High Levels Of Selenium Research Articles

The association between plasma selenium and chronic kidney disease related to lead, cadmium and arsenic exposure in a Taiwanese population.

This study aimed to determine the interaction of red blood cell cadmium and lead, total urinary arsenic, and plasma selenium in chronic kidney disease (CKD). We recruited 220 CKD patients as well as 438 gender- and age-matched controls, and we defined CKD as <60 mL/min/1.73 m2 estimated glomerular filtration rate (eGFR) for three or more consecutive months. Plasma selenium and red blood cell cadmium and lead concentrations were measured by ICP-MS. Urinary arsenic species were determined via HPLC-HG-AAS and were summed to determine the total urinary arsenic concentration. Plasma selenium was positively correlated to eGFR, and subjects with high plasma selenium levels (>243.90 μg/L) had a significantly lower odds ratio (OR) and 95% confidence interval (CI) (0.23, 0.13-0.42) for CKD compared to those with low plasma selenium levels (≤ 196.70 μg/L). High plasma selenium and low red blood cell cadmium or lead concentrations interacted to decrease the OR and 95% CI for CKD (0.12, 0.06-0.26; 0.09, 0.04-0.19). High plasma selenium and low red blood cell lead levels also interacted to increase the eGFR (20.70, 15.56-26.01 mL/min/1.73 m2). This study is the first to suggest that selenium modifies the eGFR and OR in CKD induced by environmental toxicants.

Malabsorption of metals and intestinal parasite infections cause health problems and lower birth rates in the American Bison on the Fort Peck Indian Reservation

BackgroundHerds of American Bison have been raised on pastures of different Indian Reservations in Montana. It has been discovered that many of these Bison have serious health problems related to malnutrition causing lower birth rates. Plants on these reservations absorb unusually high levels of selenium and molybdenum which the animals feed on. Previous studies indicate metals such as copper are necessary for proper health and birthrates. Metals such as Copper, Zinc and Iron are necessary for normal conception rates and will cause retarded growth of the offspring. In addition, poor calving rates in apparently healthy bison with adequate protein and energy in diets might simply be from the different metal deficiencies. We have successively been able to isolate liver samples and fecal samples from Bison on the Fort Peck Indian Reservation to compare with other herds in Montana.HypothesisDecreased absorption of copper, zinc and iron is due to increased absorption of selenium and molybdenum. These difficiencies along with parasitic infections are causing health problems in the bison herds on the Fort Peck Reservation.MethodsWhen Two different herds on the Fort Peck Reservation were tested. One was a cultural herd that is 100% genes and the other is a business herd that contains beef genes. From both herds when the animals are euthanized liver samples and fecal samples are removed for analysis. Body scores were taken to access the states of malnutrition and number of offspring were counted to access birthrates.ResultsLiver tissue specimens collected from bison bulls harvested from the business herd were tested for essential trace mineral levels as well as for the presence of toxic elements. Trace mineral imbalances were detected. Elevated molybedenum (MO) was evident. Elevated Mo can deplete liver copper (Cu) and increase Cu‐molybdenate complexes in plasma or serum. Deficient levels of Cu, manganese and zinc were evident. In addition We determined that bison in the cultural herd were either free of internal parasites or had low burdens of internal parasites. The testing of 22 bison fecal samples found 7 samples to have undetectable ova or parasites per gram of feces. The remaining 15 samples had low levels of Strongyle sp. type ova (0.4–7.78 ova/gram of feces). Three of the 15 samples in addition to Strongyle sp. type ova, had Trichuris sp. (0.4 ova/gram), Nematodirus sp. (0.2–0.67 ova/gram), and/or Coccidia (0.6 ova/gram). In contrast, moderate to heavy burdens of internal parasites were commonly present in bison in conventional herds that we have studied to date.ConclusionsMalabsorption of nutrients such as copper may be caused by increased absorption of selenium, molybdenum or zinc as well as infections from parasites in the Bison digestive tract. We believe these health problems contribute to decreased weights and birthrates of the Bison on the Fort Peck Indian Reservation.Support or Funding InformationThis research is supported by a USDA grant.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Consumption of Brazil nuts with high selenium levels increased inflammation biomarkers in obese women: A randomized controlled trial.

