copper status. Evidence about other copper chaperones (COXIV, ATOX) is not clear. The aim of this study was to assess by means of an in vitro challenge the mRNA relative abundance of ccs, sod1, coxIV, mtIIa and atox in peripheral mononuclear cells (PMNCs) obtained from healthy individuals, acutely and chronically supplemented with small-to-moderate amounts of copper. Healthy participants received 8 mg Cu/d (supplemented group, SG) or placebo, (placebo group, PG) for 2 months. Biochemical indicators were assessed at basal (T0) and after 2 (T2) and 60 days (T60). At these times PMNCs were obtained, challenged with 1, 5 or 20 µM Cu-histidine for 20 h and the mRNA relative abundance of the selected genes assessed by real time PCR. The results showed that at T0, intracellular copper was not different between experimental and control groups. This increased at T2 and T60 when the copper in the media increased (two-way ANOVA, P < 0.001). In PG, CCS mRNA transcripts showed no significant changes (two-way ANOVA) at T2 and T60. In SG, CCS changed by treatment, time and interaction (two-way ANOVA, all P < 0.001). SOD, ATOX and COXIV expressions changed in both PG and SG showing various patterns of response, requiring further study. MTII responded as expected. We conclude that using healthy individuals as a human model, CCS but not SOD, ATOX or COXIV responded consistently to controlled changes of copper availability in an in vitro copper challenge.

Acute inhibition of iron bioavailability by zinc: studies in humans.

Iron (Fe) and zinc (Zn) deficiencies constitute two of the most important nutritional and public health problems affecting developing countries. Combined supplementation or fortification with Zn and Fe are strategies that can be used to improve the Zn and Fe status of a population. However, there is concern about potential negative interactions between these two micronutrients due to a competitive binding to DMT1 and Zip14 transporter. Studies performed in humans have shown an inhibitory effect of Zn on Fe absorption when both minerals are given together as a solution in fasting conditions. We found that at low doses of iron (0.5 mg) the threshold for the inhibition of iron bioavailability was at a Zn:Fe wt/wt ratio ≥5.9:1, whereas at higher doses of Fe (10 mg) this inhibition occurred at 1:1 Zn:Fe wt/wt ratio. This differential response could be explained by the variation in the abundance of both cations as they compete for a limited number of shared transporters at the enterocyte. Conflicting results have been obtained when this interaction was studied in different food matrices. A negative interaction was not observed when Fe and Zn were provided in a composite hamburger meal, premature formula, human milk, or cow milk. A decrease on Fe absorption was observed in only 1 of 3 studies when Fe and Zn were supplied in wheat flour. The possibility of a negative interaction should be considered for supplementation or fortification programs with both microminerals.

Calcium does not inhibit the absorption of 5 milligrams of nonheme or heme iron at doses less than 800 milligrams in nonpregnant women.

Calcium is the only known component in the diet that may affect absorption of both nonheme and heme iron. However, the evidence for a calcium effect on iron absorption mainly comes from studies that did not isolate the effect of calcium from that of other dietary components, because it was detected in single-meal studies. Our objective was to establish potential effects of calcium on absorption of nonheme and heme iron and the dose response for this effect in the absence of a meal. Fifty-four healthy, nonpregnant women were selected to participate in 4 iron absorption studies using iron radioactive tracers. We evaluated the effects of calcium doses between 200 and 1500 mg on absorption of 5 mg nonheme iron (as ferrous sulfate). We also evaluated the effects of calcium doses between 200 and 800 mg on absorption of 5 mg heme iron [as concentrated RBC (CRBC)]. Calcium was administered as calcium chloride in all studies and minerals were ingested on an empty stomach. Calcium doses ≥1000 mg diminished nonheme iron absorption by an average of 49.6%. A calcium dose of 800 mg diminished absorption of 5 mg heme iron by 37.7%. In conclusion, we demonstrated an isolated effect of calcium (as chloride) on absorption of 5 mg of iron provided as nonheme (as sulfate) and heme (as CRBC) iron. This effect was observed at doses higher than previously reported from single-meal studies, starting at ~800 mg of calcium.

Effect of dietary protein on heme iron uptake by Caco-2 cells.

