Selenium in diet, blood, and toenails in relation to human health in a seleniferous area

To determine whether high dietary selenium intake was associated with adverse effects, selenium in diet, blood, and toenails was studied in relation to human health in adults residing in western South Dakota and eastern Wyoming. Over a 2-y period 142 subjects were recruited from households selected at random and from ranches where unusually high selenium intakes were suspected. Subjects completed health questionnaires, underwent physical examinations, provided blood samples for clinical assessment, and provided blood, urine, toenails, and duplicate-plate food collections for selenium analysis. About half of the 142 free-living subjects had selenium intakes greater than 2.54 mumol/d (200 micrograms/d) (range 0.86-9.20 mumol/d, or 68-724 micrograms/d). Physical findings characteristic of selenium toxicity were not present nor were clinically significant changes in laboratory tests or frequency of symptoms related to selenium in the blood, toenails, or diet. We found no evidence of toxicity from selenium in subjects whose intake was as high as 9.20 mumol/d (724 micrograms/d).     

Selenium concentration in maternal and umbilical cord blood, placenta and amniotic membranes

The selenium concentration of maternal and umbilical cord whole blood was determined by atomic absorption spectrophotometry in 21 parturients at term. Six placental and amniotic membrane tissue specimens were also investigated. The mean selenium concentrations in the maternal (0.73 +/- 0.15 mumol/l) and umbilical cord blood (0.77 +/- 0.18 mumol/l) were similar and without significant correlation. Placental (2.24 +/- 0.20 mumol/kg wet weight) and amniotic membrane tissue specimens (2.32 +/- 0.54 mumol/kg wet weight) also contained similar concentrations of selenium which were about 3 times higher than those in the maternal and umbilical cord blood. Low whole blood selenium concentration in Finnish parturients may be a sign of deficient nutritional intake of selenium during pregnancy. The relatively high concentration of selenium in the placenta and amniotic membranes on the other hand suggest that metabolically active organs are being provided primarily with this essential trace element.     

Malnutrition in tubefed nursing home patients with pressure sores.

This study compares the nutritional status and dietary intake of 14 tubefed nursing home patients with pressure sores (age: 70 +/- 5 years, mean +/- SEM) to 12 tubefed patient-controls without sores (age: 60 +/- 7 years). Patients tended to have higher calorie intake (32 +/- 3 kcal/kg) than patient-controls (26 +/- 2 kcal/kg, p = 0.11). Protein intake was significantly higher in patients (1.4 +/- 0.2 g/kg) than patient-controls (0.9 +/- 0.1 g of protein per kg, p less than 0.05). Despite increased calorie and protein intake, biochemical measures of nutritional status were worse in the patients. Serum albumin was lower in patients (33 +/- 1 g/L) than in patient-controls (37 +/- 1 g/L, p less than 0.05) as was level of hemoglobin (patients: 117 +/- 5; patient-controls: 132 +/- 5 g/L, p less than 0.05). Patients with stage IV (severe) sores had lower serum cholesterol levels (3.46 +/- 0.31 mmol/L, n = 5) than patients with stage II/III (milder) sores (4.58 +/- 0.23 mmol/L, n = 9, p less than 0.05). Plasma zinc was low in both patients (11.2 +/- 0.6 mumol/L) and patient-controls (11.5 +/- 0.7 mumol/L, p = NS). Pressure sore surface area was positively correlated with calorie intake per kilogram of body weight (r = +0.59, p less than 0.04) and negatively correlated with body mass index (r = -0.70, p less than 0.03), hemoglobin (r = -0.55, p less than 0.07) and serum cholesterol (r = -0.57, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

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

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

Trace element nutrition status and dietary intake of children with phenylketonuria

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

Maternal and fetal selenium concentrations and their interrelationships in dairy cattle

Paired dam-fetus serum, whole blood and liver samples were collected from 101 pregnant dairy cattle at slaughter to establish mean values for fetal tissue selenium concentration and to determine relationships between maternal and fetal selenium status. Samples were assayed for selenium concentration in serum, whole blood and liver and for whole blood glutathione peroxidase (GSH-Px) activity. Fetal age was estimated from fetal crown-to-rump length. Mean fetal liver (2.14 micrograms/g dry wt) and serum (21.4 ng/ml) selenium concentrations and whole blood GSH-Px activity (21.6 mu/ml) differed (P less than 0.0001, 0.0001 and 0.01, respectively) from corresponding maternal values (0.95 micrograms/g liver dry wt; 44.0 ng/ml; 16.7 mu/ml, respectively), while no differences were found between whole blood or erythrocyte selenium concentrations. Fetal liver selenium concentration was greater than corresponding maternal liver selenium in 99% (96/97) of the dam-fetal pairs, suggesting efficient placental transfer and fetal concentrating ability. Maternal liver selenium concentration was most highly correlated to all fetal tissue selenium concentrations and used to develop prediction models. These data suggest that selenium efficiently passes the placenta, and based on published values of adequate adult liver selenium concentrations and maternal-fetal relationships, we suggest an adequate liver selenium concentration in the bovine fetus to be greater than 2.2 micrograms/g liver dry wt, and in whole blood, greater than 120 ng/ml.     