Increased inflammatory response is an important factor in the pathophysiology of obesity. The mineral selenium (Se), of which one of the main food sources is the Brazil nut, has important antioxidant and anti-inflammatory functions through the action of selenoproteins. Thus, the evaluation of the influence of this micronutrient in this context is of great relevance. The aim of this study was to evaluate the effects of Brazil nut intake with high Se concentrations on inflammatory biomarkers and its relation to Se status in obese women. A randomized controlled clinical trial was carried out with 55 women recruited at Clinical Hospital in São Paulo, Brazil. Patients were randomly assigned to either the Brazil nut group (BN) or the control group (CO) and followed up for 2 mo. The BN group consumed 1 unit/d of Brazil nuts (∼ 1261 μg/Se); the CO group did not receive any intervention. At baseline and after 2 mo, analysis of biochemical parameters related to Se status, oxidative stress, and inflammatory biomarkers were performed. At baseline, both groups did not present Se deficiency. In the BN group, a significant increase (P < 0.05) in all Se biomarkers and in gene expression of several proinflammatory parameters (interleukin-6, tumor necrosis factor-α, and Toll-like receptors 2 and 4) were observed after the intervention period. No changes were observed for the CO group. Although there were no changes in plasma inflammatory biomarkers levels, a significant increase in gene expression may be an indication of a proinflammatory stimulus in obesity, induced by the consumption of Brazil nuts with high Se levels.

A Nested Case–Control Study on Plasma Vitamin E and Risk of Cancer: Evidence of Effect Modification by Selenium

BackgroundEvidence from epidemiologic studies has been inconsistent regarding the role of vitamin E in cancer incidence risk. ObjectiveThe aim of this study was to evaluate the prospective association between baseline plasma vitamin E levels and subsequent cancer risk in Chinese adults with hypertension, and to identify effect modifiers. DesignA nested, case–control study was conducted from 20,702 hypertensive participants in the China Stroke Primary Prevention Trial, a randomized, double-blind, controlled trial, conducted from May 2008 to August 2013. ParticipantsThe current study included 229 new cancer cases and 229 controls matched for age (±1 year), sex, treatment group, and study site. Main outcome measuresPlasma vitamin E was measured by liquid chromatography with tandem quadrupole mass spectrometers and plasma selenium was measured by inductively coupled plasma mass spectrometry using Thermo Fisher iCAP Q ICP-MS. Statistical analysesOdds ratios (OR) of cancer in relation to plasma concentrations of vitamin E were calculated using conditional logistic regression models. ResultsMedian follow-up duration was 4.5 years. Overall, vitamin E was not associated with subsequent risk of total cancer (per 1-mg/L [2.3 μmol/L] increase: OR 1.01, 95% CI 0.93 to 1.09) and non-gastrointestinal cancer (OR 1.10, 95% CI 0.98 to 1.24). However, there was a significant, inverse association between vitamin E and gastrointestinal cancer (OR 0.86, 95% CI 0.75 to 0.99), particularly esophageal cancer (OR 0.67, 95% CI 0.48 to 0.95). Moreover, high vitamin E decreased the risk of total cancer (OR 0.91, 95% CI 0.84 to 0.99) and gastrointestinal cancer (OR 0.83, 95% CI 0.73 to 0.95) among patients with high selenium levels (median≥83.7 μg/L [1.1 μmol/L]), and increased the risk of total cancer (OR 1.13, 95% CI 1.00 to 1.26) and non-gastrointestinal cancer (OR 1.25, 95% CI 1.03 to 1.50) among those with low selenium levels (<83.7 μg/L [1.1 μmol/L]). ConclusionsThis study suggests that higher levels of plasma vitamin E are associated with reduced risk of gastrointestinal cancer. High vitamin E decreased the risk of total cancer among patients with high selenium levels, but increased the risk of total cancer among those with low selenium levels.

Production of functional spreadable processed cheese using Chlorella vulgaris.

