Rye bread intake improves oxidation resistance of LDL in healthy humans.

BACKGROUND: Oxidatively modified LDL particles contribute to atherogenic development and therefore dietary interventions for promoting oxidation resistance of LDL are of interest. The capacity of LDL to resist oxidation can be determined ex vivo by exposing isolated LDL particles to copper ions and measuring the formation of conjugated dienes by spectrophotometry. OBJECTIVE: The aim of this trial was to determine the effect of none versus high intake of rye bread on the oxidation resistance of LDL in healthy humans while otherwise on habitual diet. DESIGN: Sixty-three healthy subjects excluded rye products for one week (baseline), followed by a stepwise addition of rye bread from 99 g/d during the first two weeks to 198 g/d during the following two weeks. Additionally plant sterols were incorporated into the rye bread for half of the subjects to study cholesterol-lowering. The resistance of LDL against copper-induced oxidation was determined at baseline and at the end of the rye-period by monitoring formation of conjugated dienes. RESULTS: We observed a significant increase in the oxidation resistance of LDL, determined as a prolongation of the lag time (P < 0.001) and decrease in the slope of the propagation phase (P = 0.048) from baseline to the end of the rye-period without changes in vitamin E concentration. We observed no significant differences in the oxidation resistance of LDL between subjects who did or did not receive plant sterols. CONCLUSIONS: Rye bread intake improved significantly the oxidation resistance of LDL. Further studies are needed to clarify the protective mechanism(s).

Selenium status and blood lipids: the cardiovascular risk in Young Finns study.

BACKGROUND: Concern has been recently raised about possible adverse cardio-metabolic effects of high selenium status, such as increased risks of diabetes and hyperlipidaemia. However, most of the evidence comes from selenium-replete populations such as that of the United States. OBJECTIVES: To examine cross-sectional and longitudinal associations of serum selenium with cardiovascular risk factors in Finland where selenium levels were amongst the lowest in the world until the early 1980s before the implementation of a nationwide selenium fertilization programme. METHODS: Serum selenium was measured in 1235 young Finns aged 3-18 years at baseline in 1980 (prefertilization) and in a subgroup (N = 262) at the 6-year follow-up (1986, postfertilization). During the 27-year follow-up, serum lipids, blood pressure, body mass index and smoking were assessed five times (1980, 1983, 1986, 2001 and 2007). RESULTS: Mean (±SD) serum selenium concentrations were 74.3 ± 14.0 ng mL(-1) in 1980 and 106.6 ± 12.5 ng mL(-1) in 1986 (average increase 32.3 ng mL(-1); 95% CI: 30.3 to 34.3, P < 0.0001). In univariate and multivariable cross-sectional models in 1980 and 1986, increased serum selenium levels were consistently associated with increased total, HDL and Low-density lipoprotein (LDL) cholesterol. However, the average longitudinal changes in lipids were -0.20 mmol L(-1) (95% CI: -0.30 to -0.10, P < 0.0001) for total cholesterol, 0.06 mmol L(-1) (95% CI: 0.03 to 0.10, P < 0.0001) for HDL cholesterol, and -0.23 mmol L(-1) (95% CI: -0.31 to -0.14, P < 0.0001) for LDL cholesterol. Selenium measured in 1986 was not associated with lipids assessed in 2001 and 2007. CONCLUSIONS: Cross-sectional findings from the Young Finns study corroborate positive associations of selenium status with serum lipids. However, longitudinal evidence does not support the causality of this link.

Long-term effect of betaine on risk factors associated with the metabolic syndrome in healthy subjects.

BACKGROUND/OBJECTIVES: To examine the effects of betaine on serum lipid profile, plasma homocysteine concentration and hemostatic factors in healthy subjects. SUBJECTS/METHODS: Altogether, 63 volunteers (27 ± 8 years, body mass index 22.6 ± 2.4 kg/m(2)) participated in a placebo-controlled, randomized, parallel double-blinded study. The intervention lasted for 6 months during which the subjects consumed mineral water 500 ml/day with (betaine group, n = 32) or without (control group, n = 31) a 4-g betaine supplementation. RESULTS: There was a significant interaction of time and group (general linear model) in serum total and low-density lipoprotein (LDL)-cholesterol concentrations and total-to-high-density lipoprotein (HDL)-cholesterol ratio without a significant difference between or within the groups. Concentrations of serum HDL-cholesterol, triglycerides or oxidized LDL did not change during the study. Plasma homocysteine concentration did not change in either of the groups. Plasma plasminogen activator inhibitor 1 concentration increased in the betaine group (P = 0.028) and decreased in the control group (P = 0.006). There was a significant interaction of time and group (general linear model) in plasma fibrinogen and blood hemoglobin concentration without a significant difference between or within the groups. There were no changes in parameters regarding the function of the liver or kidney. CONCLUSIONS: Betaine had no effect on serum lipid profile in long term in young healthy subjects. The lowering effect on plasma homocysteine concentration was weak.

