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Low iron (Fe) stores may result in increased absorption of divalent metals, in particular cadmium (Cd). We have previously shown that in non-smoking women participating in the Norwegian HUNT2 cohort study this also included other divalent metals, e.g. manganese (Mn) and cobalt (Co). The diet is the main source of metals in non-smoking individuals, whereas in smoking individuals tobacco smoke contributes significant amounts of Cd and lead (Pb). The aim of the present study was to investigate the impact of smoking on the relationship between low iron status and divalent metals. Blood concentrations of the divalent metals Cd, Mn, Co, Pb, copper (Cu) and zinc (Zn), determined using an Element 2 sector field mass spectrometer (ICP-MS), were investigated in smoking women of fertile age (range 21-55 years) (n=267) from the HUNT2 cohort. Among these, 82 were iron-deplete (serum ferritin

The effects of an arsenic-rich fish diet and selenium (Se) supplementation on blood arsenic (As), Se, and thyroid hormones were studied in 32 women divided into four equal groups. Groups 1 and 4 received 400 µg Se-methionine daily, group 2 received 400 µg selenite daily, and group 3 received placebo tablets for 15 wk. In addition, groups 1–3 increased their fish intake, eating at least three fish dinners weekly. Mean blood Se concentrations (initially 1.68 ± 0.24 µmol/L) increased twofold in the Se-methionine groups (p < 0.0001) and by 32% in the selenite group (p < 0.01). Group means of blood As concentrations increased by 63% (p < 0.01), 50% (p < 0.01), 106% (p < 0.01), and 29% (p < 0.05) in the four groups, respectively. Analyzed As intake from duplicate portions of consumed fish correlated with final blood As concentrations (r=0.85, p < 0.001, n=32). In the group not receiving Se, there was a positive correlation between final blood As concentrations and plasma T4 : T3 ratio (r=0.80, p < 0.02, n=8). Initially, blood As concentrations correlated negatively with both T3 and T4 in plasma, but this correlation disappeared upon Se supplementation. The results demonstrate that increased intake of fish may influence blood As concentrations and that circulating thyroid hormones may be influenced by Se-As interactions.

Several recent investigations have reported high concentrations of lead in samples of minced cervid meat. This paper describes findings from a Norwegian study performed in 2012 among 147 adults with a wide range of cervid game consumption. The main aim was to assess whether high consumption of lead-shot cervid meat is associated with increased concentration of lead in blood. A second aim was to investigate to what extent factors apart from game consumption explain observed variability in blood lead levels. Median (5 and 95 percentile) blood concentration of lead was 16.6 mg/L (7.5 and 39 mg/L). An optimal multivariate linear regression model for log-transformed blood lead indicated that cervid game meat consumption once a month or more was associated with approximately 31% increase in blood lead concentrations. The increase seemed to be mostly associated with consumption of minced cervid meat, particularly purchased minced meat. However, many participants with high and long-lasting game meat intake had low blood lead concentrations. Cervid meat together with number of bullet shots per year, years with game consumption, self-assembly of bullets, wine consumption and smoking jointly accounted for approximately 25% of the variation in blood lead concentrations, while age and sex accounted for 27% of the variance. Blood lead concentrations increased approximately 18% per decade of age, and men had on average 30% higher blood lead concentrations than women. Hunters who assembled their own ammunition had 52% higher blood lead concentrations than persons not making ammunition. In conjunction with minced cervid meat, wine intake was significantly associated with increased blood lead. Our results indicate that hunting practices such as use of lead-based ammunition, self-assembling of lead containing bullets and inclusion of lead-contaminated meat for mincing to a large extent determine the exposure to lead from cervid game consumption.

Seafood is the predominant food source of several organoarsenic compounds. Some seafood species, like crustaceans and seaweed, also contain inorganic arsenic (iAs), a well-known toxicant. It is unclear whether human biotransformation of ingested organoarsenicals from seafood result in formation of arsenicals of health concern. The present controlled dietary study examined the urinary excretion of arsenic compounds (total arsenic (tAs), iAs, AB (arsenobetaine), dimethylarsinate (DMA) and methylarsonate (MA)) following ingestion of a single test meal of seafood (cod, 780 μg tAs, farmed salmon, 290 μg tAs or blue mussel, 690 μg tAs or potato (control, 110 μg tAs)) in 38 volunteers. The amount of ingested tAs excreted via the urine within 0-72 h varied significantly among the groups: Cod, 74% (52-92%), salmon 56% (46-82%), blue mussel 49% (37-78%), control 45% (30-60%). The estimated total urinary excretion of AB was higher than the amount of ingested AB in the blue mussel group (112%) and also ingestion of cod seemed to result in more AB, indicating possible endogenous formation of AB from other organoarsenicals. Excretion of iAs was lower than ingested (13-22% of the ingested iAs was excreted in the different groups). Although the ingested amount of iAs+DMA+MA was low for all seafood groups (1.2-4.5% of tAs ingested), the urinary DMA excretion was high in the blue mussel and salmon groups, counting for 25% and 11% of the excreted tAs respectively. In conclusion our data indicate a possible formation of AB as a result of biotransformation of other organic arsenicals. The considerable amount of DMA excreted is probably not only due to methylation of ingested iAs, but due to biotransformation of organoarsenicals making it an inappropriate biomarker of iAs exposure in populations with a high seafood intake.

