In vitro bioavailability of total selenium and selenium species from seafood

Influence of Dietary Fibre and Protein Fractions on the Trace Element Bioaccessibility of Turnip Tops (Brassica rapa) Growing under Mediterranean Conditions

The objective of this work was to study the influence of three dietary fibre fractions (pectin, gum arabic and cellulose) and three protein fractions (casein, lactalbumin and soy) on the trace element bioaccessibility (Fe, Mn, Ni, Se and Zn) of turnip tops (B. rapa subsp. Rapa) growing under Mediterranean conditions. Then, it aimed to promote the use of this vegetable not only for direct fresh consumption but also as a main ingredient in the development of food mixtures. The results showed that soluble fibre fractions, such as pectin and gum arabic, can enhance the bioaccessibility of trace elements, such as Fe, Mn, Se and Zn. This effect was not proved for cellulose (an insoluble fibre fraction), in which, at best, no bioaccessibility effect was observed. Regarding the protein fractions, with the exception of Se, caseins and lactalbumin had a neutral effect on improving the trace element bioaccessibility. This did not hold true for soy protein, in which a considerable improvement in the bioaccessibility of Fe, Mn, Se and Zn was determined.

A preliminary predictive model for selenium nutritional status in residents based on three selenium biomarkers

BACKGROUND

Selenium (Se) is an essential nutrient and an important component of many selenoproteins that possess fundamental importance to human health. Selenium deficiency and excess will cause corresponding diseases in the human body. The nutritional health of Se in the human body mainly depends on the daily dietary Se intake of the human body, which in turn depends to a certain extent on the content of Se transmitted along the food chain. This study aims to research the transport of Se through the soil-crop-human chain in regions with different Se levels, and to establish the model between the residents' dietary Se intake and the three Se biomarkers (hair, nails, and plasma), to predict the nutritional health status of Se in residents through Se biomarkers.

METHOD

Carry out field and cross-sectional surveys of populations in Loujiaba Village and Longshui Village. Samples were collected from soil, crops, drinking water, residents' hair, nails, plasma, and diet. The concentration of available Se fractions was extracted from soil samples using 0.1 mol/L K2HPO4. The concentration of total Se for all samples was determined by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS), and the relative standard deviation was less than 5%. In this study, hair, nails, and blood samples were collected from volunteers according to the Declaration of Helsinki and the Ethics Committee of Soochow University. The dietary nutritional structure and dietary Se intake of the population were randomly selected by 12 volunteers using the duplicate portion method. Data were described using mean ± standard deviation. We performed saliency analysis and correlation analysis (with Pearson correlation coefficient), and fitted a regression to evaluate the associations between these variables.

RESULTS

The soil total Se (5201 ± 609.2 μg/kg) and available Se (307.7 ± 83.5 μg/kg) in Luojiaba Village (LJB) were significantly higher than the soil total Se (229.2 ± 32.5 μg/kg) and available Se (21.9 ± 4.0 μg/kg) in Longshui Village (LS). The residents' dietary Se intake of LJB (150.3 ± 2.2 μg/d) was within the World Health Organization (WHO) recommended intake range, while LS (16.0 ± 0.4 μg/d) was close to the range of Keshan disease occurrence, and there was a risk of insufficient Se intake. The correlation analysis found significant positive correlations between residents' dietary Se intake and the three Se biomarkers. According to the preliminary model established in this study, if the daily dietary Se intake of residents reaches the WHO recommended value of 55-400 μg, the hair, nails, and plasma of Se concentration will be 522.1-2850.5 μg/kg, 1069.0-6147.4 μg/kg, and 128.3-661.36 μg/L, respectively.

CONCLUSION

Selenium is transmitted through the soil-crop-human chain, and the Se concentration that enters the human body through the food chain in high-Se areas is significantly higher than that in low-Se areas. The nutritional health status of Se in the human body depends on the daily dietary intake of the human body, and there is a significant correlation between the daily dietary Se intake of the human body and the three biomarkers of Se levels in the human body, so the three biomarkers can be used to evaluate the Se nutritional health of the human.