Selenium status and cardiovascular risk factors in healthy Dutch subjects

To provide further insight into the possible role of selenium in cardiovascular disease, we examined the relationship between cardiovascular risk factors, some nutritional parameters, and short- and long-term selenium status. A total of 82 healthy Dutch volunteers, 59 men and 23 women, aged 40-75 years, were studied. Means and standard deviations of selenium parameters were: plasma selenium 106.4 +/- 23.7 micrograms/L, erythrocyte selenium 0.59 +/- 0.19 microgram/g Hb, toenail selenium 0.78 +/- 0.17 ppm, and erythrocyte glutathione peroxidase activity 28.0 +/- 8.1 U/g Hb. No association was found between selenium status and gender, age, serum total-, LDL-, and HDL-cholesterol, systolic and diastolic blood pressure, alcohol intake, and body mass index. A significantly lower plasma selenium level was observed among smokers compared to nonsmokers (101.0 micrograms/L, SE = 3.9 vs 112.0 micrograms/L, SE = 3.6, p = 0.04). A significant negative association was found between erythrocyte selenium and serum levels of vitamin A and ferritin. No relevant relationship was observed between selenium status and serum fatty acid composition, vitamin E, vitamin B6, and iron. Apart from an association between smoking and short-term selenium status, we found no indications that a possible effect of selenium on cardiovascular disease may operate through the known risk factors.     

Low serum selenium and glutathione peroxidase activity in patients receiving short-term total parenteral nutrition

Selenium status was determined in 15 consecutive postoperative patients receiving short-term total parenteral nutrition (TPN) using both serum selenium concentration and glutathione peroxidase (GSH-Px) activity as an indicator of body selenium status. The serum selenium concentration was significantly (p less than 0.001) lower in TPN patients (0.52 +/- 0.16 mumol/l, mean +/- SD) than in age- and sex-matched controls (1.08 +/- 0.17 mumol/l). Serum selenium in TPN patients ranged from 0.28 to 0.79 mumol/l and was associated with the duration of TPN. The lowest selenium values was found in patients who had received TPN over 3 weeks (0.35 +/- 0.06 mumol/l) as compared to patients receiving TPN for 1-3 weeks (0.61 +/- 0.13 mumol/l; p less than 0.01). Serum GSH-Px activity in TPN patients was also low (116 +/- 21 U/l) and ranged from 75 to 159 U/l. A significant positive correlation was found between serum selenium and GSH-Px activity (r = 0.520; p less than 0.05) whereas serum selenium and GSH-Px activity did not correlate significantly with liver function tests and body mass index. This study suggests that also short-term TPN patients may be at risk of selenium deficiency.     

Selenium metabolism and platelet glutathione peroxidase activity in healthy Finnish men: effects of selenium yeast, selenite, and selenate

The mean dietary selenium intake in Finland increased from 40 to 100 micrograms/d in 1987 because of the addition in 1985 of selenium to fertilizers. A selenium-supplementation study was performed in 1987 on the same men as were followed in a 1981 study that had a similar design (200 micrograms Se/d). Selenite and selenate, but not selenium yeast increased platelet glutathione peroxidase (GSHPx) activity by 30% compared with placebo, much less than the 70% found in the previous study. Selenium yeast and selenite increased plasma selenium after 11 wk from 1.39 mumol/L to peak values of 2.15 and 1.58 mumol/L, respectively. Only yeast selenium was incorporated into red cells. From a regression plot based on present and literature data, it was estimated that the plasma selenium concentration needed to achieve maximal platelet GSHPx activity was 1.25-1.45 mumol/L. At the present selenium intake in Finland, 100 micrograms/d, GSHPx activity is saturated in plasma and red cells and almost saturated in platelets.     

Beta-carotene uptake and tissue distribution in ferrets (Mustela putorius furo).