Serum fatty acids and risk of advanced beta-cell autoimmunity: a nested case-control study among children with HLA-conferred susceptibility to type I diabetes.

BACKGROUND/OBJECTIVES: N-3 (omega-3) fatty acids have been reported to decrease the risk for development of beta-cell autoimmunity and clinical type I diabetes. We set out to examine whether different serum fatty acids are associated with the development of advanced beta-cell autoimmunity in children carrying human leukocyte antigen DQ beta-1 (HLA-DQB1)-conferred susceptibility to type I diabetes. SUBJECTS/METHODS: Within a cohort, serum total fatty acid composition of 108 children with advanced beta-cell autoimmunity and of 216 matched persistently autoantibody-negative controls was analyzed using gas chromatography. Non-fasting serum samples were obtained annually at the ages of 1-6 years. Conditional logistic regression was applied to analyze the associations between advanced beta-cell autoimmunity and serum fatty acids. RESULTS: The serum fatty acid profile of myristic acid (odds ratio (OR) 1.48, 95% confidence interval (CI) 1.09-2.00, P=0.011), pentadecanoic acid (OR 1.65, 95% CI 1.19-2.28, P=0.003), palmitoleic acid isomers 16:1 n-7 (omega-7) (OR 1.41, 95% CI 1.03-1.92, P=0.030) and 16:1 n-9 (omega-9) (OR 1.45, 95% CI 1.05-2.01, P=0.026) and conjugated linoleic acid (OR 1.67, 95% CI 1.16-2.41, P=0.006) closest to the time of the appearance of multiple autoantibodies were positively associated with the risk of advanced beta-cell autoimmunity after adjustment for potential confounding factors. Serum linoleic acid showed inverse, marginal association with the end point. CONCLUSIONS: Serum biomarkers of milk and ruminant meat fat consumption are directly associated and linoleic acid is inversely associated with advanced beta-cell autoimmunity in children with HLA-conferred susceptibility to type I diabetes.

Folate intake, plasma folate and homocysteine status in a random Finnish population.

OBJECTIVE: To assess the folate status of Finnish adults using plasma folate and homocysteine as biomarkers and to evaluate dietary and supplementary folate intakes. MATERIALS AND METHODS: Plasma folate, vitamin B(12) and total homocysteine (tHcy) were determined in a random sample of 643 subjects aged 25-74 y living in the Helsinki area. The methylenetetrahydrofolate reductase (MTHFR)-genotypes were analyzed from a subsample (n=394). Dietary intake data by 24 h recall and use of vitamin supplements were collected. RESULTS: Plasma folate was normal (>/=5 nmol/l) in 99% of subjects and optimal (>/=8 nmol/l) in terms of a minimum tHcy in 90%. Mean plasma folate of non-supplement users was 13.7 and 12.9 nmol/l and tHcy 11.3 and 9.2 micro mol/l for men and women, respectively. Elevated tHcy (>14 micro mol/l) was found in 11% of subjects. Homozygote frequency for MTHFR genotype TT was 5.0% and their plasma tHcy was 14.8 micro mol/l compared to the mean of the other subjects, 10.5 micro mol/l, P<0.05. The mean dietary folate intake was 241 micro g/day (29 micro g/MJ of energy) for men and 205 micro g/day (33 micro g/MJ) for women, respectively. The main dietary sources of folate were vegetables 12%, wholemeal ryebread 11%, fruits 10%, and potato 10%. Regular supplement users (n=97) received on average 207 micro g folic acid per day from supplements. CONCLUSIONS: The folate status of Finnish adults seems to be adequate according to energy adjusted folate intake, plasma folate and homocysteine. The MTHFR homozygote frequency was low compared to other countries. Regular use of supplementary folic acid less than 300 micro g increased plasma folate, but supplemental folic acid over 300 micro g was required to lower tHcy values significantly.