Selenium in Infants and Preschool Children Nutrition: A Literature Review

Selenium (Se), an essential trace element, is fundamental to human health, playing an important role in the formation of thyroid hormones, DNA synthesis, the immune response, and fertility. There is a lack of comprehensive epidemiological research, particularly the serum Se concetration in healthy infants and preschool children compared to the estimated dietary Se intake. However, Se deficiencies and exceeding the UL have been observed in infants and preschool children. Despite the observed irregularities in Se intake, there is a lack of nutritional recommendations for infants and preschool children. Therefore, the main objective of this literature review was to summarize what is known to date about Se levels and the risk of deficiency related to regular consumption in infants and preschool children.

Influence of Diet on the Bioavailability of Active Components from Zingiber officinale Using an In Vitro Digestion Model

Ginger (Zingiber officinale Rosc.) is a plant known all over the world that is used as a spice and as an ingredient in drinks, dietary supplements, and cosmetics. The growing availability of its fresh rhizomes makes it even more likely to be used in the diet, mainly due to its beneficial health properties and high content of polyphenols (gingerols and shogaols). The main goal and motivation of the authors was to assess the bioavailability of active substances contained in the extract from ginger rhizomes in the presence of various types of diets using the in vitro digestion method, enabling simulation of the processes occurring during the digestion and absorption of metabolites in the small intestine. For the qualitative and quantitative analyses, the HPLC-MS (High Performance Liquid Chromatography-Mass Spectrometry) and HPLC (High Performance Liquid Chromatography) techniques were used, respectively. Based on the obtained results, it was found that the best bioavailability of the selected ginger polyphenols (6-gingerol, 8-gingerdione, 8-shogaol, and 10-gingerdione) was estimated for a high-fiber diet, while the weakest results were obtained for standard and basic diets. In the case of the high-fiber diet, the bioavailability of the mentioned compounds was estimated as 33.3, 21.4, 6.73, and 21.0%, while for the basic diet, it was only 21.3, 5.3, 2.0, and 1.0%, respectively.

Effects of Selenium Enrichment on Dough Fermentation Characteristics of Baker's Yeast

In this research, the effect of selenium (Se) enrichment on dough fermentation characteristics of yeast and the possible mechanisms was investigated. Then, the Se-enriched yeast was used as starter to make Se-enriched bread, and the difference between Se-enriched bread and common bread was investigated. It was found Se enrichment increased CO₂ production and sugar consumption rate of Saccharomyces cerevisiae (S. cerevisiae) in dough fermentation, and had positive impacts on final volume and rheological index of dough. The mechanism is possibly related to higher activity and protein expression of hexokinase (HK), phosphofructokinase (PFK), pyruvate kinase (PK), citrate synthase (CS), isocitrate dehydrogenase (ICD), and α-ketoglutarate dehydrogenase (α-KGDHC) in Se-enriched yeast. Moreover, Se-enriched bread (Se content: 11.29 μg/g) prepared by using Se-enriched yeast as starter exhibited higher overall acceptability on sensory, cell density in stomatal morphology, and better elasticity and cohesiveness on texture properties than common bread, which may be due to effect of higher CO₂ production on dough quality. These results indicate Se-enriched yeast could be used as both Se-supplements and starter in baked-foods making.

