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Background: Selenium (Se) levels decrease in the circulation during acute inflammatory states and sepsis, and are inversely associated with morbidity and mortality. A more specific understanding of where selenoproteins and Se processing are compromised during insult is needed. We investigated the acute signaling response in selenoenzymes and Se processing machinery in multiple organs after innate immune activation in response to systemic lipopolysaccharide (LPS). Methods: Wild type (WT) adult male C57/B6 mice were exposed to LPS (5 mg/kg, intraperitoneal). Blood, liver, lung, kidney and spleen were collected from control mice as well as 2, 4, 8, and 24 h after LPS. Plasma Se concentration was determined by ICP-MS. Liver, lung, kidney and spleen were evaluated for mRNA and protein content of selenoenzymes and proteins required to process Se. Results: After 8 h of endotoxemia, plasma levels of Se and the Se transporter protein, SELENOP were significantly decreased. Consistent with this timing, the transcription and protein content of several hepatic selenoenzymes, including SELENOP, glutathione peroxidase 1 and 4 were significantly decreased. Furthermore, hepatic transcription and protein content of factors required for the Se processing, including selenophosphate synthetase 2 (Sps2), phosphoseryl tRNA kinase (Pstk), selenocysteine synthase (SepsecS), and selenocysteine lyase (Scly) were significantly decreased. Significant LPS-induced downregulation of these key selenium processing enzymes was observed in isolated hepatocytes. In contrast to the acute and dynamic changes observed in the liver, selenoenzymes did not decrease in the lung, kidney or spleen. Conclusion: Hepatic selenoenzyme production and Se processing factors decreased after endotoxemia. This was temporally associated with decreased circulating Se. In contrast to these active changes in the regulation of Se processing in the liver, selenoenzymes did not decrease in the lung, kidney or spleen. These findings highlight the need to further study the impact of innate immune challenges on Se processing in the liver and the impact of targeted therapeutic Se replacement strategies during innate immune challenge. [ABSTRACT FROM AUTHOR]

Background: Micronutrient deficiencies are common in patients undergoing gastric bypass. The effect of this type of surgery on zinc absorption and zinc status is not well known. Objective: The objective was to evaluate the effects of Roux-en-Y gastric bypass (RYGBP) on zinc status and zinc absorption at different stages after surgery. We hypothesized that zinc status would be significantly impaired after surgery and that this impairment would be less severe in subjects receiving increased supplemental zinc. We also hypothesized that zinc absorption would be lower after surgery. Design: Anthropometric and body-composition variables and dietary and biochemical indexes of zinc status and zinc absorption were determined in 67 severe and morbidly obese women [mean (±SD) age: 36.9 ± 9.8 y; BMI (in kg/m2): 45.2 ± 4.7] who underwent RYGBP. The subjects were randomly assigned to 1 of 2 vitamin-mineral supplementation groups. Measurements were made before and 6, 12, and 18 mo after surgery. Fifty-six subjects completed the 18-mo follow-up. Results: Mean plasma zinc, erythrocyte membrane alkaline phosphatase activity, and the size of the rapidly exchangeable zinc pool decreased after RYGBP. Percentage zinc absorption decreased significantly from 32.3% to 13.6% at 6 mo after RYGBP and to 21% at 18 mo after surgery. No effect of supplement type was observed. Conclusions: Zinc status is impaired after RYGBP, despite the finding that dietary plus supplemental zinc doubled recommended zinc intakes in healthy persons. Zinc absorption capacity is significantly reduced soon after RYGBP, with no major changes until 18 mo after surgery. © 2011 American Society for Nutrition. [ABSTRACT FROM AUTHOR]

Background: Micronutrient deficiencies are common in patients undergoing gastric bypass. The effect of this type of surgery on zinc absorption and zinc status is not well known. Objective: The objective was to evaluate the effects of Roux-en-Y gastric bypass (RYGBP) on zinc status and zinc absorption at different stages after surgery. We hypothesized that zinc status would be significantly impaired after surgery and that this impairment would be less severe in subjects receiving increased supplemental zinc. We also hypothesized that zinc absorption would be lower after surgery. Design: Anthropometric and body-composition variables and die- tary and biochemical indexes of zinc status and zinc absorption were determined in 67 severe and morbidly obese women [mean (± SD) age: 36.9 ± 9.8 y; BMI (in kglm2): 45.2 ± 4.7] who un- derwent RYGBP. The subjects were randomly assigned to I of 2 vitamin-mineral supplementation groups. Measurements were made before and 6, 12, and 18 mo after surgery. Fifty-six subjects com- pleted the 18-mo follow-up. Results: Mean plasma zinc, erythrocyte membrane alkaline phos- phatase activity, and the size of the rapidly exchangeable zinc pool decreased after RYGBP. Percentage zinc absorption decreased sig- nificantly from 32.3% tn 13.6% at 6 mo after RYGBP and to 21% at 18 mo after surgery. No effect of supplement type was observed. Conclusions: Zinc status is impaired after RYGBP, despite the finding that dietary plus supplemental zinc doubled recommended zinc intakes in healthy persons. Zinc absorption capacity is signifi- cantly reduced soon after RYGBP, with no major changes until 18 mo after surgery. [ABSTRACT FROM AUTHOR]