Selenium supplementation of children in a selenium-deficient area in China: blood selenium levels and glutathione peroxidase activities.

Keshan disease is a cardiomyopathy restricted to the endemic areas of China and seen in residents having an extremely low selenium (Se) status. Prophylactic administration of sodium selenite has been shown to decrease significantly the incidence of acute and subacute cases. The aim offthe study was to assess the relative bioavailability of selenite versus organic Se-yeast in a Se-deficient area in China with a randomized double-blind double-dummy design. Healthy children (n=30) between 14 and 16 yr of age were randomized into three equal groups receiving either 200 microg/d selenite Se or 200 microg/d Se-yeast or placebo for 12 wk. Blood was drawn at baseline, 4, 8, and 12 wk and 4 wk postsupplementation. The plasma Se concentration (mean +/- SD) was 0.16+/-0.03 micromol/L at baseline. Selenite and Se-yeast supplementation increased plasma Se to plateau values, 1.0+/-0.2 and 1.3+/-0.2 micromol/L, respectively. In red cells, Se-yeast increased the selenium level sixfold and selenite threefold compared to placebo. The relative bioavailability of Se-yeast versus selenite measured as glutathione peroxidase (GSHPx) activity was similar in plasma, red blood cells, and platelets. GSHPx activity reached maximal levels in plasma and platelets of 300% and 200%, respectively, after 8 wk compared to the placebo group, but continued to increase in red cells for 16 wk. Our study showed that although both forms of Se were equally effective in raising GSHPx activity, Se-yeast provided a longer lasting body pool of Se. Se-yeast may be a better alternative to selenite in the prophylaxis of Keshan disease with respect to building up of body stores.

Serum selenium, serum alpha-tocopherol, and the risk of rheumatoid arthritis.

Antioxidant micronutrients have been hypothesized to provide protection against rheumatoid arthritis. We investigated serum selenium and serum alpha-tocopherol for their prediction of subsequent development of rheumatoid arthritis in a case-control study nested within a Finnish cohort of 18,709 adult men and women who had neither arthritis nor a history of it at the baseline examination in 1973-1978; by late 1989, 122 had developed rheumatoid arthritis. Of the incident cases, 34 were rheumatoid factor-negative. Three controls per each incident case were individually matched for sex, age, and municipality. Serum selenium and alpha-tocopherol concentrations were measured from stored serum samples collected at baseline. Serum selenium was inversely related to subsequent occurrence of rheumatoid factor-negative but not rheumatoid factor-positive rheumatoid arthritis. The relative risks, adjusted for smoking and serum total cholesterol, for the highest relative to the lowest tertile of serum selenium, were 0.16 [95% confidence interval (CI) = 0.04-0.69] for rheumatoid factor-negative and 0.96 (CI = 0.49-1.90) for rheumatoid factor-positive rheumatoid arthritis. During the first 10 years of follow-up, the relative risk for rheumatoid arthritis for the highest compared with the lowest tertile of serum alpha-tocopherol was 0.44 (CI = 0.19-0.99). No association was found for longer follow-up periods. Low selenium status may be a risk factor for rheumatoid factor-negative rheumatoid arthritis, and low alpha-tocopherol status may be a risk factor for rheumatoid arthritis independently of rheumatoid factor status.

Toenail selenium and breast cancer-a case-control study in Finland.

OBJECTIVE: Low levels of selenium have been associated with a higher risk of cardiovascular diseases and cancer in humans. Since 1984, selenium supplementation through fertilizers has been employed in Finland to increase the very low concentration of selenium in the nation's food supply. As a result, the selenium concentration of Finnish foods became one of the highest in Europe. A decade after selenium supplementation began, the association between toenail selenium and the risk of breast cancer was examined. DESIGN: Case-control study. SETTING: Eastern Finland. SUBJECTS: 289 pre- and postmenopausal breast cancer cases and 433 community controls. The diagnosis was unknown at the time the toenail samples were collected. RESULTS: The mean toenail selenium concentration was 0.80 mg/kg in premenopausal cases and 0.84 mg/kg in premenopausal controls: and 0. 77 mg/kg in postmenopausal cases and 0.80 mg/kg in postmenopausal controls. The odds ratio (OR) comparing the highest with the lowest quintiles of toenail selenium concentration was 1.1 (95% CI 0.4-3.2) in premenopausal women and 0.7 (95% CI 0.3-1.5) in postmenopausal women. The intake of retinol, beta-carotene, vitamin E and vitamin C did not change the association between toenail selenium and breast cancer. CONCLUSIONS: A decade after selenium supplementation, selenium seems not to be an important factor in the etiology of breast cancer, neither in premenopausal nor postmenopausal women. SPONSORSHIP: This work was supported by the EVO funds from the Kuopio University Hospital and by research grants from the Academy of Finland, Yrjö Jahnsson Foundation and Juho Vainio Foundation. European Journal of Clinical Nutrition (2000) 54, 98-103

