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1.
An 84-98-d study was conducted in young women to determine the effect of vitamin B-6-deficient diets on calcium and magnesium metabolism. A vitamin B-6-deficient formula diet fed initially was followed by either animal- or plant-source protein food diets containing four increasing amounts of vitamin B-6. Calcium balance was negative during vitamin B-6 depletion. Serum calcium was higher and calcium balance negative with the plant protein diets. Magnesium balance was negative during vitamin B-6 depletion due to increased urinary magnesium excretion. Urinary calcium decreased during vitamin B-6 depletion and increased as dietary vitamin B-6 increased. Urinary oxalate was significantly higher at the end than at the beginning of vitamin B-6 depletion and was higher with plant than animal protein diets. The results suggest that vitamin B-6 depletion may alter calcium and magnesium metabolism and that dietary components associated with the protein source may influence calcium retention.  相似文献   

2.
Vitamin B-12 deficiency and hyperhomocysteinemia alter the metabolism of trace elements. This study tested the hypothesis that there is a reverse relationship in which diets high in iron, copper, nickel and cobalt would influence vitamin B-12 deficiency outcomes including hyperhomocysteinemia. Piglets (German Landrace x Pietrain) were assigned to six groups of 8 and fed one of the following diets for 166 d: a vitamin B-12-adequate and folate-fortified diet (30 microg/kg vitamin B-12 and 0.5 mg/kg folate) with normal trace element concentrations or one of five vitamin B-12-free, folate nonsupplemented diets (0.36 mg/kg), with either normal trace element concentrations or high concentrations of iron (300 mg/kg), copper (30 mg/kg), cobalt (1 mg/kg) or nickel (6 mg/kg). Feed intake and weight gain did not differ significantly among the groups. Vitamin B-12-deficient pigs developed diminished serum and liver concentrations of vitamin B-12 and folate, an accumulation of iron in the liver and hyperhomocysteinemia. The magnitude of changes differed among vitamin B-12-deficient groups. Vitamin B-12-deficient pigs fed 6 mg/kg nickel had distinctly higher vitamin B-12 concentrations in liver and serum and 45% lower serum concentration of homocysteine than the corresponding deficiency group fed 1 mg/kg nickel; iron concentration in liver was completely normalized. Vitamin B-12-deficient pigs fed 1 mg/kg cobalt had 47% lower homocysteine concentrations in serum than the vitamin B-12-deficient group fed 0.13 mg/kg cobalt, but the vitamin B-12 status was unaffected. Supplementation of iron and copper did not affect these variables. The dietary manipulations had no detrimental effects on variables symptomatic of oxidative stress. The findings indicate a collaborative relationship between vitamin B-12 metabolism and the trace elements nickel and cobalt.  相似文献   

3.
Intake of energy zinc, copper, and vitamin B-6 and indexes of zinc, copper and vitamin B-6 status were determined for eight men who consumed a high-carbohydrate dehydrated ration for 31 days of high activity at moderate altitudes (2,400 to 4,300 m). Data were collected 2 months before exposure (PRE), four times during the month at moderate altitudes (ALT), and 1 month after return (RET). Mean (+/- standard error) energy intake was 2,725 +/- 215, 3,430 +/- 79, and 3,370 +/- 215 kcal/day during PRE, ALT, and RET, respectively. Zinc and copper intakes averaged 10.6 +/- 1.6 and 1.0 +/- 0.1 mg/day during PRE and increased significantly to 16.9 +/- 0.7 and 3.5 +/- 0.1 mg/day during ALT; zinc and copper intakes were 15.5 +/- 1.6 and 1.9 +/- 0.3 mg/day for RET, respectively. Similarly, vitamin B-6 intake was significantly higher during ALT (PRE = 2.2 +/- 0.5 mg/day; ALT = 4.2 +/- 0.4 mg/day; and RET = 2.6 +/- 0.4 mg/day) as compared with PRE and RET. No significant changes were noted for plasma zinc, copper, or their related proteins or plasma or erythrocyte pyridoxal-5'-phosphate. Finally, no changes in urinary excretion of zinc were observed. The results indicate that dehydrated rations provide zinc, copper, and vitamin B-6 in amounts above the Recommended Dietary Allowances. Such diets may be consumed for at least 1 month without compromising status for these nutrients.  相似文献   