OBJECTIVE: To study heme iron bioavailability and the role of dietary protein (animal and vegetable) on iron uptake using an in vitro model (Caco-2 cell line). METHODS: Caco-2 cells were seeded in bicameral chambers with different animal (beef, chicken or fish) or vegetable (peas, lentils, and soybeans) proteins or with pure animal (collagen and casein) or vegetable (gliadin, zein, and glutein) protein extracts. The effect of each protein over heme iron absorption was assessed. RESULTS: Intact heme uptake was higher than either heme plus albumin or digested heme plus albumin, but lower than digested heme. White meal exerted the highest inhibitory effect on hemin uptake. Heme iron uptake decreased in the presence of all legume extracts, but was not significantly different among them (one-way ANOVA, NS). Pure animal (collagen and casein) and vegetable (zein and glutelin) proteins increased heme iron uptake, except for gliadin. CONCLUSION: Animal and vegetable protein in general decreased heme iron uptake. However, purified animal and vegetable protein induce an increase in heme iron uptake.

Micronutrient deficiencies in patients with typical and atypical celiac disease.

OBJECTIVE: The extent of the digestive/absorptive involvement in atypical presentation of celiac disease (CD) is not always clear. The aim of the study was to assess nutritional status of iron (Fe), copper (Cu), and zinc (Zn) in patients with typical CD (TCD) and atypical CD (ACD). PATIENTS AND METHODS: A cross-sectional study was done in patients with TCD, ACD, and healthy controls (HC). Hemoglobin, serum ferritin, free erythrocyte protoporphyrin, Fe, Cu, ceruloplasmin, Zn, anti-endomysial antibodies, and anti-tissue transglutaminase antibodies were measured. Data were analyzed by Kruskal-Wallis, principal component analysis, and linear discriminant analysis. RESULTS: : One hundred nine individuals were studied (54 TCD, 19 ACD, 36 HC); mean age  ±  standard deviation was 23 ± 15.8 (range 1.6-75.4) years. Median and range of hemoglobin were 12.8 g/dL (8.1-17.6) in TCD, 12.4 g/dL (10.5-14.5) in ACD, and 13.6 g/dL (11.1-16.7) in HC (P < 0.0001); serum ferritin was 17.7 µg/L (2.9-157), 10.8 µg/L (2.7-39.8), and 28.7 µg/L (4.5-127.2), respectively (P < 0.01). Cu was 105 µg/dL (60-185), 97.5 µg/dL (40-130), and 125 µg/dL (80-205), respectively (P < 0.05). Ceruloplasmin was 21.6  mg/dL (14.2-73.2), 22.6  mg/dL (0.9-34.3), and 32.1 mg/dL (5.8-72.6), respectively (P < 0.01). There were no differences in Fe, free erythrocyte protoporphyrin, and Zn. Principal component analysis showed that 58% of observed variability was explained by Fe and Cu indicators. Linear discriminant analysis revealed differences between CD and HC (P < 0.0001), with high values of correct classification for TCD (73%) and HC (72%), but not ACD (16%), which were mostly classified as TCD (79%). CONCLUSIONS: Deficiency of micronutrients was found both in typical as well as in atypical cases.

[Prevalence of zinc and copper deficiencies in older subjects living in Metropolitan Santiago]. / Prevalencia de las deficiencias de zinc y cobre en adultos mayores de la Región Metropolitana de Santiago.

BACKGROUND: Older subjects have a high risk of developing zinc and copper deficiencies. AIM: To determine the prevalence of copper and zinc deficiencies in adults aged over 60 years, living in Metropolitan Santiago. SUBJECTS AND METHODS: Analyses were performed using anonymous serum samples from older subjects living in Santiago, Chile, who participated in the multicenter project SABE. Of the studied subjects, 49.3% had enough left over serum to measure serum zinc and copper concentrations by atomic absorption spectrometry. RESULTS: A total of 444 men and 198 women were studied. A positive correlation between serum zinc and copper was found in both women (r = 0.44, p < 0.001) and men (r = 0.48, p < 0.001). There were no differences in serum zinc concentration by sex and age. The prevalence of subnormal serum zinc valúes was 66.9% in women and 66.7% in men. Women had a significantly higher serum copper valúes than men (p < 0.02) and there were no differences by age. Prevalence of subnormal serum copper valúes was higher in women than in men (32.9 and 23.7% respectively, p < 0.05). Women had significantly higher copper I zinc serum ratio than men (p < 0.001). CONCLUSIONS: Older people living in Metropolitan Santiago have a high prevalence of copper and zinc deficiencies.

Exploratory Study: Excessive Iron Supplementation Reduces Zinc Content in Pork without Affecting Iron and Copper.

