To explore the relationship between selenium deficiency in cancer and nutritional factors, we measured the serum concentrations of selenium in 1978-1983 in patients with gynaecological cancer (N = 277) and correlated these with the estimated daily intake of selenium, which varies in Finland depending on the proportion of selenium-rich imported grain. The selenium concentration increased significantly from 1978-1979 to 1982 in the series of all cancer patients (p less than 0.001) and separately in cases of cervical (p less than 0.001) and endometrial cancer (p less than 0.02), parallel to the increased daily intake of selenium. The serum level of selenium decreased in 1983, when the import of selenium-rich grain was reduced. Low serum selenium in cancer patients thus seems to be mainly dependent on dietary factors.
We propose scientific substantiation of optimization of the balance between the intensity of free radical oxidation and activity of antioxidant defense in students by treatment with biogenic substance Selenes+ and exposure to additional physical exercises. A relationship between qualitative and quantitative parameters of growth, development, biochemical profile, status of the cardiovascular system, and improvement of adaptogenesis in first- and second-year students was demonstrated.
The hypothesis that low selenium may in some circumstances be a risk factor for lung cancer was investigated in a case-control study nested within a longitudinal study. Serum samples from 9,101 cancer-free individuals were collected and stored at -20 degrees C by the Finnish Mobile Clinic in 1968-1971 and 1973-1976. During follow-up until the end of 1991, 95 cases of lung cancer were diagnosed. Selenium concentrations were determined from the serum samples of the cases and 190 controls, individually matched for sex, age, and place of residence. Mean levels of serum selenium in cases and controls were 53.2 microg/liter and 57.8 microg/liter, respectively. The relative risk of lung cancer between the highest and lowest tertiles of serum selenium, adjusted for smoking, serum alpha-tocopherol, serum cholesterol, serum copper, serum orosomucoid, and body mass index (kg/m2), was 0.41 (95% confidence interval (CI) 0.17-0.94). The association was stronger at lower levels (
Human selenium levels were estimated in 28 towns and settlements of the Murmansk, Vologda, Arkhangelsk regions and Karelia. These were found to be 90-102 micrograms/l in these areas, the lowest ones being detected in Petrozavodsk. Kondopoga, Suoyarvi, and Kovdor, the highest in Kola. The findings suggest that the higher selenium levels in the population in the north and south of the regions (the Murmansk and Vologda regions) is provided by the imported wheat flour with high selenium levels. They show it necessary to transport foodstuffs containing selenium into the areas where there may be this compound deficiency.
Selenium status was determined in 15 consecutive postoperative patients receiving short-term total parenteral nutrition (TPN) using both serum selenium concentration and glutathione peroxidase (GSH-Px) activity as an indicator of body selenium status. The serum selenium concentration was significantly (p less than 0.001) lower in TPN patients (0.52 +/- 0.16 mumol/l, mean +/- SD) than in age- and sex-matched controls (1.08 +/- 0.17 mumol/l). Serum selenium in TPN patients ranged from 0.28 to 0.79 mumol/l and was associated with the duration of TPN. The lowest selenium values was found in patients who had received TPN over 3 weeks (0.35 +/- 0.06 mumol/l) as compared to patients receiving TPN for 1-3 weeks (0.61 +/- 0.13 mumol/l; p less than 0.01). Serum GSH-Px activity in TPN patients was also low (116 +/- 21 U/l) and ranged from 75 to 159 U/l. A significant positive correlation was found between serum selenium and GSH-Px activity (r = 0.520; p less than 0.05) whereas serum selenium and GSH-Px activity did not correlate significantly with liver function tests and body mass index. This study suggests that also short-term TPN patients may be at risk of selenium deficiency.
For humans, ecological and epidemiological results are reported that show a relationship between the serum selenium concentration and cardiovascular disease in populations where low serum selenium concentrations are found, e.g., in Eastern Finland. From clinical studies done in Germany (FRG and GDR), Finland, and Sweden, subnormal serum selenium and partially whole blood selenium concentrations are reported in patients with acute myocardial infarction. For patients with coronary arteriosclerosis, subnormal serum selenium concentrations are reported from the USA and Germany and subnormal whole blood selenium concentrations from Germany. Subnormal serum and subnormal whole blood selenium concentrations of patients with cardiomyopathy are reported from non Keshan disease affected areas in Germany, France, and China. In selenium deficiency, an accumulation of lipid peroxides in the heart may occur, especially under ischemic conditions and if ischemic tissue is reperfused. Lipid peroxides in the heart may damage the cell membrane and may lead to an impaired calcium transport with an uncontrolled calcium accumulation in the cell. This may result in an activation of phospholipids, and, in consequence, to an enhanced formation of arachidonic acid. An increased concentration of lipid peroxides owing to selenium deficiency may shift the prostaglandin synthesis from prostacyclin to thromboxane, causing enhanced blood pressure and platelet aggregability. From animal experiments, it is known that selenium protects against cardiotoxic elements, cardiotoxic xenobiotics, and viral infections that affect the heart. Selenium deficiency may also be a secondary factor in the causation of hypertension and myocardial ischemia.