Background: Poor bioavailability of zinc from high-phytate diets is an important contributory factor to zinc deficiency in low-income populations. Objective: The objective of this study was to determine the effect of low-phytate maize consumption on zinc absorption. Design: The participants were apparently healthy children from the Central Highlands of Guatemala. Sixty children (20 per group) were randomly assigned to be fed only the low-phytate maize or 1 of 2 control maizes, the isohybrid wild-type maize or a local maize, for a 10-wk period. During the final week, the fractional absorption of zinc for all meals was measured during 1 d with the use of zinc stable isotopes and a dual isotope ratio technique based on urine enrichment data. Results: Mean ( + SD) phytate intakes for the low-phytate, wild-type, and local maize groups were 1536 ± 563, 2056 ± 517, and 2253 ± 687 mg/d, respectively. Corresponding zinc intakes were 8.6 ± 2.5, 8.1 ± 2.0, and 9.7 ± 2.6 mg/d, and the dietary phytate:zinc molar ratios were 18 ± 5, 26 ± 6, and 23 ± 5. Corresponding fractional absorptions of zinc were 0.32 ± 0.07, 0.28 ± 0.07, and 0.29 ± 0.06. The respective values for total absorbed zinc were 2.72 ± 0.88, 2.30 ± 0.96, and 2.78 ± 1.04 mg/d. No significant differences in either the fractional absorption of zinc or total absorbed zinc were seen between the maize groups. Conclusion: Under the conditions of the present study, zinc absorption was not increased by the long-term use of low-phytate maize in children whose major dietary staple is maize. [ABSTRACT FROM AUTHOR]

Background: Calcium fortification of maize has been achieved for millennia in Central America by the process of nixtamalization. Bioavailability of calcium is, however, compromised by phytate, which is present in large quantities in maize kernels and is only modestly reduced by nixtamalization. Objective: The objective was to compare the absorption of calcium from tortilla meals prepared from low-phytate maize with that from meals prepared from maize with typical phytate content. Design: At 1-mo intervals, 5 healthy adult women were fed 2 test meals of ≈140 g tortillas in lieu of breakfast. On one occasion, the tortillas were prepared from maize with ≈60% phytate reduction, and, on the other occasion, they were prepared from the matching isohybrid wild-type maize. Beginning midway through the test meal, 44Ca (0.3 mg/kg body wt) was administered in water as an extrinsic label; 42Ca (0.06 mg/kg body wt) was administered intravenously immediately after the test meal. Isotope ratios of 42Ca to 43Ca and of 44Ca to 43Ca were measured by inductively coupled plasma mass spectrometry in urine collected as an 8-h pool from the period 16-24 h after intravenous tracer administration and prepared by the oxalate precipitation method. Fractional absorption of calcium was determined by using a dual-isotope ratio technique. Results: Mean fractional absorption of calcium from tortillas prepared from the low-phytate maize (0.50 ± 0.03) was significantly (P<0.003) greater than that from tortillas prepared from the control maize (0.35 ± 0.07). Conclusion: The increase in the quantity of calcium absorbed could be of practical importance for calcium nutriture when the intake of dairy products is limited. [ABSTRACT FROM AUTHOR]

Background: Zinc supplements are used extensively in medicine and research and for public health purposes in the prevention and treatment of zinc deficiency. However, little is known about the efficiency of zinc utilization after different doses. Objective: The objective was to determine the relation between dose of aqueous zinc and absorbed zinc (AZ) in healthy adults. Design: Eight healthy adults (3 men and 5 women) aged 33.8 ± 9.8 y (x ± SD) received 3 pairs of zinc doses (2 and 5, 10 and 15, and 20 and 30 mg) in random order in 3 phases (1 pair per phase). There was a 3-wk washout between phases. Aqueous zinc sulfate labeled with 70Zn or 68Zn was orally administered in the postabsorptive state on days 1 and 6, respectively; intravenous 67Zn was administered 1 h after the first oral zinc dose. Two urine samples were collected daily from days 3 to 15; zinc isotopic ratios were determined by inductively coupled plasma mass spectrometry. Fractional absorption of zinc (FAZ) was determined by dual-isotope-tracer ratio; AZ was calculated by multiplying FAZ by dose. Results: Mean (±SD) AZ values at doses of 2.2, 5.2, 10.4, 15.2, 20.3, and 30.1 mg ingested Zn were 1.6 ± 0.4, 3.5 ± 1.3, 7.4 ± 1.0, 9.5 ± 2.2, 11.0 ± 4.4, and 11.2 ± 2.1 mg, respectively. A saturable dose-response model, the Hill equation, was selected to model the relation of AZ to ingested zinc. Parameter estimation by nonlinear regression predicted a maximum zinc absorption of 13 mg for larger doses. Conclusions: Increases in aqueous zinc doses >20 mg result in relatively small and progressively diminishing increases in AZ postabsorptively in healthy adults. [ABSTRACT FROM AUTHOR]