The aim of this work was to determine in an exploratory manner the effect of excessive iron supplementation on iron, zinc, and copper contents in pork and pork offal. Pigs averaging 50 days in age and 15 ± 1.3 kg body weight were allocated to a control group (500 ppm dietary Fe) and a supplemental group (3000 ppm dietary Fe). After an iron supplementation period of 60 days, blood samples were analyzed to determine iron biomarkers, serum copper, and zinc contents. Animals were slaughtered to assess total iron, non-heme iron, heme iron, zinc, and copper contents in samples of nine meat cuts and some offal. Iron supplementation improved the iron status in pigs with increased hemoglobin and hematocrit, but did not affect serum levels of iron, zinc, and copper. Iron supplementation did not affect the heme and non-heme iron contents of the different meat cuts. Zinc contents decreased by 32-55% in meat cuts, where iron content increased in the liver, spleen, kidneys, and pancreas. No differences of zinc and copper were observed in offal samples. High concentrations of iron supplementation reduce zinc content in pork.

Zinc absorption and zinc status are reduced after either sleeve gastrectomy or Roux-en-Y gastric bypass in premenopausal women with severe obesity studied prospectively over 24 postoperative months.

BACKGROUND: Roux-en-Y gastric bypass (RYGBP) is known to reduce zinc absorption; the effects of vertical sleeve gastrectomy (SG) and its long-term implications on zinc absorption have not yet been studied. OBJECTIVE: The aim was to evaluate the effects of SG and RYGBP on zinc absorption and zinc status in premenopausal women with severe obesity up to 24 mo after surgery. METHODS: Twenty-six premenopausal women undergoing SG [BMI (in kg/m2): 37.3 ± 3.2] and 32 undergoing RYGBP (BMI: 42.0 ± 4.2) were studied. A series of anthropometric, dietary, and zinc status parameters (plasma and hair zinc), and the size of the exchangeable zinc pool (EZP), as well as percentage zinc absorption from a standardized dose using a stable isotope methodology were evaluated in the patients before the surgical procedure and at 12 and 24 mo after SG or RYGBP. SG patients received 15 mg and RYGBP received 25 mg of supplemental Zn/d. RESULTS: In premenopausal women, zinc absorption was decreased by 71.9% and 52.0% in SG and RYGBP, respectively, 24 mo postsurgery, compared with initial values. According to 2-factor repeated-measures ANOVA, time effect was significant (P = <0.0001), but not time × group interaction (P = 0.470). Plasma zinc below the cutoff point of 70 µg/dL increased from 0 to 15.4% and 38.1% in SG and RYGBP, respectively. Mean EZP was significantly reduced 24 mo after surgery, although no time × group interactions were observed. Hair zinc did not change across time or between groups. CONCLUSIONS: Both SG and RYGBP have profound effects on zinc absorption capacity, which are not compensated for after 24 mo. Although zinc absorption reduction was similar in both types of surgeries, plasma zinc was more affected in RYGBP than SG, despite greater zinc supplementation in RYGBP.This trial was registered at http://www.isrctn.com as ISRCTN31937503.

Changes in bone mineral density, body composition and adiponectin levels in morbidly obese patients after bariatric surgery.

BACKGROUND: Gastric bypass surgery (GBP) is increasingly used as a treatment option in morbid obesity. Little is known about the effects of this surgery on bone mineral density (BMD) and the underlying mechanisms. To evaluate changes on BMD after GBP and its relation with changes in body composition and serum adiponectin, a longitudinal study in morbid obese subjects was conducted. METHODS: Forty-two women (BMI 45.0 +/- 4.3 kg/m(2); 37.7 +/- 9.6 years) were studied before surgery and 6 and 12 months after GBP. Percentage of body fat (%BF), fat-free mass (FFM), and BMD were measured by dual-energy X-ray absorptiometry and serum adiponectin levels by RIA. RESULTS: Twelve months after, GBP weight was decreased by 34.4 +/- 6.5% and excess weight loss was 68.2 +/- 12.8%. Significant reduction (p < 0.001) in total BMD (-3.0 +/- 2.1%), spine BMD (-7.4 +/- 6.8%) and hip BMD (-10.5 +/- 5.6%) were observed. Adiponectin concentration increased from 11.4 +/- 0.7 mg/L before surgery to 15.7 +/- 0.7 and 19.8 +/- 1.0 at the sixth and twelfth month after GBP, respectively (p < 0.001). Thirty-seven percent of the variation in total BMD could be explained by baseline weight, initial BMD, BF reduction, and adiponectin at the twelfth month (r (2) = 0.373; p < 0.001). Adiponectin at the twelfth month had a significant and positive correlation with the reduction of BMD, unrelated to baseline and variation in body composition parameters (adjusted correlation coefficient: r = 0.36). CONCLUSION: GBP induces a significant BMD loss related with changes in body composition, although some metabolic mediators, such as adiponectin increase, may have an independent action on BMD which deserves further study.