Low-Se status may be associated with a higher risk of notably advanced prostate cancer. In a Danish population with a relatively low Se intake, we investigated the association between pre-diagnostic Se status and (1) the risk of total, advanced and high-grade prostate cancer and (2) all-cause and prostate cancer-specific mortality among men with prostate cancer. Within the Danish 'Diet, Cancer and Health' cohort, including 27 179 men, we identified 784 cases with incident prostate cancer through 2007. Each case was risk set-matched to one control. Two-thirds (n 525) of the cases had advanced disease at the time of diagnosis, and among these 170 had high-grade disease; 305 cases died (n 212 from prostate cancer) during follow-up through 2012. Plasma Se was not associated with total or advanced prostate cancer risk, but higher Se levels were associated with a lower risk of high-grade disease (HR 0·77; 95 % CI 0·64, 0·94; P=0·009). In survival analyses, a higher level of plasma Se was associated with a lower risk of all-cause (HR 0·92; 95 % CI 0·85, 1·00; P=0·04), but not prostate cancer-specific mortality. Higher levels of selenoprotein P were associated with a lower risk of high-grade disease (HR 0·85; 95 % CI 0·74, 0·97; P=0·01), but not with the risk of or mortality from advanced prostate cancer. In conclusion, levels of plasma Se and selenoprotein P were not associated with the risk of total and advanced prostate cancer, but higher levels of these two biomarkers were associated with a lower risk of high-grade disease.
In order to examine the levels of serum selenium in Europe, a collaborative study was conducted under the auspices of "The Working Group on Diet and Cancer" under "The European Organisation for Cooperation in Cancer Prevention Studies". A total of 502 serum samples was obtained from healthy, non-institutionized individuals, aged between 20 and 65 years, from 17 locations in 10 different countries in Europe. The selenium content of the samples was determined by a fluorometric method. All analyses were performed in one laboratory. Mean +/- standard deviation of the serum selenium given in microgram/l for the combined male and female data from the individual regions was: Belgium: 100 +/- 9; Denmark: Aarhus 78 +/- 15; France: Grenoble 79 +/- 15; Paris 82 +/- 11; W. Germany: Bavaria 70 +/- 10 Giessen 68 +/- 10, Heidelberg 76 +/- 9; Greece 63 +/- 14; Netherlands: 93 +/- 12; Portugal: Lissabon 102 +/- 10; Spain: Barcelona 87 +/- 14; Sweden: Göteborg 77 +/- 11, Malmö 90 +/- 14, Umeå 82 +/- 8, Uppsala 81 +/- 15; United Kingdom: Ipswich 107 +/- 13, London 109 +/- 14. None of the values represented toxic or overt deficiency levels.
The human selenium status in 10 locations of Irkutsk region (n = 216) is estimated using serum and hair selenium as biological markers. Extremely low serum selenium was typical for the inhabitants of Angara area (63-84 mcg/l). Hair selenium varied from 504 mcg/kg to 718 mcg/kg, the lowest values being found in Shelehov and Angarsk, the highest--in Karam and Mama. Low selenium concentrations were found also in the main food products: cereals--49-89 mcg/kg, meat--234-489 mcg/kg of dry weight, bread--106-180 mcg/kg of dry weight.
Human selenium status of various groups of Bashkortostan population was studied. Mean serum selenium levels for healthy adults of Ufa, Salavat, Sterlitamak were 98 +/- 11 mg/l (n = 92), 96 +/- 10 mg/l (n = 35), 103 +/- 11 mg/l (n = 20). Serum selenium concentrations for rural populations were found to be smaller: Tolbasy - 84 +/- 13 mg/l (n = 10), Chishmy - 87 +/- 10 mg/l (n = 11), Ufa suburb - 86 +/- 9 mg/l (n = 10). 7-10 years old children of Ufa demonstrated 83 +/- 11 mg Se/l serum and 11-14 years old group - 95 +/- 11 mg/l. Pregnant women serum selenium happened to decrease by 20-30% at the end of the second part of gestation and reached the values of 55-70 mg/l in small settlements. Thus epidemiological data show the possibility of potential selenium deficiency risk for rural pregnant women and 7-10 years old children in Bashkortostan.