In Vitro Evaluation of Bioavailability of Se from Daily Food Rations and Dietary Supplements

Bioavailability refers to a fraction of a substance that is potentially absorbed from the gastrointestinal tract and enters the systemic circulation (blood). This term is related to various substances, including minerals, that are present in a complex matrix of food which is consumed every day as natural products and pharmaceutical preparations, e.g., dietary supplements. The purpose of the study was to assess the bioavailability of Se from selected dietary supplements, with the simultaneous assessment of the effect the diet type (standard, basic and high-residue diets) has on relative bioavailability. The research included a two-stage in vitro model of digestion using cellulose dialysis tubes of the food rations with the addition of dietary supplements. Se was determined using the ICP-OES method. The bioavailability of Se from dietary supplements, in the presence of food matrix, was determined to be within the range of 19.31-66.10%. Sodium selenate was characterized by the highest value of this parameter, followed by organic forms and sodium selenite. The basic diet, characterized by moderate protein and high carbohydrate and fiber contents, positively influenced the bioavailability of Se. The bioavailability of Se was also influenced by the pharmaceutical form of the product-the highest was for tablets, followed by capsules and coated tablets.

In Vitro Bioaccessibility of Selenium from Commonly Consumed Fish in Thailand

Selenium (Se), abundantly obtained in fish, is a crucial trace element for human health. Since there are no data on Se bioaccessibility from commonly consumed fish in Thailand, this study assessed the in vitro bioaccessibility of Se using the equilibrium dialyzability method. The five fish species most commonly consumed in Thailand were selected to determine total Se content using several preparation methods (fresh, boiling, and frying). Equilibrium dialyzability was used to perform in vitro bioaccessibility using enzymatic treatment to simulate gastrointestinal digestion for all boiled and fried fish as well as measuring Se using inductively coupled plasma triple quadrupole mass spectrometry (ICP-QQQ-MS). Two-way ANOVA with interaction followed by Tukey’s honestly significant difference (HSD) post hoc test revealed that boiled Indo-Pacific Spanish mackerel, longtail tuna, and short-bodied mackerel were significantly higher in Se content than striped snakehead and giant sea perch (p < 0.05). For fried fish, longtail tuna showed the highest Se content (262.4 µg/100 g of product) and was significantly different compared to the other fish (p < 0.05, estimated marginal means was 43.8−115.6 µg/100 g of product). Se bioaccessibilities from striped snakehead (70.0%) and Indo-Pacific Spanish mackerel (64.6%) were significantly higher than for longtail tuna (p < 0.05). No significant difference in bioaccessibility was found in terms of preparation method (i.e., boiling and frying). In conclusion, the fish included in this study, either boiled or fried, have high Se content and are good sources of Se due to high bioaccessibility.

Gene Identification, expression analysis and molecular docking of ATP sulfurylase in the selenization pathway of Cardamine hupingshanensis

BACKGROUND

ATP sulfurylase (ATPS) is a crucial enzyme for the selenate assimilation pathway in plants.

RESULTS

In this study, genome-wide and comparative analyses of ATPS in Cardamine hupingshanensis, including sequence and structural analyses, were performed. The expression of ChATPS gene family members in C. hupingshanensis under selenium (Se) stress was also investigated, and our results suggest that ChATPS1-2 play key roles in the response to Se stress. Nine ATPS genes were found from C. hupingshanensis, which share highly conserved sequences with ATPS from Arabidopsis thaliana. In addition, we performed molecular docking of ATP sulfurylase in complex with compounds ATP, selenate, selenite, sulfate, and sulfite. ChAPS3-1 was found to have stronger binding energies with all compounds tested. Among these complexes, amino acid residues Arg, Gly, Ser, Glu, and Asn were commonly present.

CONCLUSION

Our study reveals the molecular mechanism of C. hupingshanensis ATP sulfurylase interacting with selenate, which is essential for understanding selenium assimilation. This information will guide further studies on the function of the ChATPS gene family in the selenium stress response and lay the foundation for the selenium metabolic pathway in higher plants.