Selenium depletion in hemodialysis patients treated with polysulfone membranes.

BACKGROUND/AIMS: Epidemiological, animal and human studies have indicated that selenium deficiency is a risk factor for death from malignant diseases. The mechanisms that could modify selenium status may, therefore, be of particular interest in hemodialysis patients, considering their high cancer mortality rates. We aimed at evaluating the effect of hemodialysis with polysulfone membranes on selenium status. METHODS: Twenty- eight chronically dialyzed patients and 32 age-matched healthy controls were enrolled in the study. Serum and dialysis fluid selenium concentrations, serum total protein, and hemoglobin concentrations and serum glutathione peroxidase activity were determined before and after the hemodialysis procedure. RESULTS: The (mean +/- SD) serum selenium and total protein concentrations and glutathione peroxidase activities were significantly (p < 0.05) higher in healthy controls (75.9 +/- 8.3 microg/l, 78 +/- 6 g/l, and 23.8 +/- 4.8 mU/20 microl, respectively) than in the patients. There was no significant difference between serum selenium concentration before (63.6 +/- 11. 6 microg/l) and after (64.4 +/- 11.4 microg/l) hemodialysis sessions, although hemoglobin and total serum protein concentrations and serum glutathione peroxidase activities increased (from 98.5 +/- 1.3 to 114.8 +/- 1.5 g/l, from 64 +/- 8 to 71 +/- 9 g/l, and from 16.8 +/- 1.8 to 18.9 +/- 1.9 mU/20 microl, respectively) significantly (p < 0.05) during hemodialysis, indicating hemoconcentration. The selenium concentration doubled, and protein appeared in the dialysates during dialysis session. The correlation of the selenium concentrations with the protein concentrations in the dialysate is significant (p < 0.01) with a Spearman R value of 0.97. CONCLUSION: The results of the present study suggest that selenium is lost through the pores of polysulfone membranes during hemodialysis which is associated with their protein permeability.

The human selenium status in 27 regions of Russia.

Russia is the largest nation in the world and it has vastly different climatic and geochemical conditions. The human selenium status is determined mainly by the selenium intake from foods, whose concentration is subject to geochemical, geological and temporal factors. The data on the selenium status of populations in Russia are scarce and sporadic. This review presents the most recent selenium data acquired using adequate quality assurance measures. Serum samples were obtained from 2462 healthy blood donors between 1990-1996 from 125 locations representing 27 different regions of Russia. Samples of wheat flour and dried milk were also analyzed from most regions. The mean serum selenium concentration per region varied from 0.80 mumol/l in the western regions (Pskov) to 1.84 mumol/l in the easternmost regions (Sakhalin). A low (0.76-1.00 mumol/l) serum selenium concentration was found in only 6% of the locations. In 88% of the locations the mean serum selenium concentrations were moderate (1.01-1.40 mumol/l) and the highest values, > 1.45 mumol/l were found in eight towns. Wheat flour selenium concentrations varied widely from 44 to 557 micrograms/kg depending on the origin. The low values were either domestic or European and the high values of American or Australian origin. A high correlation between serum selenium and wheat flour (r = 0.79) suggests that the selenium status in most instances is determined by high selenium in wheat. Overtly very low or high serum selenium levels were not found in the 27 regions studied in Russia.

Enhanced in vivo lipid peroxidation at elevated plasma total homocysteine levels.