With dietary intervention studies, it is important to ensure that subjects adhere to the test diet. Current methods to monitor adherence have substantial limitations. Therefore, a dose-response test curve was constructed to determine whether small differences in serum Li could be detected in response to ingestion of variable Li doses indicative of full or partial dietary compliance. During 3 separate weeks, subjects consumed a test meal that included a single food containing Li citrate daily for 4 d. Doses of 250, 213, or 175 micromol Li were used each week to approximate compliance levels of 100, 85, and 70%. On d 4, blood samples were taken before and 1, 2, 3, 5, 7, 9, and 24 h after ingesting the test meal. Compared with the 100% dose, serum Li was significantly lower at all times after the 70% dose and at most times after the 85% dose. Data were analyzed to determine a cutoff value so that if a subject's serum Li was below that value, they would be declared noncompliant. The probability that a subject was declared to be noncompliant when in fact they were compliant was set to 0.05 (specificity was set to 0.95) and the probability of noncompliance (sensitivity) was estimated. Test performance was best in the 3- to 9-h range, for which 90-95% of subjects "noncompliant" at the 70% dose were identified. Li can be used as a biomarker to determine dietary compliance. Measuring serum Li 3-9 h after the last dose provides the highest sensitivity and specificity for noncompliance at doses <70%. [ABSTRACT FROM AUTHOR]

Determines fractional absorption of exogenous zinc and intestinal excretion of endogenous zinc in Chinese women of childbearing age with marginal dietary zinc intake. Role of intestine in zinc homeostasis maintenance; Health condition of the participants; How were zinc separated from urine and fecal samples.

Determines fractional absorption of exogenous zinc and intestinal excretion of endogenous zinc in Chinese women of childbearing age with marginal dietary zinc intake. Role of intestine in zinc homeostasis maintenance; Health condition of the participants; How were zinc separated from urine and fecal samples.

The intestine is the major route of excretion of endogenous zinc (Zn) and has a key role in maintaining Zn homeostasis. The principal objective of this paper is to provide an interpretative report of quantities of endogenous fecal Zn (EFZ) excreted by rural Guatemalan school children fed either normal or low phytate maize as their principal food staple. EFZ was measured by a Zn stable isotope technique. EFZ did not differ between control and low phytate maize groups. The overall EFZ (n = 53) was (mean +/- SD) 1.56 +/- 0.69 mg Zn/d or 0.07 +/- 0.03 mg Zn x kg body wt(-1) x d(-1). EFZ was not correlated with the quantity of Zn absorbed. The estimated EFZ at the level of absorption that matched the physiologic requirement (EFZ(PR)) did not differ from the above mean value. The EFZ(PR) of 0.07 +/- 0.03 mg Zn/kg body wt is twice the value currently used in the estimation of Dietary Reference Intakes. Supported by other recent childhood data, these results suggest that the current estimates of EFZ(PR) used in the calculation of Zn requirements for children are misleadingly low. [ABSTRACT FROM AUTHOR]

BACKGROUND: Extrinsic labeling techniques for determining fractional absorption of Zn (FAZ) have never been adequately evaluated. OBJECTIVE: The objective of this study, part of a larger project, was to compare results for determination of FAZextrinsic from a variety of different total diets using our own extrinsic labeling technique with results for simultaneous determination of FAZintrinsic. DESIGN: FAZ was determined for 5 days in 23 adults (Female) while consuming a constant rotating diet based on habitual intake. Zn intake ranged from 5-33mg/d, median 7.6mg/d. For extrinsic labeling, 70Zn tracer was administered gradually during the second half of each meal and absorption determined by our dual isotope tracer ratio (DITR) technique (67Zn infused IV) and by fecal monitoring (FM). FmZintrinsic was calculated from the sum of net absorption of Zn and intestinal excretion of endogenous Zn. RESULTS: Mean ± SD FAZ by DITR, FM and intrinsic were 0.28±0.11, 0.30±0.11 and 0.31±0.15, respectively (ANOVA, p=0.229). CONCLUSION: Small, not statistically significant, differences were found between these 3 methods for determining FAZ. [ABSTRACT FROM AUTHOR]