Urinary metals as influencing factors of coronary heart disease among a population in Guangzhou, China

The cardiovascular system is highly sensitive to toxic metal exposure and trace element dysregulation. However, previous findings relating to metal exposure and coronary heart disease (CHD) have partially been conflicting and difficult to exhibit the combined effect of metal mixtures. This case-control study investigated urinary concentrations of ten metal/metalloids among clinically-diagnosed CHD patients and healthy adults during May to December 2021 in Guangzhou, China. We found that cadmium (Cd) status in urine from CHD patients was remarkably higher than its reference, while chromium (Cr), nickel (Ni), copper (Cu) and selenium (Se) concentrations were lower (p < 0.05). Spearman correlation analysis showed that urinary arsenic (As) and Se were highly correlated (r_s=0.830, p < 0.001), indicating their similar sources. Principal component analysis (PCA) exhibited denser distribution of Cd-Sn in cases than in controls. Logistic regression analysis exhibited significant associations between urinary Cd (adjusted OR: 1.965, 95% CI: 1.222-3.162), Se (0.787, 95% CI: 0.695-0.893), Ni (0.493, 95% CI: 0.265-0.916) and CHD risk. Quantile g-computation showed negative joint effect of metal mixtures on CHD (adjusted OR: 0.383, 95% CI: 0.159-0.932) (p < 0.05), suggesting the need for supplementing essential trace elements. The negative partial effect was primarily attributed to Se and Ni, while positive partial effect was mainly due to tin (Sn) and Cd. Nevertheless, we also found a quantile increase of Cd-Sn level was negatively correlated with 8.26% (95% CI: 3.44-13.08%) decrease of high-density lipoprotein cholesterol (p < 0.001), and 71.2% of the joint effect attributed to Cd. Based on random forest, Se, Cd and Ni were found to be the dominant influencing factors of CHD. The role of Ni in CHD is yet to be uncovered, while excessive Cd exposure and low Se status among CHD patients need to be mitigated.

Influence of culinary treatment on the concentration and on the bioavailability of cadmium, chromium, copper, and lead in seafood

BACKGROUND

Seafood present important advantages for human nutrition, but it can also accumulate high levels of toxic and potentially toxic elements. Culinary treatments could influence seafood chemical element content and element bioavailability. In this study, the influence of culinary treatments on the total concentration and on the bioavailability of Cd, Cr, Cu and Pb in shark, shrimp, squid, oyster, and scallop was assessed.

METHODS

Boiling, frying, and sautéing with or without seasonings (salt, lemon juice and garlic) were evaluated. Total concentration and bioavailability of Cd, Cr, Cu and Pb in seafood after all these culinary treatments were compared with those in uncooked samples. Analytes were determined by triple-quadrupole inductively coupled plasma mass spectrometry (ICP-MS/MS). An alternative to express the results avoiding underestimated or overestimated values was proposed.

RESULTS

The analytes concentration in seafood without culinary treatment varied from 0.0030 μg g^-1 (shrimp) to 0.338 μg g^-1 (oyster) for Cd; 0.010 μg g^-1 (squid) to 0.036 μg g^-1 (oyster) for Cr; 0.088 μg g^-1 (scallop) to 8.63 μg g^-1 (oyster) for Cu, and < 0.005 μg g^-1 (shrimp, squid and oyster) to 0.020 μg g^-1 (shark) for Pb. Only Cd (in scallop) was influenced by culinary treatments (reduction from 37 to 53 % after boiling, frying, and sautéing). Bioavailability percentage varied from 11% (oyster) for Cd; 18% (oyster) to 41% (shark) for Cr; 6% (shark) for Cu, and 8% (oyster) for Pb. Bioavailability percentage was not influenced by culinary treatments.

CONCLUSION

Cadmium concentration was reduced in scallop after some culinary treatments (reduction o 37-53% after boiling, frying, and sautéing), but bioavailability percentage was not influenced. The employed analytical method was adequate for the purpose, presenting import results for food safety assessment about the influence of culinary treatments on metals concentration and bioavailability in seafood.