Low iron (Fe) stores may influence absorption or transport of divalent metals in blood. To obtain more knowledge about such associations, the divalent metal ions cadmium (Cd), manganese (Mn), cobalt (Co), copper (Cu), zinc (Zn) and lead (Pb) and parameters of Fe metabolism (serum ferritin, haemoglobin (Hb) and transferrin) were investigated in 448 healthy, menstruating non-smoking women, age 20-55 years (mean 38 years), participating in the Norwegian HUNT 2 study. The study population was stratified for serum ferritin: 257 were iron-depleted (serum ferritin12 microg/L) and 84 had iron deficiency anaemia (serum ferritin12 microg/L and Hb120 g/L). The low ferritin group had increased blood concentrations of Mn, Co and Cd but normal concentrations of Cu, Zn and Pb. In multiple regression models, ferritin emerged as the main determinant of Mn, Co and Cd (p0.001), while no significant associations with Cu, Zn and Pb were found. Adjusted r(2) for the models were 0.28, 0.48 and 0.34, respectively. Strong positive associations between blood concentrations of Mn, Co and Cd were observed, also when controlled for their common association with ferritin. Apart from these associations, the models showed no significant interactions between the six divalent metals studied. Very mild anaemia (110or = Hb120 g/L) did not seem to have any effect independent of low ferritin. Approximately 26% of the women with iron deficiency anaemia had high concentrations of all of Mn, Co and Cd as opposed to 2.3% of iron-replete subjects. The results confirm that low serum ferritin may have an impact on body kinetics of certain divalent metal ions, but not all. Only a fraction of women with low iron status exhibited an increased blood concentration of divalent metals, providing indication of complexities in the body's handling of these metals.

Fish species may contain considerable amounts of trace elements, such as selenium (Se), arsenic (As), and mercury (Hg). The present study investigated the relationships between dietary intake of these elements and cutaneous bleeding time and blood lipids in 32 healthy volunteers. For 6 wk, one group (n = 11) consumed approx 250 g Se-rich fish daily, providing them with an average Se intake of 115 +/- 31 micrograms Se/d, Hg intake of 18 +/- 8 micrograms/d, and As intake of 806 +/- 405 micrograms/d, all values analyzed in 4-d duplicate food collections. To study the effect of Se alone, one group (n = 11) included Se-rich bread in their normal diet, giving them a Se intake (135 +/- 25 micrograms/d) that was comparable to the fish group. A control group (n = 10) ate their normal diet, providing 77 +/- 25 micrograms Se/d, 3.1 +/- 2.5 micrograms Hg/d, and 101 +/- 33 micrograms As/d. The dietary As load strongly correlated both with bleeding times and changes in bleeding times (r = 0.48, p0.01 and r = 0.54, p0.002, respectively). Dietary Hg showed a positive correlation with LDL-cholesterol (r = 0.55, p0.01), whereas dietary Hg in the fish group showed a strong negative relationship with HDL-cholesterol (r = -0.76, p0.01). Selenium seemed to have only a modest effect on bleeding time. Our results suggest that mercury and arsenic from fish may be factors contributing to or modifying some of the known effects of fish ingestion.

The mutual influences of wheat selenium (Se) and n-3 polyunsaturated fatty acids (n-3 PUFA) on plasma Se and indicators of increased oxidative stress were investigated in a randomized, double-blind study with 31 women (23.5 +/- 3.4 yr). Groups 1 and 2 ingested 5.4 g n-3 PUFA daily (as ethyl esters), whereas groups 3 and 4 received placebo capsules. Groups 2 and 3 received 3 slices of high-Se bread daily, providing 115 micrograms Se, in addition to the 77 +/- 26 micrograms Se in the diet. Groups 1 and 4 received placebo slices. Blood samples were drawn at baseline and at 3 and 6 wk. Serum Se concentrations increased in both groups given Se-enriched bread, but significantly less in subjects given n-3 PUFA (group 2). There were no changes in the plasma ratio alpha-tocopherol:mg cholesterol or plasma ascorbic acid levels. In group 1, plasma-conjugated dienes and thiobarbituric acid-reactive substances (TBARS) rose by 130% (p < 0.005) and 126% (p < 0.005), respectively. Two-way ANOVA showed significant interaction effects of Se and n-3 PUFA on changes in conjugated dienes (p = 0.03) and TBARS (p = 0.015), Se treatment apparently modifying the peroxidative effects of n-3 PUFA. In subjects receiving n-3 PUFA, changes in conjugated dienes and TBARS were negatively correlated with changes in serum Se. In summary, n-3 PUFA modified the effect of Se supplementation, whereas Se seemed to modify the peroxidative effects of n-3 PUFA.