Chlorella vulgaris alga is one of the most important additives for enhancing the nutritional content of conventional foods, hence positively affecting human health. This alga is known as a rich source of protein, fatty acids, fiber, essential vitamins and minerals. Also, it contains antioxidants, omega 3, antivi- ral and anticancer properties. The aim of this research is increasing the nutritional and potential therapeutic value of processed cheese by using Chlorella vulgaris alga, taking advantage of its high nutritional and health value. The ingredients in the processed cheese blends were mature cheddar cheese, Ras cheese, butter, skimmed milk powder, Emulsifying salts (K-2394, S9s & S4), Chlorella vulgaris (in freeze- dried and slurry forms). Chemical, rheological and sensory evaluation properties were evaluated in processed cheese analogue (PCA) treatments when fresh and after three months of cold storage at 5&ndash;7&deg;C. PCA treat- ments were enriched with 2%, 4% and 6% dried Chlorella vulgaris powder in the cheese blends and 4% Chlorella vulgaris slurry. The incorporation of alga into processed cheese led to an increase in their functional characteristics. The results of sensory evaluation of PCA samples demonstrated that 2% of alga addition was the best treat- ment, followed by 4%, but that the level of 6% was unacceptable to consumers. The studied alga enhanced the cheese analog with the high levels of selenium, zinc, iron, magnesium and potassium. Antioxidant activity in the cheese enhanced with Chlorella vulgaris was higher than the control sample. To improve some proper- ties of PCA, other emulsifying salts (S9S and S4) were tested and the alga was added in the form of slurry with value of 4% into the cheese blend. Both S9S and S4 emulsifying salts were good and the S4 was the best for oiling off and meltability. Also, when using the slurry of Chlorella vulgaris, the granular texture of the cheese analog completely disappeared. The results showed that the alga indeed increased nutrition values and health benefits to the processed cheese, making it a substantial functional food. Therefore, we recommend supporting the manu- facture of the processed cheese analogue with the addition of 2% Chlorella vulgaris alga in soft powder form and 4% Chlorella vulgaris alga in slurry form at the end of the processing.

Chickpea (Cicer arietinum L.) sprouts containing supranutritional levels of selenium decrease tumor growth of colon cancer cells xenografted in immune-suppressed mice

The effect of selenium enriched chickpea sprouts with and without isoflavonoids (IS) on colorectal cancer (CRC) tumor growth was evaluated in immune-suppressed mice xenografted. Two levels of selenium (0.17 and 2.29 µg/g) and isoflavonoids (0 and 2.34 mg/g) were evaluated in the diets. High intake of Se (2.29 µg/g) with and without isoflavonoids increased glutathione peroxidase (GPx) and tioredoxin reductase (TrxR) activities, cholesterol (CHOL), triglycerides (TRIGL) and low-density lipoprotein cholesterol (LDL-C) levels and decreased significantly the tumor growth. Diet containing selenium at 2.29 µg/g and isoflavonoids at 2.34 mg/g levels promoted apoptosis through the overexpression of Fas cell surface death receptor (Fas). High selenium levels in chickpea sprouts exert chemopreventive effects mediated mainly by the antioxidant protection of glutathione peroxidase. Selenized chickpea sprouts represent an excellent source of dietary selenium and isoflavonoids with chemopreventive potential and could be potentially used in the treatment of colorectal cancer.

PROSPECTS OF PRODUCTION OF ALLIUM SEEDS SPROUTS FORTIFIED WITH SELENIUM

Sprouts of agricultural crops seeds are considered to be functional food products with high content of antioxidants. Though seeds of Allium species plants are used in some countries as spices the possibilities of appropriate sprouts utilization have never been investigated so far. Evaluation of perennial and A. cepa seeds biofortification with selenium revealed high nutritional value of the resulting sprouts characterized not only by high selenium content exclusively in a form of selenomethyl selenocysteine (a natural anti carcinogen) but also with high levels of antioxidant activity and high polyphenol content. It was demonstrated that among seven studied representatives of Allium species Allium cepa variety Krasnoye krugevo and perennial onion Allium fistulosum give seeds sprouts with the highest levels of selenium (10500-11000 μg/kg d.w.), polyphenols (9.3-10.8 mg-eq GA/g d.w) and the largest values of antioxidant activity (14.7-17.1 mg-eq GA/g d.w.). Utilization of one g of dried seeds sprouts powder, fortified with selenium provides up to 15.7% of the adequate consumption level of selenium exclusively in a form of selenomethyl selenocysteine possessing powerful anti carcinogenic activity.