Development and application of a HPLC-ICP-MS method to determine selenium speciation in muscle of pigs treated with different selenium supplements

Dietary selenium deficiency is recognized as a global problem. Pork is the most widely consumed meat throughout the world and an important source of selenium for humans. In this study, a reliable approach was developed for analyzing selenium and its speciation in the muscles of pigs after different selenium treatments. The selenium source deposition efficiency was ranked as: selenomethionine > methylselenocysteine > selenite, and the muscle selenium content had a dose effect with selenomethionine supplementation. In total, four species of selenium were detected in the muscles of pigs and the distributions of these selenium species were greatly affected by the dietary selenium supplementation forms and levels. Selenomethionine (>70% of total selenium) and selenocystine (>11%) were the major selenium species, followed by methylselenocysteine and selenourea. Therefore, selenium-enriched pork produced from selenomethionine is a good source for improving human dietary selenium intake.

Bioavailability and Bioactivity of Selenium from Wheat ( Triticum aestivum), Maize ( Zea mays), and Pearl Millet ( Pennisetum glaucum), in Selenium-Deficient Rats

This study examined the bioavailability and bioactivity of selenium (Se) from staple cereals, wheat, pearl millet, and maize, in Se-deficient rats (Wistar strain (OUT-Wister, IND-cft (2c)). The bioavailability and bioactivity of Se were determined by measuring the Se contents of the tissue and organs and activities of Se-dependent enzymes. Se-deficient rats were repleted with Se through wheat, pearl millet, and maize. The wheat diet exhibited the highest bioavailability of Se, followed by pearl millet and maize. The bioactivity of Se, as indicated by the activity of the Se-dependent enzymes, was found to be significantly ( p < 0.001) higher in the organs of rats fed the wheat diet, followed by pearl millet and maize diets. The deficiency of Se resulted in a significant decrease ( p < 0.001) in the activity of antioxidant enzymes in circulation and organs. The staples wheat, pearl millet, and maize have a high bioavailability of Se.

Selenium and mercury concentration in drinking water and food samples from a coal mining area in Brazil

Selenium (Se) is an essential element for human health and can also alleviate the toxicity of elements such as mercury (Hg), which is considered deleterious to health. The study area is an important coal mineral region in Brazil, generating 40% of all Brazilian coal. During the coal mining process, Se and Hg are released, which can induce potential human health risks via the food chain. The purpose of the present study is to determine total Se and its species and total Hg in drinking water and food locally produced from a coal mining area, to assess the impact of coal mining. The samples were collected in two cities, with and without coal mining influence. Total Se levels in drinking water and food were assessed by inductively coupled plasma mass spectrometry (ICP-MS) and its species by high-performance liquid-ICP-MS, while total Hg was determined by cold vapor atomic fluorescence spectrometry. Drinking water (1.1 ± 0.2 mg L^-1 dry weight) (p = 0.02) and tomatoes (1.5 ± 0.1 mg kg^-1 dry weight) (p = 0.01) from the coal mining area had higher total Se concentration than the control area. The highest Se concentrations were found in animal-based food (6.4 ± 0.8 mg kg^-1 dry weight) with an important contribution of Se IV (65%). The analyzed sample did not accumulate a significant amount of Hg. Future studies on the estimates of daily intake of these elements and dietary pattern of the population are needed to make appropriate dietary recommendations and support public health action.

In vitro bioaccessibility of selenoamino acids from selenium (Se)-enriched Chlorella vulgaris biomass in comparison to selenized yeast; a Se-enriched food supplement; and Se-rich foods

Selenium (Se) is an indispensable microelement in our diet and health issues resulting from deficiencies are well documented. Se-containing food supplements are available on the market including Se-enriched Chlorella vulgaris (Se-Chlorella) which accumulates Se in the form of Se-amino acids (Se-AAs). Despite its popular uses, data about the bioaccessibility of Se-AAs from Se-Chlorella are completely missing. In the present study, gastrointestinal digestion times were optimized and the in vitro bioaccessibility of Se-AAs in Se-Chlorella, Se-yeast, a commercially available Se-enriched food supplement (Se-supplement) and Se rich foods (Se-foods) were compared. Higher bioaccessibility was found in Se-Chlorella (∼49%) as compared to Se-yeast (∼21%), Se-supplement (∼32%) and Se-foods. The methods used in production of Se-Chlorella biomass were also investigated. We found that disintegration increased bioaccessibility whereas the drying process had no effect. Similarly, temperature treatment by microwave oven also increased bioaccessibility whereas boiling water did not.