Ferrets accumulate beta-carotene in liver and adipose tissue after chronic feeding. This study was designed to further evaluate the time course of uptake and depletion of beta-carotene in ferret serum and tissues. Male ferrets (n = 15; 1000-1200 g) were given a single dose of beta-carotene (10 mg/kg body wt) with a meal. Animals were killed at various time points over an 11-d period. Blood and tissue samples were extracted and analyzed for beta-carotene by HPLC. Peak serum beta-carotene levels (0.68 +/- 0.18 mumol/L) were observed 8 h after the test meal. beta-Carotene was essentially cleared from the blood by 76 h. Peak beta-carotene concentrations (nmol/g) were observed between 8 and 16 h after ingestion for liver (1.20 +/- 0.04), lung (0.042 +/- 0.012), kidney (0.090 +/- 0.015) and spleen (0.076 +/- 0.012). Ferret liver also seemed to contain a variety of other polar and nonpolar carotenoids. Ferrets were shown to absorb beta-carotene from a meal and have a consistent serum response pattern. Absorbed beta-carotene is differentially distributed in a variety of tissues. The ferret seems to be a useful model for the study of beta-carotene absorption and metabolism.     

Primary school children from northeast Thailand are not at risk of selenium deficiency

Selenium has important roles as an antioxidant, in thyroid hormone metabolism, redox reactions, reproduction and immune function, but information on the selenium status of Thai children is limited. We have assessed the selenium status of 515 northeast Thai children (259 males; 256 females) aged 6 to 13 years from 10 rural schools in Ubon Ratchthani province. Serum selenium (n=515) was analyzed by Graphite Furnace Atomic Absorption Spectrophotometry and dietary selenium intake by Hydride Generation Absorption Spectrophotometry from one-day duplicate diet composites, from 80 (40 females; 40 males) randomly selected children. Inter-relationships between serum selenium and selenium intakes, and other biochemical micronutrient indices were also examined. Mean (SD) serum selenium was 1.46 (0.24) micro mol/L. Concentrations were not affected by infection or haemoglobinopathies, but were dependent on school (P< 0.001), sex (P=0.038), and age group (P=0.003), with serum zinc as a significant covariate. None of the children had serum selenium concentrations indicative of clinical selenium deficiency (i.e. <0.1 micro mol/L). Significant correlations existed between serum selenium and serum zinc (r= 0.216; P < 0.001), serum retinol (r = 0.273; P < 0.001), urinary iodine (r = -0.110; P = 0.014), haemoglobin (r = 0.298; P <0.001), and haematocrit (r = 0.303; P< 0.001). Mean (SD) dietary selenium intake was 46 (22) micro g/d. Children with low serum selenium concentrations had a lower mean selenium intake than those with high serum selenium concentrations (38 +/- 17 vs.51 +/- 24 micro g/d; P< 0.010). In conclusion, there appears to be no risk of selenium deficiency among these northeast Thai children.     

Lead exposure in highway toll-booth workers

Biomarkers of lead exposure (blood lead, BPb) and effect (erythrocyte protoporhyrin, EP, and activity of delta-aminolevulinic acid dehydratase, ALAD) were measured in 68 male toll-booth operators (aged 22-60 years) on the Zagreb-Karlovac motorway. Average values (arithmetic mean +/- standard deviation) were: 61.8 +/- 29.3 micrograms/L for BPb, 0.70 +/- 0.20 mumol/L erythrocytes for EP, and 50.6 +/- 9.8 U/L erythrocytes for ALAD. All were within the normal range determined for general population (BPb < 150 micrograms/L, EP < 1.62 mumol/L erythrocytes, and ALAD > 35 U/L erythrocytes). A significant positive correlation was found between BPb and EP (r = 0.367, P < 0.01) and an inverse correlation between BPb and ALAD (r = -0.271, P < 0.05) and for EP and ALAD (r = -0.381, P < 0.01). Significant correlations were found between BPb or ALAD and smoking index (r = 0.486, P < 0.01, and r = -0.322, P < 0.01, respectively), whereas BPb also significantly correlated with blood gamma-glutamyl transferase (GGT) activity, which may indicate hepatotoxic effect of alcohol consumption (r = 0.334, P < 0.01). Among standard spirometric tests, BPb inversely correlated with FEV1 (r = -0.251, P < 0.05) and Tiffenau index (r = -0.280, P < 0.05), whereas ALAD positively correlated with FEF75-85 (r = 0.261, P < 0.05) and Tiffenau index (r = 0.314, P < 0.01). Among standard hematologic tests, BPb positively correlated with MCV (r = 0.282, P < 0.05), EP inversely correlated with erythrocyte count (r = -0.253, P < 0.05), and ALAD positively correlated with MCHC (r = 0.306, P < 0.05) and inversely with MCV (r = -0.250, P < 0.05). Although PbB values in these workers are within occupational exposure limits, they are higher than in corresponding occupations in developed countries. This may be explained by greater exposure to lead in ambient air, tobacco (through mainstream and sidestream smoking) and alcohol in this population.     