4.
BACKGROUND: Previously we showed that women in rural Nepal experience multiple micronutrient deficiencies in early pregnancy. OBJECTIVE: This study examined the effects of daily antenatal micronutrient supplementation on changes in the biochemical status of several micronutrients during pregnancy. DESIGN: In Nepal, we conducted a randomized controlled trial in which 4 combinations of micronutrients (folic acid, folic acid + iron, folic acid + iron + zinc, and a multiple micronutrient supplement containing folic acid, iron, zinc, and 11 other nutrients) plus vitamin A, or vitamin A alone as a control, were given daily during pregnancy. In a subsample of subjects (n = 740), blood was collected both before supplementation and at approximately 32 wk of gestation. RESULTS: In the control group, serum concentrations of zinc, riboflavin, and vitamins B-12 and B-6 decreased, whereas those of copper and alpha-tocopherol increased, from the first to the third trimester. Concentrations of serum folate, 25-hydroxyvitamin D, and undercarboxylated prothrombin remained unchanged. Supplementation with folic acid alone or folic acid + iron decreased folate deficiency. However, the addition of zinc failed to increase serum folate, which suggests a negative inhibition; multiple micronutrient supplementation increased serum folate. Folic acid + iron + zinc failed to improve zinc status but reduced subclinical infection. Multiple micronutrient supplementation decreased the prevalence of serum riboflavin, vitamin B-6, vitamin B-12, folate, and vitamin D deficiencies but had no effect on infection. CONCLUSIONS: In rural Nepal, antenatal supplementation with multiple micronutrients can ameliorate, to some extent, the burden of deficiency. The implications of such biochemical improvements in the absence of functional and health benefits remain unclear.  相似文献   

5.
As part of a larger investigation to determine the effect of animal vs. plant proteins on the vitamin B-6 requirement of young women, clinical changes during vitamin B-6 depletion were documented. Eight healthy young women were confined to a metabolic unit and fed a defined formula diet nearly devoid of vitamin B-6 (less than 0.05 mg/d). Serial electroencephalographic (EEG) tracings, peripheral nervous system tests, periodontal evaluations, and biochemical measures of vitamin B-6 status were conducted. Within 12 d on the depletion diet, two of the eight women exhibited abnormal EEG tracings. These changes were readily reversed by repletion of vitamin B-6 at the 0.5-mg/d level. Biochemical measures reflected lowered vitamin B-6 status but were not predictive of the onset of EEG changes. No detectable alterations in oral or periodontal status were found, nor did plaque flora change markedly. This study is the first report of EEG changes occurring in women undergoing vitamin B-6 depletion and the first report to document EEG changes in adults within 12 d on a vitamin B-6-depletion regimen.  相似文献   

6.
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.  相似文献   

7.
Vitamin and mineral supplementation to athletes.   总被引:3,自引:0,他引:3  
Vitamin and mineral supplements are frequently used by competitive and recreational athletes. Dietary deficiencies of most vitamins are not very common among athletes except in those who restrict their food intake in order to maintain body weight. Vitamins most likely to be deficient in the diet are folate, B6, B12, and E. Biochemical evidence of vitamin deficiencies in some athletes have been reported for thiamine, riboflavin, and B6. When the diet is deficient, vitamin supplements may improve performance but are not likely to be effective if the dietary intake is adequate. Some female athletes' diets are low in calcium, iron, and zinc. Low calcium intake may reduce peak bone mass in young women. Iron deficiency may impair performance and needs to be corrected with an iron supplement. Zinc supplements that exceed the RDA interfere with the absorption of copper and lower HDL-cholesterol.  相似文献   