Maternal selenium status is profoundly involved in metabolic fetal programming by modulating insulin resistance, oxidative balance and energy homeostasis.

High and low levels of selenium (Se) have been related to metabolic disorders in dams and in their offspring. Their relationship to oxidative balance and to AMP-activated protein kinase (AMPK) is some of the mechanisms proposed. The aim of this study is to acquire information about how Se is involved in metabolic programming. Three experimental groups of dam rats were used: control (Se: 0.1ppm), Se supplemented (Se: 0.5ppm) and Se deficient (Se: 0.01ppm). At the end of lactation, the pups' metabolic profile, oxidative balance, Se levels, selenoproteins and IRS-1 hepatic expression, as well as hepatic AMPK activation were measured. The experimental groups present deep changes in Se homeostasis, selenoproteins and IRS-1 hepatic expression, oxidative balance, AMPK activation ratio and insulin levels. They do, however, have different metabolic profiles. High- and low-Se diets are linked to insulin resistance, yet the mechanisms involved are completely opposite.

A comprehensive review on environmental transformation of selenium: recent advances and research perspectives.

Selenium (Se) is an important micronutrient and essential trace element for both humans and animals, which exist in the environment ubiquitously. Selenium deficiency is an important issue worldwide, with various reported cases of its deficiency. Low selenium contents in some specific terrestrial environments have resulted in its deficiency in humans. However, high levels of selenium in the geochemical environment may have harmful influences and can cause a severe toxicity to living things. Due to its extremely narrow deficiency and toxicity limits, selenium is becoming a serious matter of discussion for the scientists who deals with selenium-related environmental and health issues. Based on available relevant literature, this review provides a comprehensive data about Se sources, levels, production and factors affecting selenium bioavailability/speciation in soil, characteristics of Se, biogeochemical cycling, deficiency and toxicity, and its environmental transformation to know the Se distribution in the environment. Further research should focus on thoroughly understanding the concentration, speciation, Se cycling in the environment and food chain to effectively utilize Se resources, remediate Se deficiency/toxicity, and evaluate the Se states and eco-effects on human health.

Evaluación de bolos selenio sobre parámetros productivos e IgG en cabritos inmunizados con bacterina-toxoide

Mexico has selenium deficiency in most of its territory, this has consequences on animal health, decreasing immunity and productive parameters, such as food consumption and weight gain. The present work evaluated the selenium supplementation in kids in three study groups; One group was supplemented with selenium orally through intraruminal boluses (GBSe) (7 animals); a group was supplemented with selenium parenterally (GSeP) (7 animals); a control group without treatment (GC) (6 animals). Feed intake, weight gain, and immune response were measured trough serum IgG levels against a bacterin-toxoid. It was observed that the supplemented animals had higher levels of selenium in erythrocytes unlike the control group (GC) (p 0.05). Supplementation apparently did not have a clear effect on feed intake and weight gain (p> 0.05). It was possible to increase the concentrations of the mineral in erythrocytes in the supplemented animals. The humoral immune response was influenced by selenium supplementation

Effect of Selenium and Vitamin E Supplementation on Lactate, Cortisol, and Malondialdehyde in Horses Undergoing Moderate Exercise in a Polluted Environment