Caco-2 intestinal epithelial cells absorb soybean ferritin by mu2 (AP2)-dependent endocytosis.

Iron deficiency, a condition currently affecting approximately 3 billion people, persists in the 21st century despite half a millennium of medical treatment. Soybean ferritin (SBFn), a large, stable protein nanocage around a mineral with hundreds of iron and oxygen atoms, is a source of nutritional iron with an unknown mechanism for intestinal absorption. Iron absorption from SBFn is insensitive to phytate, suggesting an absorption mechanism different from for the ferrous transport. Here, we investigated the mechanism of iron absorption from mineralized SBFn using Caco-2 cells (polarized in bicameral inserts) as an intestinal cell mode and analyzed binding, internalization and degradation with labeled SBFn ((131)I or fluorescent labels), confocal microscopy, and immunoanalyses to show: 1) saturable binding to the apical cell surface; dissociation constant of 7.75 +/- 0.88 nmol/L; 2) internalization of SBFn that was dependent on temperature, concentration, and time; 3) entrance of SBFn iron into the labile iron pool (calcein quenching); 4) degradation of the SBFn protein cage; and 5) assembly peptide 2 (AP2)-/clathrin-dependent endocytosis (sensitivity of SBFn uptake to hyperosmolarity, acidity, and RNA interference to the mu(2) subunit of AP2), and resistance to filipin, a caveolar endocytosis inhibitor. The results support a model of SBFn endocytosis through the apical cell membrane, followed by protein cage degradation, mineral reduction/dissolution, and iron entry to the cytosolic iron pool. The large number of iron atoms in SBFn makes iron transport across the cell membrane a much more efficient event for SBFn than for single iron atoms as heme or ferrous ions.

CCS and SOD1 mRNA are reduced after copper supplementation in peripheral mononuclear cells of individuals with high serum ceruloplasmin concentration.

The limits of copper homeostatic regulation in humans are not known, making it difficult to define the milder effects of early copper excess. Furthermore, a robust assay to facilitate the detection of early stages of copper excess is needed. To address these issues, we assessed changes in relative mRNA abundance of methallothionein 2A (MT2A), prion (PrP), amyloid precursor-like protein 2 (APLP2), Cu/Zn superoxide dismutase (SOD1) and its copper chaperone (CCS) in peripheral mononuclear cells (PMNCs) from healthy adults representing the 5% highest and lowest extremes in the distribution curve of serum ceruloplasmin (Cp) concentrations of 800 individuals. The intracellular Cu content was also determined. PMNCs were isolated from individuals before and after exposure to a single daily dose of 10 mg Cu (as CuSO(4)) for 2 months. Results showed that although there were fluctuations in serum Cp values of the samples assessed before copper exposure, no significant differences were observed in cell copper content or in the relative abundance of MT2A, PrP and APLP2 transcripts in PMNCs. Also, these values were not modified after copper supplementation. However, CCS and SOD1 mRNA levels were reduced in PMNCs after copper supplementation in the individuals with the high Cp values, suggesting that they should be further explored as biomarkers of moderate copper overload in humans.

Supplementation with zinc between meals has no effect on subsequent iron absorption or on iron status of Chilean women.

OBJECTIVE: Studies on the effect of zinc (Zn) supplementation on iron absorption and iron status have shown mixed results. We investigated the effect of daily supplementation with 20 mg of Zn for a period of 2 mo on iron absorption and iron status of Chilean women. METHODS: Forty-four non-anemic, clinically healthy women 35 to 45 y of age were randomly selected to receive daily 20 mg of Zn, as Zn sulfate, or a placebo between meals for a period of 2 mo. Iron and zinc biochemical indicators and iron absorption studies were assessed at baseline and at the end of the study. Iron absorption was measured using the double radioisotopic technique. RESULTS: The geometric mean (range +/- 1 standard deviation) absorption of iron before supplementation between the Zn-supplemented and placebo groups was similar (31.2, 11.2 +/- 86.3, versus 27.4, 14.4 +/- 52.2, respectively, P = 0.97). Absorption increased significantly after the 2-mo supplementation period (P = 0.049), but there were no group-wise differences at the end of the trial (34.4, 17.5 +/- 67.3, versus 39.8, 20.9 +/- 75.8, respectively, P = 0.97). The geometric mean plasma Zn concentrations did not change significantly in either group during the course of the study (P = 0.47). There was no significant effect of Zn supplementation on any of the iron indicators studied. CONCLUSION: Supplementation of 20 mg of Zn between meals for a period of 2 mo had no effect on subsequent iron absorption or iron status of Chilean women.