Predictors of selenium concentration in human toenails

To assess the validity of the selenium concentration in human toenails as a measure of selenium intake and to determine other correlates of toenail selenium level, the authors examined the predictors of toenail selenium within two subgroups of a large cohort study of US women. Mean toenail selenium was higher among 38 consumers of selenium supplements (0.904 micrograms/g, standard deviation (SD) 0.217) than among 96 nonusers (0.748 micrograms/g, SD 0.149; p less than 0.001), and a dose-response relation was observed among supplement users (Spearman's r = 0.32; p = 0.05). In a second subgroup of 677 women, selenium supplement use was also associated with higher mean toenail selenium (0.906 micrograms/g, SD 0.214, among 18 users and 0.801 micrograms/g, SD 0.148, among 659 nonusers; p = 0.02), and the dose-response relation was also significant (Spearman's r = 0.50; p = 0.03). The geographic variation in toenail selenium levels was consistent with the geographic distribution of selenium in forage crops. Toenail selenium declined with age and was significantly reduced among cigarette smokers (mean = 0.746, SD 0.124, among 146 current smokers and mean = 0.817, SD 0.159, among 311 never smokers; p less than 0.001) but was not materially affected by alcohol consumption. A dietary selenium score calculated from a food frequency questionnaire failed to predict toenail selenium level, demonstrating the suspected inability of diet questionnaires to measure individual selenium intake because of the highly variable selenium composition of different samples of the same food.(ABSTRACT TRUNCATED AT 250 WORDS)     

Decreased serum selenium in alcoholics as related to liver structure and function

Serum selenium was evaluated in relation to hepatic structure and function in 46 alcoholics with diagnostic liver biopsy classified into 4 groups by hepatic histology. Their serum selenium concentration varied from 12 to 88 micrograms/l and was lower (p less than 0.001) in all groups of alcoholics, ie patients with normal liver (53.0 +/- 20.7 micrograms/l, mean +/- SD), fatty liver (55.8 +/- 21.2 micrograms/l), alcoholic hepatitis (46.0 +/- 14.1 micrograms/l), and cirrhosis (41.1 +/- 12.8 micrograms/l), than in 25 healthy controls (88.7 +/- 11.0 micrograms/l). Serum selenium level was related to the severity of liver disease, and most reduced in subjects with decompensated alcoholic cirrhosis. Their serum selenium level (29.2 +/- 13.7 micrograms/l) was below (p less than 0.05) that obtained in alcoholics with normal liver and fatty liver respectively. Both inadequate dietary selenium intake and alcohol-induced changes in hepatic structure and function may have contributed to the decrease of serum selenium in the subjects studied.     

Blood lead concentration, renal function, and blood pressure in London civil servants.

Blood lead concentration was measured in 398 male and 133 female London civil servants not subject to industrial exposure to heavy metals. The relation between blood lead and serum creatinine concentrations and blood pressure were examined. Blood lead concentration ranged from 0.20 to 1.70 mumol/l with a geometric mean concentrations of 0.58 mumol/l in men and 0.46 mumol/l in women (p less than 0.001). In women blood lead concentration increased with age (r = +0.27; p = 0.002). In the two sexes blood lead concentration was positively correlated with the number of cigarettes smoked a day (men r = +0.17 and women r = +0.22; p less than or equal to 0.01), with the reported number of alcoholic beverages consumed a day (men r = +0.34 and women r = 0.23; p less than 0.01), and with serum gamma-glutamyltranspeptidase (men r = +0.23 and women r = +0.14; for men p less than 0.01). Blood lead concentration was not correlated with body weight, body mass index, and employment grade. In men 14% of the variance of blood lead concentration was explained by the significant and independent contributions of smoking and alcohol intake and in women 16% by age, smoking, and alcohol consumption. In men serum creatinine concentration tended to rise by 0.6 mumol/l (95% confidence interval from -0.2 to +1.36 mumol/l) for each 25% increment in blood lead concentration. In men and women the correlations between blood lead concentration and systolic and diastolic blood did not approach statistical significance. In conclusion, in subjects not exposed to heavy metals at work gender, age, smoking, and alcohol intake are determinants of blood lead concentration. At a low level of exposure, lead accumulation may slightly impair renal function, whereas blood pressure does not seem to be importantly influenced. Alternatively, a slight impairment of renal function may give rise to an increase in blood lead concentration.     