8.
Zinc and iron compete during intestinal absorption, but postabsorptive interactions between these nutrients are less clear. Understanding these interactions is important to determine when supplementation with iron or zinc is proposed. The effect of zinc supplementation (22 mg Zn/d as zinc gluconate) or of iron supplementation (100 mg Fe/d as ferrous sulfate) for 6 wk on iron and zinc metabolism and absorption was evaluated in young women with low iron reserves. Young adult women (ages 20-28 y), nonanemic but with low iron stores (plasma ferritin< 20 microg/L), participated in the 70-d study. The women were divided in two groups (zinc-supplemented, n = 11; iron-supplemented, n = 12). The supplements were taken at bedtime. Iron and zinc biochemical indices and intestinal absorption were measured on d 1 and 56. Radioiron and stable isotopes of zinc were used to measure iron and zinc absorption from a test meal. In the iron-supplemented group, blood hemoglobin, plasma ferritin and the percentage of transferrin saturation increased (P < 0.01). Zinc indices did not change. In the zinc-supplemented group, plasma ferritin and the percentage of transferrin saturation decreased (P < 0.05), whereas the plasma transferrin receptor and erythrocyte zinc protoprophyrin levels increased (P < 0.05). Plasma and urinary zinc also increased (P < 0.01). Iron absorption (%) from the test meal increased (P < 0.01), whereas zinc absorption (%) decreased (P < 0.01) compared with baseline in the Zn-supplemented women. Our results indicate that the use of iron supplements in women with marginal iron status improves iron indices with no effect on zinc status. However, use of a modest zinc supplement improves zinc indices, but also appears to induce a cellular iron deficiency and, possibly, further reduce iron status.  相似文献   

9.
The effects of starvation and refeeding of 2-wk-old turkey poults on serum and tissue levels of zinc, copper and iron were investigated. Serum concentrations of zinc and copper declined during 4 d of starvation. Refeeding for 24 h following a period of starvation restored serum copper to levels similar to those in the fed controls but failed to elevate zinc levels. Liver concentrations and total quantities of zinc, copper and iron increased throughout starvation. Refeeding the starved poults reduced hepatic metal concentrations but caused a further increase in total metal content. This was apparently related to the large increase in liver mass, and the effect was most pronounced in poults starved 1 d prior to refeeding. Starvation also caused an increased zinc concentration and content and a reduced copper content in the pancreas, duodenal mucosa and kidney. Iron content of the pancreas and kidney increased during starvation, but that of the duodenal mucosa declined. Starvation evoked a progressive increase in the cytosolic zinc concentration from liver, pancreas, duodenal mucosa and kidney. A major part of this increase was accounted for as zinc bound to metallothionein (MT). Refeeding rapidly reduced cytosolic and MT-bound zinc in each of these tissues. It was concluded that starvation and refeeding had major effects on tissue trace metal status. A function is proposed for MT during starvation as a mechanism for the conservation of body zinc stores. Zinc, released as a consequence of tissue catabolism, is repartitioned into a soluble storage site (MT), which can be rapidly mobilized to meet the demands of new tissue synthesis once anabolic metabolism resumes.  相似文献   

10.
孕妇微量元素和维生素状况研究   总被引:10,自引:0,他引:10  
对36名孕妇和40名育龄妇女进行膳食调查和锌、铜、锰、镉、维生素A、E和叶酸状况研究,结果显示,孕妇各营养素摄入量显著高于未孕妇女,但两者均未达到相应的供给量标准。孕妇血清锌、叶酸和发锰浓度显著低于未孕妇女,而血清铜、镉、维生素A和E浓度则显著高于未孕妇女,并随孕期进展显著增加。因此,孕期同时发生的血清锌降低和血清镉升高可能对胎儿生长发育为一潜在危害,幸而孕期逐渐增加的血清铜也可能与镉相拮抗。因此,在评估孕期锌、铜营养状况时,不可忽略镉的干扰作用。  相似文献   