The objective was to evaluate the supplementation effect of selenium (Se) and DL-tocopherol (E) on blood lactate (LAC), cortisol (COR), and malondialdehyde (MDA), in horses moderately exercised in a polluted environment. Police horses of Mexico City were arranged in a balanced factorial trial (2 × 2) with repeated measures. Low (L) and high (H) levels of Se and E supplementation were evaluated (LSe, 0.1; HSe, 0.3 mg Se/kg dry matter; LE, 1.6; HE, 2.0 IU vitamin E/kg body weight). Experimental groups were LSeLE, LSeHE, HSeLE, and HSeHE. The study that lasted 77 days was distributed as follows: adaptation (28 days), exercise (28 days, three consecutive days of moderate exercise were alternated with four days of inactivity), rest (7 days), and recovery without supplementation for readjustment to police handling (14 days). Once a week (11 week), blood samples for LAC, COR, MDA, blood selenium (B-Se), and α-tocopherol (TOC) quantifications were taken. Data were analyzed with a model for fixed (Se, E, day, and their interactions) and random (the horse nested within the treatment) effects. The relationships between Mexico City's criteria air pollutants (CAPs) concentrations and blood analytes were analyzed by multiple sequential regression analysis. Concentrations of all blood analytes were affected (P < .05) by day while Se affected (P < .05) COR, B-Se, and TOC. No analyte was affected by E (P > .05). Relationships were observed between LAC, COR, MDA, CAP, and day (P < .05). It is concluded that supplementation with high selenium levels could benefit horses exercising in polluted environments. Further research on chemical forms and feeding doses of both Se and E is needed.

Bioremediation potential of bacteria able to reduce high levels of selenium and tellurium oxyanions.

Environmental contamination by Te and Se oxyanions has become a serious concern, with the search for green, ecologically friendly methods for removal gaining ground. Bacteria capable of reducing these highly toxic compounds to a virtually non-toxic elemental form could provide a solution. In this study, four strains of bacteria with potential for bioremediation of Te and Se oxyanions were investigated. Under aerobic conditions over 48h, Erythromicrobium ramosum, strain E5 removed 244µg/ml tellurite and 98µg/ml selenite, Erythromonas ursincola, KR99 203µg/ml tellurite and 100µg/ml selenite, AV-Te-18 98µg/ml tellurite and 103µg/ml selenite and ER-V-8 93µg/ml tellurite and 103µg/ml selenite. In the absence of oxygen, AV-Te-18 and ER-V-8 removed 10µg/ml tellurite after 24 and 48h, respectively and 46 and 25µg/ml selenite, respectively, over 48h. ER-V-8 removed 14µg/ml selenate after 5days. This highlights the great potential of these microbes for use in bioremediation.

Low internal exposure and absence of adverse effects in workers exposed to high air levels of inorganic selenium

Selenium is an essential trace element for humans, but adverse health effects may occur after elevated intake. The margin between it is small. This study aimed to assess external and internal exposure in workers of a selenium-processing plant, in which elemental and inorganic selenium occurred. Selenium was analyzed in the form of the selenium concentration in plasma (Se-P), in erythrocytes (Se-RBC) and in personal air samples (Setotal-Air) of 17 exposed workers. Internal exposure was compared to 20 controls without occupational selenium exposure. For potential effects, glucose, HbA1c, proinsulin, prothrombin time and GPX were determined.Setotal-Air had a maximum of 2394 μg/m3 (median 319 μg/m3), containing a small water-soluble fraction (median 12.7 μg/m3, range 0.07–975 μg/m3). Se-P of the exposed ranged from 62 to 123 μg/L (median 105 μg/L), whereas the median of Se-RBC was 63.4 μg/L blood (range 51.9–92.7 μg/L). Both were significantly higher than the controls. No significant difference was found for the effect parameters.Biological effect monitoring of employees occupationally exposed to very high levels of selenium and inorganic selenium compounds did not show any indication of adverse health effects. The moderate increase of the internal selenium exposure compared to the high ambient exposure to selenium and its compounds suggests an efficient air protection or an extremely low resorption of elemental and inorganic species of selenium via inhalation.