Blood lead concentration, renal function, and blood pressure in London civil servants

Blood lead concentration was measured in 398 male and 133 female London civil servants not subject to industrial exposure to heavy metals. The relation between blood lead and serum creatinine concentrations and blood pressure were examined. Blood lead concentration ranged from 0.20 to 1.70 mumol/l with a geometric mean concentrations of 0.58 mumol/l in men and 0.46 mumol/l in women (p less than 0.001). In women blood lead concentration increased with age (r = +0.27; p = 0.002). In the two sexes blood lead concentration was positively correlated with the number of cigarettes smoked a day (men r = +0.17 and women r = +0.22; p less than or equal to 0.01), with the reported number of alcoholic beverages consumed a day (men r = +0.34 and women r = 0.23; p less than 0.01), and with serum gamma-glutamyltranspeptidase (men r = +0.23 and women r = +0.14; for men p less than 0.01). Blood lead concentration was not correlated with body weight, body mass index, and employment grade. In men 14% of the variance of blood lead concentration was explained by the significant and independent contributions of smoking and alcohol intake and in women 16% by age, smoking, and alcohol consumption. In men serum creatinine concentration tended to rise by 0.6 mumol/l (95% confidence interval from -0.2 to +1.36 mumol/l) for each 25% increment in blood lead concentration. In men and women the correlations between blood lead concentration and systolic and diastolic blood did not approach statistical significance. In conclusion, in subjects not exposed to heavy metals at work gender, age, smoking, and alcohol intake are determinants of blood lead concentration. At a low level of exposure, lead accumulation may slightly impair renal function, whereas blood pressure does not seem to be importantly influenced. Alternatively, a slight impairment of renal function may give rise to an increase in blood lead concentration.     

Effect of food restriction on tissue carnitine concentration in rats

The effect of feeding different amounts of a standard laboratory pellet diet on tissue carnitine concentration was studied in four groups of rats. Group I was fed ad libitum, whereas food intake was restricted to 25, 20, and 15g protein/kg body weight/day in group II, III, and IV, respectively. The intake of food, protein, energy and carnitine was constant and adjusted to actual body weight in groups 2-4. Six weeks food restriction had no effect on muscle carnitine. Restricted diet caused lowered concentrations of carnitine in serum (group I, fed ad libitum, total 95.0 +/- 13.8, free 80.2 +/- 2.7; group II total 78.4 +/- 8.4, free 56.9 +/- 4.7; group III total 81.7 +/- 8.8, free 66.0 +/- 8.8; and group IV total 73.8 +/- 8.7, free 59.5 +/- 7.6 mumol/l) and urinary carnitine excretion (group I, total 7.1 +/- 3.3, free 6.3 +/- 3.1; group II, total 2.5 +/- 0.7, free 2.2 +/- 0.7; group III, total 1.9 +/- 0.8, free 1.6 +/- 0.8; and group IV, total 1.3 +/- 0.4 free 1.1 +/- 0.3 mumol/day). In contrast, the liver carnitine tended to increase when dietary intake was reduced (group I total 1.1 +/- 0.1, free 1.0 +/- 0.1; group II total 1.5 +/- 0.2, free 1.4 +/- 0.2; group III total 1.3 +/- 0.1, free 1.1 +/- 0.1; and group IV total 1.5 +/- 0.2, free 1.4 +/- 0.2 mumol/g dry wt). The highest liver carnitine concentrations were observed during the lowest dietary intake when also the serum and urine carnitine were lowest. We conclude that the amount of food intake has a direct impact on carnitine concentrations in the liver, serum, and urine while muscle carnitine concentration remains relatively stable despite wide variations in food intake.     