11.
The etiology of anemia during pregnancy in rural Southern Ethiopia is uncertain. Intakes of animal-source foods are low and infections and bacterial overgrowth probably coexist. We therefore measured the dietary intakes of a convenience sample of Sidama women in late pregnancy who consumed either maize (n = 68) or fermented enset (Enset ventricosum) (n = 31) as their major energy source. Blood samples were analyzed for a complete blood count, vitamin B-12 and folate status, plasma ferritin, retinol, zinc, albumin, and C-reactive protein (CRP). The role of infection and gravida was also examined. Dietary intakes were calculated from 1-d weighed records. No cellular animal products were consumed. Of the women, 29% had anemia, 13% had iron deficiency anemia, 33% had depleted iron stores, and 74 and 27% had low plasma zinc and retinol, respectively. Only 2% had low plasma folate (< 6.8 nmol/L) and 23% had low plasma vitamin B-12 (< 150 pmol/L), even though 62% had elevated plasma methylmalonic acid (MMA) (> 271 nmol/L). None had elevated plasma cystathionine or total homocysteine (tHcys). Women with enset-based diets had higher (P = 0.052) plasma vitamin B-12 concentration and lower (P < 0.05) cell volume, plasma cystathionine, and retinol than women consuming maize-based diets, but mean hemoglobin, plasma ferritin, MMA, tHcys, and folate did not differ. Plasma zinc, followed by CRP (< or = 5 mg/L), gravida (< or = 4), and plasma ferritin (> or = 12 microg/L) status were major positive predictors of hemoglobin. Despite some early functional vitamin B-12 deficiency, there was no macrocytic anemia. Consumption of fermented enset may have increased vitamin B-12 levels in diet and plasma.  相似文献   

12.
The purpose of the study was determination of the effect of cellulose on the apparent absorption and tissue concentrations of iron, zinc and copper in growing rats. Male Wistar rats with initial body weight 108 +/- 2 g were fed during 6 weeks isocaloric diets containing 1%, 5% or 10% of dietary fibre. The diets contained about 18% protein (casein and wheat gluten 1:1) and iron 28 mg, zinc 17 mg and copper 4.5 mg per kg of diet. In the 2nd, 4th and 6th weeks of the experiment feaces were collected during 2 days. Mineral components of the diets, cases liver, spleen, kidneys and femur were determined by atomic absorption spectrophotometry. No significant differences were noted in diet intake or in body weight gain between these groups. Increased cellulose content in diet, that is 5% or 10%, reduced significantly the absolute and per cent apparent absorption of copper and its concentration in liver, which indirectly led to disturbances of iron metabolism. As a result, the concentration of haemoglobin was reduced and the hepatic iron reserve was raised. No adverse effect of cellulose was found on the apparent absorption of iron and zinc and on zinc concentration in the studied tissues. The per cent coefficients of apparent absorption of iron decreased during the experiment, while those of zinc and copper increased.  相似文献   

13.
A 75-day human metabolic study was conducted to evaluate the effects of 1 g supplements of phosphorus, either as orthophosphate or hexametaphosphate, alone and in combination with 810 mg calcium on zinc, iron and copper bioavailability in ten young men. An additional objective was to determine the effects of increasing dietary calcium on polyphosphate hydrolysis. All subjects consumed each of the five diets (basal, low calcium-high orthophosphate, low calcium-high polyphosphate, high calcium-high orthophosphate and high calcium-high polyphosphate) for 15 days. Increasing dietary calcium caused a significant decrease in polyphosphate hydrolysis; the calcium supplement stabilized hexametaphosphate and all of its' polyphosphate hydrolysis products except pyrophosphate. Both phosphate supplements caused significant decreases in iron absorption and retention at the lower level of calcium intake, but the hexametaphosphate exerted a substantially greater effect. Simultaneously supplementing the diet with calcium and orthophosphate caused a similar reduction in iron absorption and retention to that found at the lower level of calcium intake. The hexametaphosphate supplement was without significant effect on iron absorption and retention at the higher level of calcium intake, and caused a significant decrease in copper retention. Zinc retention was not significantly affected by any dietary treatment.  相似文献   