An elevated plasma total homocysteine level (tHcy) is considered an independent risk factor for atherosclerosis. The mechanisms by which hyperhomocysteinemia induces atherosclerosis are only partially understood, but promotion of LDL oxidation and endothelial injury have been suggested. The purpose of this study was to test the hypothesis that a high plasma tHcy is associated in men with increased in vivo lipid peroxidation, as measured by plasma F2-isoprostane concentrations. We investigated this association in a subset of the participants in the Antioxidant Supplementation in Atherosclerosis Prevention (ASAP) study. Of 256 male participants, a subsample of 100 consecutive men was selected for F2-isoprostane assays. The mean tHcy was 11.0 micromol/L, and the mean F2-isoprostanes was 29.6 ng/L. The simple correlation coefficient for association between tHcy and F2-isoprostane was 0.40 (P<0.001). In a linear regression model, the variables with the strongest associations with F2-isoprostane were tHcy (standardized coefficient 0.33, P<0.001), serum triglycerides (0.21, P=0.042), carbohydrate-deficient transferrin (0.15, P=0.132), and plasma lipid-standardized alpha-tocopherol (-0.11, P=0.252) (R2=0.24, P<0. 001 for model). Plasma F2-isoprostane levels increased linearly across quintiles of tHcy (P<0.001). The unadjusted mean (95% confidence interval) F2-isoprostanes was 47.5% greater in the highest tHcy quintile (37.4, 31.1 to 43.6 ng/L) than in the lowest quintile (25.3, 21.3 to 29.3 ng/L). Adjustment for the strongest other determinants of F2-isoprostane reduced this difference to 28. 2% (P=0.010). Our present data suggest that elevated fasting plasma tHcy is associated with enhanced in vivo lipid peroxidation in men.

Selenium and arsenic in the environment in Finland.

A characteristic feature of glaciated Precambrian environments is their low selenium content, as a chalcophile element, Se, replaces sulfur in many of the sulfide minerals, for example, pyrite, chalcopyrite, pyrrhotite, and pentlandite. The average Se concentration in rocks and related till deposits in Finland is in the range of 0.01 to 0.2 mg/kg. Due to geological conditions, Se concentrations in surface and ground water are low in Finland compared with other countries. In a nationwide study dealing with the hydrogeochemistry of headwater streams, the median Se concentration in streams during August to September 1990 was 30 to 180 microg/L. For comparison, Se concentrations in shallow well waters are generally in the range of 50 to 1000 microg/L. The Se concentrations in stream sediments varied from 0.03 to 3.94 mg/kg. There was a highly significant correlation between the Se concentrations in stream water and in stream sediment. The streams with Se concentrations exceeding the general level in both water and sediment were most common in southern Finland. A speciation study on Finnish stream waters revealed that there were equal proportions of Se complexed with humic substances (36%) and Se as a selenate species (36%), whereas selenite accounted for less than 10% of total Se. About 8% of the Se in stream water occurred in particulate form. In an effort to enhance the Se intake of Finns through diet, Se-supplemented fertilizers have been used nationwide since 1985. While greatly improving Se levels in the population, the measure has raised concerns about undesirable environmental effects. Therefore, the amount of Se added to fertilizers has been reduced since 1991. Differing in behavior from Se, arsenic is considered one of the most toxic metals derived from the natural environment. Alarm has been triggered in Finland by the recent lowering from 50 microg/L to 10 microg/L of the upper level of As permissible in potable water, the recent information of high As concentrations in water from drilled bedrock wells, and the findings of international medical studies suggesting that As is a carcinogen. The most important source of As is arsenopyrite (FeAsS). Hence, high As concentrations most frequently occur in areas of sulfide mineralization, often in connection with occurrences of mafic rocks such as gabbros, amphibolites, and peridotites. The As concentrations in till fines, the most common glaciogenic soil type in Finland, reflect those in bedrock. The concentrations in groundwater are controlled by the chemical composition of the bedrock and the soil and prevailing hydrogeochemical conditions, for example, pH and Eh levels. Arsenic concentrations are lowest in surface water and swiftly flowing shallow ground water discharged by springs and are somewhat higher in shallow wells dug into overburden. By far, the highest As concentrations are to be found in wells drilled into bedrock (maximum 1 to 2 mg/L), although the concentrations vary by several orders of magnitude from well to well. The highest probability of encountering deleteriously arsenious well water is in areas with characteristic As anomalies in the till and bedrock. Hence, it is important to understand local geological conditions, particularly in the case of wells drilled into bedrock. The risk of deleteriously high As concentrations occurring in captured springs and shallow wells is slight.