Temporal and geographical variations of mercury and selenium in eggs of Larus michahellis and Larus audouinii from central Mediterranean islands

ABSTRACTIn this study, we determined mercury and selenium levels in abandoned unhatched eggs of the yellow-legged gull (Larus michahellis) and Audouin’s gull (Larus audouinii) collected during 2004–2005 from the Tuscan archipelago and Sardinia (Italy). The different feeding habits of the two species probably determine the different uptakes of trace elements, as the study shows highly significant differences for selenium and mercury levels as well as shell thickness and Hg:Se molar ratio values. Audouin’s gulls nesting on the coasts of the Tuscan archipelago showed significantly higher selenium levels than did gulls from colonies from the islands around Sardinia. Comparisons with a similar investigation previously conducted in the same area suggested that mercury and selenium concentrations, although in line with reports in the literature, were significantly lower than levels encountered in gulls in the early 1980s. Mercury (mg/kg d.w.) dropped from 8.631 to 5.030 in Audouin’s gulls and from 2.509 to 0.828 in yellow-legged gulls. The regional decline in mercury levels following reduced use of the metal in industry and the probable food depletion effects linked to the overfishing of fish prey of these two gull species are discussed as hypotheses that could explain the decrease in mercury levels found in eggs.

Cancer incidence following long-term consumption of drinking water with high inorganic selenium content

Selenium, a trace element to which humans are exposed mainly through diet, has been involved in the etiology of human cancer. We investigated the long-term effects of selenium exposure on cancer incidence using data from a natural experiment in Northern Italy. During the 1970s–1980s, in a part of the Italian municipality of Reggio Emilia, residents were inadvertently exposed to unusually high levels of inorganic hexavalent selenium (selenate) through drinking water. We followed the exposed residents for 28years, generating data on incidence (when available) and mortality rates for selected cancer sites; the remaining municipal residents comprised the unexposed (reference) group. We observed no substantial difference in overall cancer incidence comparing exposed and unexposed cohorts. We detected, however, a higher incidence of cancer at some sites, and for a few of them, namely cancers of the buccal cavity and pharynx, melanoma, urinary tract and lymphoid tissue, the excess incidence was particularly evident in the first period of follow-up but decreased over time. Overall, these results suggest that consumption of water with levels of selenium in its inorganic hexavalent form close to the European standard, 10μg/L, may have unfavourable effects on cancer incidence.

Malabsorption of copper and other nutrients as well as intestinal parasite infections cause health problems and lower birthrates in the American Bison

BackgroundHerds of American Bison have been raised on pastures of different Indian Reservations in Montana. It has been discovered that many of these Bison have serious health problems related to malnutrition causing lower birth rates. Plants on these reservations absorb unusually high levels of selenium and molybdenum which the animals feed on. Previous studies indicate metals such as copper are necessary for proper health and birthrates. Copper is necessary for normal conception rates and will cause retarded growth of the offspring. In addition, poor calving rates in apparently healthy bison with adequate protein and energy in diets might simply be from copper deficiency.HypothesisDecreased copper absorption is due to increased absorption of selenium and molybdenum and parasitic infections.MethodsWhen the animals are euthanized liver samples and fecal samples are removed for analysis. Body scores were taken to access the states of malnutrition and number of offspring were counted to access birthrates.ResultsIncreased toxic levels of selenium (3.7ppm) and Molybdenum (4.2ppm) and low levels of copper (10ppm) have been detected in tissue samples from the livers of the bison. However increased levels of Zinc have also been detected in these animals (125ppm). In addition, the presence or increased levels of intestinal parasites have also been detected in the fecal matter taken these animals. These parasites which include Coccidia and various worm infestations may also be also interfering with the normal absorption of copper and other nutrients in the animals.ConclusionsMalabsorption of nutrients such as copper may be caused by increased absorption of selenium, molybdenum or zinc as well as infections from parasites in the Bison digestive tract.Support or Funding InformationUSDA 2016‐38424‐25559This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Cross-sectional Study: Relationship Between Serum Selenium and Hypertension in the Shandong Province of China.