Dietary intake of cadmium, chromium, copper, manganese, selenium and zinc in a Northern Italy community

This study provides the dietary intakes of six trace elements (cadmium, chromium, copper, manganese, selenium and zinc), generally characterized by both nutritional and toxicological features depending on their exposure. Being diet the most relevant source of exposure to trace elements in non-professionally exposed subjects, we measured content of these trace elements in foods composing the typical Italian diet using inductively coupled plasma-mass spectrometry, and assessing dietary habits using a validated semi-quantitative food frequency questionnaire we eventually estimated dietary daily intake of trace elements in a Northern Italian community. In the 890 analyzed food samples, the main contributors to cadmium intake are cereals, vegetables and sweets, while cereals, beverages and vegetable are to primary source of manganese. The primary contributors for copper are cereals, fresh fruits and vegetables, while for chromium are beverages, cereals and meat. The main source of selenium intake are cereals and meat, followed by fish, seafood and milk and dairy products, while of zinc intake are meat, cereals, milk and dairy products. In our Italian population sample, the estimated median (interquartile range) dietary daily intakes are 5.00 (3.17-7.65), 56.70 (36.08-86.70) and 66.53 (40.04-101.32) μg/day for cadmium, chromium and selenium, and corresponding figures are 0.98 (0.61-1.49), 2.34 (1.46-3.52) and 8.50 (5.21-12.48) mg/day for copper, manganese and zinc. The estimated intakes are generally within the average intake reported in other European populations, and in such cases well above the daily dietary intakes recommended by national international agencies, avoiding the risk of excess or deficiency. The present estimated intake data can be used to examine a specific trace element of interest and would afford enhanced health protection from those trace elements characterized by both nutritional and toxicological effects.

Assessing bioaccessibility of Se and I in dual biofortified radish seedlings using simulated in vitro digestion

Selenium (Se) and iodine (I) are essential elements for humans, and biofortification of vegetables with these elements is an effective way to amend their deficiencies in the diet. In this study, the distribution and transformation of Se and I species were investigated in radish seedlings that were simultaneously supplemented with these two elements; the fate and the bioaccessibility of Se and I species were dynamically surveyed in the oral, gastric and intestinal phases using a simulated in vitro digestion method. The radish seedlings were cultivated in hydroponic conditions with Se (IV), Se (VI), I^- and IO₃^- (each 1 mg L^-1). The results revealed that Se-methylselenocysteine (MeSeCys), selenocystine (SeCys₂), selenomethionine (SeMet) and Se (VI) were present in radish, and MeSeCys was the dominant species in both gastric and intestinal extracts, comprising 32.7 ± 1.5% and 39.6 ± 1.1% of the total content, respectively. I^- was also the dominant species, which accounted for 57.1 ± 2.1%, 46.6 ± 1.5% and 68.8 ± 1.8% of the total digested content respectively in the oral, gastric and intestinal extracts. Meanwhile, IO₃^- was absent and organic I accounted for approximately 20%. The bioaccessibility of Se and I in the intestinal phase reached 95.5 ± 2.5% and 85.8 ± 0.9%, respectively; although after dialysis through membranes, the data reduced to 60.1 ± 2.8% and 39.6 ± 0.8%, respectively. Contents of MeSeCys and I^- increased from the oral to intestinal phase and the bioaccessibility of both Se and I in radish was above 85%. So radish is suitable as a potential dietary source of Se and I with biofortification.