Enteral yeast-selenium supplementation in preterm infants.

AIM: To study the bioavailability of selenium enriched yeast in preterm infants living in a low selenium area (Hungary). METHODS: Thirty six preterm infants were randomly assigned to two groups at birth with respect to selenium supplementation. In the supplemented group (n = 18) infants received 4.8 mg of selenium enriched yeast containing 5 micrograms selenium daily. RESULTS: In the supplemented group the serum selenium concentration increased from 36.1 (+/- 12.8) micrograms/l to 43.5 (7.9) micrograms/l and in the non-supplemented group it decreased from 34.4 (20.4) micrograms/l to 26.1 (16.6) micrograms/l from birth in two weeks. No complications or side effects as a result of supplementation were observed. CONCLUSIONS: Selenium enriched yeast is a safe and an effective form of short term enteral selenium supplementation for preterm infants.

Randomized clinical trial of enteral yeast-selenium supplementation in preterm infants.

There are no data in the literature on effects of supplementing infants with yeast-selenium. We therefore studied the impact of selenium-enriched yeast on the serum selenium concentration of preterm infants living in a selenium-low area (Hungary). Twenty-eight preterm infants with a mean +/- SD birthweight of 962 +/- 129 g and a gestational age of 27 +/- 1 weeks were randomized into two groups at birth with respect to selenium supplementation. In the supplemental group (n = 14) infants received 4.8 mg yeast containing 5 microgram selenium daily with naso-gastric drip during the first 14 postnatal days. The nonsupplemented infants were used as a reference group. In the supplemented group the serum selenium concentration increased from 32.1 +/- 8.5 microgram/l to 41.5 +/- 6.5 microgram/l and in the nonsupplemented group it decreased from 25.9 +/ 6.8 microgram/l to 18.2 +/- 6.4 microgram/l within two weeks. The serum glutathione peroxidase activity increased from 2.97 +/- 0.73 U/20 microliter to 6.42 +/- 3.11 U/20 microliter in the supplemented group, and it did not change significantly (from 3.53 +/- 0.94 U/20 microliter to 3.85 +/- 0.95 U/20 microliter) in the nonsupplemented group. We did not observe any complications or side effects in connection with enteral yeast-selenium supplementation. It is concluded that selenium-enriched yeast is a safe and an effective form of short term enteral selenium supplementation for preterm infants.

Association between elevated plasma total homocysteine and increased common carotid artery wall thickness.

Homocysteine is increasingly recognized as a risk factor for atherothrombotic arterial diseases. We investigated the relation between plasma concentrations of total homocysteine (tHcy) and common carotid artery intima-media wall thickness, measured by B-mode ultrasonography, in 513 asymptomatic men and women from eastern Finland aged 45-69 years. The subjects were examined in 1994-95 at the baseline of the Antioxidant Supplementation in Atherosclerosis Prevention (ASAP) study, a randomized double-blind placebo-controlled two by two factorial trial on the effect of vitamin E and C supplementation in the prevention of atherosclerotic progression. The subjects were assigned into two categories according to the plasma tHcy concentration; concentration over 11.5 micromol/L (highest quartile) or concentration below 11.5 micromol/L. In this study population the mean plasma tHcy concentration was 10.0 micromol/L, and the prevalence of plasma tHcy concentration exceeding 11.5 micromol/L was 33% in men and 18% in women. The adjusted mean intima-media thickness of the right and left common carotid arteries was 1.12 mm in men with elevated plasma tHcy concentration and 1.02 mm in men with a plasma tHcy concentration below 11.5 micromol/L (P = 0.029). In women there was no significant difference. We conclude that elevated plasma tHcy concentrations are associated with early atherosclerosis, as manifested by increased common carotid artery intima-media wall thickness, in middle-aged eastern Finnish men.

Plasma selenoprotein P levels of healthy males in different selenium status after oral supplementation with different forms of selenium.