Although selenium, which is a necessary trace element for the human body, has been considered to be beneficial to the cardiovascular system and helpful to lower blood pressure, more and more evidence shows that high amounts of selenium are a risk factor for hypertension. A random multistage sampling which included the cluster method was performed; a total of 9076 urban and rural residents between 18 and 80years old in the Shandong province of China were investigated by questionnaire, physical examination, and laboratory tests. The prevalence of hypertension was 42.1% in males and 35.3% in females. The mean (standard deviation) selenium concentration was 124.68 (36.32) μg/l in males and 119.54 (31.88) μg/l in females. After adjusting for potential confounders, logistic regression analysis showed that the highest selenium levels were associated with a risk of hypertension (OR = 1.192; 95% CI 1.009-1.407) in females, while there was no significant difference in males (OR = 1.043; 95% CI 0.864-1.259). Our findings suggest that high selenium levels in females are more likely to increase the risk of hypertension compared to similar levels in males. More attention should be paid to the metabolic mechanisms and physiological effects of selenium in females.

Experimentally Induced Selenosis in Yellow-Bellied Slider Turtles ( Trachemys scripta scripta).

Selenosis, or selenium toxicosis, occurs in wildlife and livestock, usually because of excessive intake of selenium via selenium-containing plants. Although it is known that wild slider turtles can accumulate large amounts of selenium, little is known about how selenium exposure may affect these reptiles. In this study, the authors report histopathologic changes in yellow-bellied sliders ( Trachemys scripta scripta) caused by experimental exposure to selenomethionine. Microscopic changes in kidney and claw tissue were most significant and resembled those reported in birds. Turtles in the selenium treatment groups had acute tubular degeneration and regeneration in the kidney, with hyaline droplets in the high-dose animals, and changes in the claws ranging from epidermal hyperplasia with disorganization and intercellular edema to ulceration, and accumulation of seroheterophilic exudate between the epidermis and cornified layer. Although selenium burdens in this study are comparable with values found in wild slider turtles, more data are needed to determine if similar histopathologic abnormalities arise in wild animals exposed to high levels of selenium.

Selenium Homeostasis and Clustering of Cardiovascular Risk Factors: A Systematic Review.

Selenium is a trace element required for a range of cellular functions. It is widely used for the biosynthesis of the unique amino acid selenocysteine [Sec], which is a structural element of selenoproteins. This systematic review focused on the possible relation between selenium and metabolic risk factors. The literature was searched via PubMed, Scopus, ISI Web of Science, and Google Scholar. Searches were not restricted by time or language. Relevant studies were selected in three phases. After an initial quality assessment, two reviewers extracted all the relevant data, whereas the third reviewer checked their extracted data. All evidence came from experimental and laboratory studies. Selenoprotein P is the best indicator for selenium nutritional levels. In addition, high levels of selenium may increase the risk of metabolic syndrome while the lack of sufficient selenium may also promote metabolic syndrome. selenium supplementation in subjects with sufficient serum selenium levels has a contrary effect on blood pressure, LDL, and total cholesterol. According to the bioavailability of different types of selenium supplementation such as selenomethionine, selenite and selenium-yeast, it seems that the best nutritional type of selenium is selenium-yeast. Regarding obtained results of longitudinal studies and randomized controlled trials, selenium supplementation should not be recommended for primary or secondary cardio-metabolic risk prevention in populations with adequate selenium status.

Relationships among Environment, Climate, and Longevity in China.

Human longevity is influenced by environment and nutrition. We considered environmental and nutritional factors relating to longevity in Chinese cities. We found higher 85+/65+ distribution ratios, indicating enhanced longevity, in the coastal and southern regions of China. These areas also featured higher humidity, low standard deviation of monthly temperature, higher levels of selenium (Se) distribution in soil, and greater sea fish consumption. Moderate climate is more conducive to longevity, however, there is no significant difference in longevity between different sub-climatic types within moderate climate; the relation between humidity and longevity is not always positive, the relation between altitude and longevity is not always negative. Nutritional factors like Se and omega-3 fatty acids contained in sea fish were crucial to longevity. In contrast, the consumption of meat and freshwater fish were less related to longevity. Taken together, humidity, altitude, and per capita sea fish consumption, when evaluated via geographically weighted regression, explained 66% and 68% of longevity among Chinese individuals in 2000 and 2010, respectively. Other factors require further discussion.