Selenium Analysis and Speciation in Dietary Supplements Based on Next-Generation Selenium Ingredients

Selenium is essential for humans and the deficit of Se requires supplementation. In addition to traditional forms such as Se salts, amino acids, or selenium-enriched yeast supplements, next-generation selenium supplements, with lower risk for excess supplementation, are emerging. These are based on selenium forms with lower toxicity, higher bioavailability, and controlled release, such as zerovalent selenium nanoparticles (SeNPs) and selenized polysaccharides (SPs). This article aims to focus on the existing analytical systems for the next-generation Se dietary supplement, providing, at the same time, an overview of the analytical methods available for the traditional forms. The next-generation dietary supplements are evaluated in comparison with the conventional/traditional ones, as well as the analysis and speciation methods that are suitable to reveal which Se forms and species are present in a dietary supplement. Knowledge gaps and further research potential in this field are highlighted. The review indicates that the methods of analysis of next-generation selenium supplements should include a step related to chemical species separation. Such a step would allow a proper characterization of the selenium forms/species, including molecular mass/dimension, and substantiates the marketing claims related to the main advantages of these new selenium ingredients.

Fe, Zn and Se Bioavailability in Chicken Meat Emulsions Enriched with Minerals, Hydroxytyrosol and Extra Virgin Olive Oil as Measured by Caco-2 Cell Model

There is a high demand for functional meat products due to increasing concern about food and health. In this work, Zn and Se bioavailability was increased in chicken meat emulsions that are enriched with Hydroxytyrosol (HXT), a phenolic compound obtained from olive leaf. Six different chicken emulsions were elaborated. Three were made with broiler chicken meat supplemented with inorganic Zn and Se: control, one with HXT (50 ppm) added and one with HXT (50 ppm) and Extra Virgin Olive Oil (EVOO) (9.5%) added; and, three were made with chicken meat from chickens fed a diet that was supplemented with organic Zn and Se: control, one with HXT (50 ppm) added and one with HXT (50 ppm) and EVOO (9.5%) added. The samples were digested in vitro and the percent decomposition of phenolic compounds was measured by HPLC. Mineral availability (Fe, Zn and Se) was measured by cell culture of the Caco-2 cell line and the results were compared with mineral standards (Fe, Zn, and Se). The data obtained showed that neither HXT resistance to digestion nor Fe availability was affected by the presence of organic Zn and Se or phenolic compounds. Zn uptake increased in the presence of HXT, but not when its organic form was used, while Se uptake increased but it was not affected by the presence of HXT. It was concluded that the enrichment of meat—endogenously with organic minerals and exogenously with phenolic compounds—could be considered an interesting strategy for future research and applications in the current meat industry.

Diet composition and serum levels of selenium species: A cross-sectional study

Selenium is a trace element of both nutritional and toxicological interest, depending on its dose and chemical form. Diet is the primary source of exposure for most individuals. We sought to investigate the influence of food intake on serum levels of selenium species. Among fifty subjects randomly selected from a Northern Italian population, we assessed dietary habits using a validated semi-quantitative food frequency questionnaire. We also measured circulating levels of selenium species in serum using high pressure liquid chromatography associated with inductively-coupled plasma dynamic reaction cell mass spectrometer. Circulating levels of inorganic selenium, the most toxic selenium species, were positively associated with intake of fish, legumes and dry fruits, and inversely associated with intake of dairy products and mushrooms. Concerning the organic selenium species, selenoproteinP-bound selenium was inversely associated with intake of fish, fresh fruits, vegetables, and legumes, while selenocysteine-bound selenium positively associated with intake of fresh fruit, potato, legume and mushroom. In the present study, intakes of different foods were correlated with different types of selenium species. These results have important public health implications when assessing the nutritional and toxicological potential of diet composition with reference to selenium exposure.