OBJECTIVE: To assess changes in selenoprotein P levels in plasma from subjects who had received oral supplements of different selenium forms. DESIGN: The same study group participated in two similar selenium supplementation trials, Trial I in 1981 (Levander et al, 1983) and Trial II in 1987 (Alfthan et al, 1991). During Trial II the mean baseline intake of selenium in Finland was higher compared to that during Trial I (100 and 40 microg/d, respectively), due to a nationwide supplementation of fertilisers which started in 1985. SUBJECTS: Fifty healthy Finnish men, 36-60 y old. INTERVENTION: The study group received daily placebo or oral supplements consisting of 200 microg selenium as selenium-enriched yeast, sodium selenate or selenium-enriched wheat (Trial I) or selenium-enriched yeast, sodium selenate or sodium selenite (Trial II). The duration of supplementation periods was 11 (Trial I) and 16 (Trial II) weeks. RESULTS: In Trial I the mean plasma selenoprotein P values in all the supplemented groups increased significantly, approaching a plateau at 2 weeks and reaching maxima at 4 weeks (mean increase 34%, P < 0.05). In Trial II the mean selenoprotein P levels of the supplemented groups were not significantly different from each other or from the placebo group at the start or at any time point of the supplementation period. CONCLUSIONS: At a low selenium status the selenoprotein P levels increased in a similar fashion after supplementation with different forms of selenium, but at a high selenium status no significant effects of supplementation with the same amount of selenium were observed. No differences in selenoprotein P levels were observed for inorganic and organic selenium supplements.

Bioavailability of enteral yeast-selenium in preterm infants.

There is no data or literature on the effects of supplementing infants with yeast selenium, although its intestinal absorption and bioavailability are higher in adults compared with other selenium compounds. The aim of the present investigation was to study the impact of selenium enriched yeast on the serum selenium concentration of preterm infants living in a low selenium area (Hungary). Twenty-eight preterm infants with mean+/-SD birth weight of 962+/-129 g and gestational age 27+/-1 wk were randomized into two groups at birth with respect to selenium supplementation. In the supplemented group (n=14) infants received 4.8 mg yeast selenium containing 5 microg selenium daily via nasogastric drip during the first 14 postnatal days. The nonsupplemented infants were used as a reference group. In the supplemented group, the serum selenium concentration increased from 32.1+/-8.5 microg/L to 41.5+/-6.5 microg/L and in the nonsupplemented group it decreased from 25.9+/-6.8 microg/L to 18.2+/-6.4 microg/L from birth in two weeks time. Compared with previous studies, our results suggest that the bioavailability of selenium in the form of yeast selenium is higher than that of other selenium compounds used for preterm infants. We did not observe any complications or side-effects owing to enteral yeast selenium supplementation. We conclude that selenium enriched yeast is a safe and an effective form of short-term enteral selenium supplementation for infants.

Beta-carotene concentration in buccal mucosal cells with and without dysplastic oral leukoplakia after long-term beta-carotene supplementation in male smokers.

OBJECTIVE: To measure the beta-carotene concentration in buccal mucosal cells in smoking men who had received long-term beta-carotene (BC) supplementation in a controlled trial. To assess the association of cellular BC on the prevalence of dysplasia in oral leukoplakia. DESIGN: An end-of-trial examination of a part of subjects in the Alpha-Tocopherol, Beta Carotene Cancer Prevention Study. SUBJECTS AND METHODS: 343 men who for 5-7 years had received BC (20 mg/d) or alpha-tocopherol (AT) (50 mg/d), or both of these or placebo. BC concentration of buccal mucosal cells was compared in the subjects with BC supplementation (n = 173) to that of those without it (n = 170). Oral mucosae were examined clinically and lesions showing leukoplakia histopathologically. RESULTS: Mean (s.d.) BC concentration in buccal mucosal cells was 7.7 (10.3)mg/kg protein in the subjects who received BC compared to 1.1 (1.7) mg/kg protein in those who did not. The BC concentration in the cells of supplemented subjects correlated with their serum BC levels (P < 0.001). AT supplementation had no effect on BC concentration nor was daily amount of smoking statistically significantly associated with the BC concentration in buccal cells. Altogether 17 subjects showed oral leukoplakia, 7 had dysplasia. In these 7 subjects, the BC concentration in buccal mucosal cells did not differ statistically significantly compared to subjects with only hyperkeratosis (n = 10) (F-test, P = 0.74). CONCLUSIONS: After long-term BC supplementation, BC concentration in oral mucosal cells was 7-fold greater than without supplementation. There was no evidence to support an association between cellular BC concentration and precancerous lesions among the few subjects having them in their oral mucosae.