14.
Vitamin and trace element status of women with disordered eating   总被引:1,自引:0,他引:1  
We studied biochemical measures of vitamin B-6, zinc, and copper in a group of 96 women and vitamin A and vitamin E concentrations in 89 women, all suffering from an eating disorder. Twenty-three control subjects were studied. Eating-disorder patients not taking vitamin or mineral supplements had significantly higher plasma concentrations of vitamins A and E than did control subjects (also not taking supplements). No difference was found in indices indicating vitamin B-6 status or in plasma zinc or copper concentrations. Self-induced vomiting was the only significant predictor of upper-quartile vitamin A concentrations. Upper-quartile vitamin B-6 activations (indicating lower vitamin B-6 activity) were significantly predicted only by low actual body weight. These results suggest that supplementation of micronutrient intake needs only to be considered for those eating-disorder patients at low weight and then only with water-soluble vitamins.  相似文献   

15.
《Nutrition Research》1988,8(4):333-343
Six healthy young men were confined to a metabolic unit to study iron and copper absorption from constant diets containing 10 mg of iron and 3 mg of copper daily. Iron status of all the men was normal. The men were confined to a metabolic unit for 78 days. Absorption was determined twice during the study using iron and copper enriched with the stable isotopes 54Fe and 65Cu. Stable isotopes were analyzed by magnetic sector, thermal ionization mass spectrometry. Iron and copper balances were determined for two 21 day periods and blood parameters of iron and copper status were measured at the beginning and end of the study. Data of the young men were combined with data of elderly men studied earlier. Blood indicators reflected adequate iron status in all subjects at the end of the study and serum copper was in the normal range for all subjects. The following indicators of iron status differed significantly among subjects: hemoglobin, hematocrit, TIBC, ferritin, and serum transferrin. Urinary and serum copper also differed significantly among subjects. Neither iron nor copper absorption differed between age groups or study periods. Iron absorption differed significantly among individuals, but copper absorption did not.  相似文献   

16.
BACKGROUND: The interaction between iron and manganese in the gut is well characterized but iron status has not been shown to affect manganese absorption. OBJECTIVE: The objective of this study was to determine whether iron status as determined by serum ferritin concentrations affects manganese absorption, retention, balance, and status. DESIGN: The subjects were healthy young women; 11 had serum ferritin concentrations >50 microg/L and 15 had serum ferritin concentrations <15 microg/L. In a crossover design, subjects consumed diets that supplied either 0.7 or 9.5 mg Mn/d for 60 d. Manganese absorption and retention were assessed during the last 30 d of each dietary period by using an oral dose of 54Mn; balance was assessed simultaneously. RESULTS: Dietary manganese did not affect manganese status, but high serum ferritin depressed arginase activity. The interaction of ferritin status and dietary manganese affected 54Mn absorption and biological half-life. Absorption was greatest in subjects with low ferritin concentrations when they were consuming the low-manganese diet, and was least in subjects with high ferritin concentrations. Biological half-life was longest when subjects with high ferritin concentrations consumed the low-manganese diet, and was shortest in all subjects consuming the high-manganese diet. Manganese balance was only affected by the amount of manganese in the diet. CONCLUSIONS: These results show that iron status, as measured by serum ferritin concentration, is strongly associated with the amount of manganese absorbed from a meal by young women. When greater amounts of manganese are absorbed, the body may compensate by excreting manganese more quickly.  相似文献   