Bioaccessibility of selenium, selenomethionine and selenocysteine from foods and influence of heat processing on the same

Selenium (Se) is an essential nutrient with diverse physiological functions. The selenium content of commonly consumed cereals, pulses and green leafy vegetables (GLV) was determined. Bioaccessibility of Se, and its organic forms selenomethionine (SeMet), and selenocysteine (SeCys2) was also examined, and the effect of heat processing on the same was studied. The bioaccessibility of Se in cereals ranged from 10% to 24%, that of pulses was between 12% and 29%, and of GLV, 10-31%. The concentration of SeMet in the dialysates of the cereals, pulses and GLV ranged from 5.15 to 28.7, 2.7 to 36.2, and 0.03 to 5ngg(-1), respectively. The concentration of SeCys2 in the dialysates of the foods examined was negligible. Heat processing significantly decreased the bioaccessibility of Se, SeMet and SeCys2. This is the first report on the bioaccessibility of Se and its major organic forms from commonly consumed staples, and the effect of heat processing on the same.

The effect on selenium concentrations of a randomized intervention with fish and mussels in a population with relatively low habitual dietary selenium intake

Selenium status of the Danish population is below that assumed optimal for the suggested protective effects against chronic diseases, including certain cancers. Fish and shellfish are important dietary sources of selenium in Denmark. We investigated the effect of increased fish and mussel intake on selenium blood concentrations in a population with relatively low habitual dietary selenium intake. We randomly assigned 102 healthy men and women (all non-smokers) aged 48–76 years to an intervention group (n = 51) or a control group (n = 51). Intervention participants received 1000 g fish and mussels/week for 26 weeks (~50 μg selenium/day). Controls received no intervention. Non-fasting blood samples were taken and whole blood selenium was determined using inductively coupled plasma-mass spectrometry (ICP-MS), and plasma selenoprotein P (SelP) was determined by high performance liquid chromatography coupled to ICP-MS. All available observations were included in linear multiple regression analysis to evaluate the effect of the intervention. The difference in mean change for intervention compared with control persons was 14.9 ng/mL (95% CI: 10.2, 19.7) for whole blood selenium, and 7.0 ng/mL (95% CI: 3.1, 10.9) for plasma SelP (Weeks 0–26). Selenium concentrations were significantly increased after 26 weeks of intervention, albeit to a lower degree than expected.

Selenium speciation in human serum and its implications for epidemiologic research: a cross-sectional study

Observational studies addressing the relation between selenium and human health, particularly cancer risk, yielded inconsistent results, while most recent randomized trials showed a fairly consistent pattern suggesting null or adverse effects of the metalloid. One of the most plausible explanations for such inconsistencies is inadequate exposure assessment in observational studies, commonly carried out by measuring total Se content without taking into account the specific exposure to the individual chemical forms of the metalloid, whose toxic and nutritional properties may vary greatly. Data on the distribution of these species in human blood and their correlation with overall selenium levels are very limited. The concentrations of organic and inorganic selenium species were analyzed in serum of fifty subjects sampled from the general population of the municipality of Modena, northern Italy, aged from 35 to 70 years. Samples were collected during a 30-month period, and determinations of selenium species were carried out using high pressure liquid chromatography coupled with inductively coupled plasma dynamic reaction cell mass spectrometry. The majority of selenium was found to be present as organic species, but the inorganic forms showed higher levels than expected. These species showed limited correlations with age, sex and body mass index, while the organic forms increased in subjects consuming selenium-containing dietary supplements and decreased in smokers. The length of the sample storage period strongly influenced the distribution of selenium compounds, with a clear tendency towards higher inorganic and lower organic selenium levels over time. In multivariate analysis adjusting for potential confounders, total serum selenium correlated with human serum albumin-bound selenium and, in males, with two organic species of the metalloid (selenocysteine and glutathione peroxidase-bound selenium), while little association existed with the other organic forms and the inorganic ones. These findings highlight the potential for exposure misclassification of observational epidemiologic investigations based on overall selenium content in blood and possibly other tissues, and the critical role of the storage conditions for speciation analysis.