Projected uptake and toxicity of selenium compounds from the environment

Industrial workers and members of the general public may be exposed to selenium by inhalation of selenium in the workplace or atmosphere or by ingestion of selenium in food. A model has been developed to evaluate the potential uptake of selenium in body tissues by these two exposure routes. Rates were estimated for transport of selenium between five compartments including lung, gastrointestinal tract, blood, liver and other tissues. Results of model simulations were compared to published tissue distribution information obtained from single inhalation exposures of rats and dogs to radiolabeled selenium compounds at concentrations from 20 mg/m3 to 20 micrograms/m3 with initial body burdens of selenium ranging from 28 to 0.09 micrograms Se/kg body wt. The model was then modified to predict equilibrium organ concentrations of selenium in people after continual exposure to selenium in the air or in the diet. Daily intake levels of 100 micrograms/day and a fractional absorption value of 0.8 were used. With an air concentration of 1 ng Se/m3, model predictions indicated that most of the total body selenium in people is likely to come from their diet because selenium in the urban atmosphere contributes a very small part of the total body selenium. However, continual inhalation of selenium at the threshold limit value (TLV; 200 micrograms/m3) could contribute significantly to the total body burden of selenium. Levels of selenium predicted in lung, liver, and blood after inhalation of selenium at the TLV were 22,000, 1200, and 440 ng Se/g tissue. Predicted lung concentrations were near those that produced toxic effects in animals after ingestion of Se.     

Decrease of mucosal glutamine concentration in the nutritionally depleted patient

A diminished glutamine delivery by peripheral tissues is suggested to play an important role in the etiology of postoperative complications of nutritionally depleted patients. Decreased glutamine supply to the gut mucosa in these nutritionally depleted patients may have important consequences for the integrity of the gut mucosa barrier. To evaluate whether glutamine concentration in the gut mucosa of depleted patients is altered, patients with either a fat-free mass index below 90% or percentage ideal body weight below 90% as a result of weight loss were studied. 22 patients admitted to the University Hospital Maastricht and 14 controls were studied. After an overnight fast, venous blood was sampled and duodenal biopsies were obtained by endoscopy. Plasma and tissue amino acids were measured. Fat-free mass was determined by bioelectrical impedance measurement. In 10 depleted patients glutamine concentration in the duodenal mucosa was 2883 +/- 250 mumol/kg dry weight. Concentration of alanine was 2570 +/- 263 mumol/kg dry weight. In the non-depleted patients glutamine and alanine concentrations were respectively 3463 +/- 171 mumol/kg dry weight and 3540 +/- 315 mumol/kg dry weight. Concentrations in controls were 3296 +/- 176 mumol/kg dry weight for glutamine and 3682 +/- 372 mumol/kg dry weight for alanine. Concentrations for alanine and glutamine were significantly lower in depleted patients compared to non-depleted patients (p < 0.05). Also, alanine and glutamine concentrations were significantly correlated with percentage ideal body weight (r=0.43, p < 0.005 for glutamine and r=0.62, p < 0.001 for alanine) and fat-free mass index (r=0.42, p < 0.05 for glutamine and r=0.48, p < 0.01 for alanine) This study suggests that in patients depletion appears to be related to decreased plasma and mucosa glutamine and alanine concentrations.     

Nutritional assessment of vitamin E in malnourished patients with AIDS

Malnourished patients with acquired immunodeficiency syndrome (AIDS) may have low serum levels and reduced intake of alpha-tocopherol, mainly in the presence of acute-phase response. The aims of this study were to compare intake and serum levels of alpha-tocopherol between malnourished (MN) and non-malnourished (NMN) AIDS patients and to correlate alpha-tocopherol intake and serum levels. Undernutrition was defined as having a body mass index lower than 18. 5 kg/m(2) or a height-creatinine index lower than 70%. A semiquantitative food frequency questionnaire assessed alpha-tocopherol intake. High-performance liquid chromatography determined vitamin serum levels. The patients were divided into MN (n = 14) and NMN (n = 15) groups. There were no statistical differences in relation to clinical findings between MN and NMN, respectively, including moniliasis (7/14 versus 4/15), neurocryptoccocosis and neurotoxoplasmosis (6/14 versus 6/15), pulmonary tuberculosis (4/14 versus 2/15), and fever (1/14 versus 3/15). MN and NMN groups had similar peripheral blood CD(4) levels (111.4+/-87.1 versus 124.4+/-90.9 cells/mm(3)), and both groups had similar and adequate alpha-tocopherol intake (MN = 50.0+/-11.0 versus NMN = 47.2+/-16.5 mg) and serum levels (MN = 17.8+/-7.2 versus NMN = 19.8+/-6.3 micromol/L). Vitamin E intake and serum levels did not show a significant correlation (r = -0.22, P 0.05). Protein-energy nutrition status and acute-phase response were not factors determining vitamin status among AIDS patients.