17.
Zinc and copper deficiency is associated with anaemia or iron deficiency and affects fetus growth and pregnant women during pregnancy. To examine iron, zinc and copper status of Chinese pregnant women with and without anaemia in the third trimester, 1185 subjects were enrolled for measurements of Hb, ferritin, transferrin, soluble transferrin receptor (sTfR), and serum iron, zinc and copper. The results showed that there were lower levels of ferritin (14.1 microg/L) and transferrin (3.33 g/L) in subjects with Hbor=101 g/L. sTfR levels in subjects with Hbor=120 g/L (38.5 nmol/L vs. 25.04 nmol/L, P<0.001). Serum iron was lower in subjects with Hbor=120 g/L (871 microg/L vs. 990 microg/L, P<0.01). Lower levels of serum iron and zinc were also found in anaemic (Hb<110 g/L) as compared with non-anaemic women (Hb>or=110 g/L). Frequencies of marginal deficiencies in serum iron and zinc were 41.58% and 51.05% respectively higher in anaemic than in non-anaemic subjects. Distribution of serum zinc and iron showed a decreasing trend as Hb decreased. Few anaemic as well as non-anaemic subjects had copper deficiency although copper and Hb levels were found inversely correlated and the ratio of copper/iron was higher in anaemic than in non-anaemic group. In conclusion, a lower level of serum zinc in anaemic pregnant women might be related to anaemia and iron deficiency during pregnancy. Therefore, combined zinc and iron supplementation should be recommended to Chinese pregnant women, especially those with anaemia.  相似文献   

18.
本文研究了牛横酸和维生素E对饲高脂家兔血清锌,铜,铁,钙的影响。结果表明,牛磺酸能显著增加高脂家兔出血清锌含量(P<0.05),而维生素E显著降低高脂家兔血清铜含量(P<0.01)。总的牛磺酸和维生素E都非常显著地降低了高脂家兔的血清铜/锌比值(P<0.01),对血清铁和钙无显著性影响。提示牛横酸和维生素E可能通过调节体内的锌,铜代谢而影响脂质代谢及动脉粥样硬化形成。  相似文献   

19.
Pregnant women in developing countries are vulnerable to multiple micronutrient deficiencies. We investigated their prevalence and seasonal variation as part of a baseline assessment in a population-based, maternal micronutrient supplementation trial conducted in the rural Southeastern plains of Nepal. Serum concentrations of 11 micronutrients were assessed in 1165 pregnant women in the 1st trimester before supplementation. Using defined cutoff values, the prevalence of deficiencies of vitamins A, E, and D were 7, 25, and 14%, respectively. Nearly 33% of the women were deficient in riboflavin, and 40 and 28% had serum vitamin B-6 and B-12 deficiencies, respectively. Only 12% of the women were folate deficient, but 61% were zinc deficient. The prevalence of low serum iron concentration was 40%, and 33% were anemic (hemoglobin < 110 g/L). Multiple micronutrient deficiencies were common among pregnant women. Over 10% of the pregnant women were both anemic and deficient in B-complex vitamins, whereas 22% of women were both anemic and zinc deficient. Only 4% of women had no deficiency, whereas approximately 20% of the women had 2, 3, or 4 deficiencies. Almost 18% of women had >/=5 deficiencies. Micronutrient status varied by season; it was generally best during the winter months, except for serum vitamin D concentration, which peaked during the hot summer and monsoon months. Women in rural South Asia are likely to begin a pregnancy with multiple micronutrient deficiencies that may vary with seasonality in micronutrient-rich food availability.  相似文献   

20.
The effect of surgical trauma on serum trace elements was studied in 10 patients undergoing coronary bypass surgery. After the initial decrease due to the hemodilution during operation serum iron, zinc, copper and selenium remained depressed for the immediate postoperative period. Zinc was still at significantly lower level 2 months after the operation. Low serum iron values were also observed. Changes in trace element concentrations were parallel with changes in the concentrations of their transport and binding proteins in the serum. The multielemental technique also measured nonessential bromide, which returned to initial levels in 7 days. Effects of trauma on metabolism, acute phase reaction with redistribution of zinc and copper and losses via increased urinary excretion explain the above changes. Development of a subclinical deficiency of zinc and possibly iron is suggested by the persistence of low serum levels during recovery after operation.  相似文献   

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