Cancer selenium levels

Selenium, an essential micronutrient for plants, animals and microorganisms, has a direct impact on human health and environmental safety. Thus, Se supplementation of populations with low or deficient Se intakes may improve health, and supplementation of Se to populations with adequate intakes may reduce the risk of cancer. Selenium levels in the body are relevant for protection against chronic degenerative, neurological or neoplastic diseases. 

There is considerable evidence to suggest that selenium compounds are anticarcinogens. For one thing, tests with laboratory animals show that the incidence and size of malignant tumors are reduced when a solution containing Na2Se03 is injected at the part per million level. Beyond that evidence, statistical studies show an inverse correlation between selenium levels in the soil and the incidence of certain types of cancer. 

Epidemiological studies in humans do not suggest an association between excess exposure to selenium and cancer." Low levels of intake, however, have been associated with an increased risk of developing many kinds of cancers. With the exception of selenium sulfide, most animal studies have shown that selenium compounds inhibit tumorigenesis." High doses of selenium sulfide administered by gavage caused liver tumors in rats and lung... 

Garland M, MorrisJS, Stampfer MJ, et al, Prospective study of toenail selenium level and cancer among women. J Natl Cancer Inst 1995 87 473-475. 

Selenium levels in the diet and blood have been shown to be inversely correlated with human cancer mortality (Shamnberger,... 

Studies of laboratory animals and people show that most selenium compounds probably do not cause cancer. In fact, studies of cancer in humans suggest that lower-than-normal selenium levels in the diet might increase the risk of cancer. But levels of selenium in the diet that are much higher than normal have not been shown to reduce the risk of cancer in humans. Taking selenium so that your daily amount is greater than that required may just increase your risk of selenium poisoning. 

Supporting evidence for an antiprostate cancer effect of selenium was obtained for a nested case-control design within the Health Professional Follow-up study (Yoshizawa et al. 1998), which found that higher prediagnostic selenium levels were associated with reduced prostate cancer incidence. This study included 33,737 male health professionals aged 40-75 years who provided toenail clippings in 1987. 

Low serum selenium levels have been associated with an increased incidence of cancer in some prospective epidemiological studies (Salonen et al. 1984, 1985 Willet et al. 1983). In the United States, Willet et al. (1983) found that the risk of cancer for subjects in the lowest quintile (fifth) of serum... 

Although the age-specific risk of fatal cancers in the two populations cannot be calculated from the data reported, the overall incidence of cancer in the 4-year Finnish study was less than half that in the 5-year U.S. study. In addition, other prospective studies of Americans have found no correlation between fatal cancer and blood selenium concentrations (Coates et al. 1988). Thus, one cannot predict relative cancer risks with serum selenium levels in one population based on data from another population. 

A 9-year prospective follow-up study was conducted by Virtamo et al. (1987) on a group of men in Finland. At the beginning of the study, blood samples were taken as part of a study of coronary heart disease and other atherosclerotic diseases. Cancer data were collected from central registries for the years 1976 through 1983. The results indicated no association between low serum selenium levels (<0.045 mg selenium/L) and an increased risk of cancer. Evidence suggests that combined dietary deficiencies of vitamin E and selenium may be associated with increased cancer risk (Salonen et al. 

Chakraborty S, Ghosh R, Chatterjee M. 1995. Relation between human selenium levels and epidemiology of cancer in different districts of West Bengal, India [Abstract], Anticancer Res 15(5A) 1651-1652. 

Hojo Y. 1981a. Subject groups high and low in urinary selenium levels Workers exposed to heavy metals and patients with cancer and epilepsy. Bull Environ Contam Toxicol 26 466-471. 

Ip C, Hayes C. 1989. Tissue selenium levels in selenium-supplemented rats and their relevance in mammary cancer protection. Carcinogenesis 10(5) 921-925. 

Ip C, Lisk DJ, Ganther H, et al. 1997. Triphenylselenonium and diphenylselenide in cancer chemoprevention Comparative studies of anticarcinogenic efficacy, tissue selenium levels and excretion profile. Anticancer Res 17 3195-3200. 

Kallistratos G, Evangelou A, Seferiadis K, et al. 1985. Selenium and haemodialysis Serum selenium levels in healthy persons, non-cancer and cancer patients with chronic renal failure. Nephron 41 217-222. 

Ma J, Stampfer MJ, Morris JS, et al. 1995. Toenail selenium level and lung cancer among men and women in a high seleniferous region of the USA [Abstract], Am J Epidemiol 141(10) S68. 

Yoshizawa K, Willett WC, Morris SJ, et al. 1998. Study of prediagnostic selenium level in toenails and the risk of advanced prostate cancer. J Natl Cancer Inst 90(16) 1219-1224. 

Van Den Brandt PA, Goldbohm RA, VAtiT Veer P, Bode P, Dorant E, Hermus, etal. (1993) A prospective study of toenail selenium levels and risk of gastrointestinal cancer. J Natl Cancer Inst 85 224-229. 

Yu SY, Chu YJ, Gong XL, et al. (1985) Regional variability of cancer mortality incidence and its relation to selenium levels in China. Biol. Trace Elem Res 7 20-29. 

Lipsky, K., Zigeuner, R., Zischka, M., Schips, L., Pummer, K., Rehak, R and Hubmer, G., Selenium levels of patients with newly diagnosed prostate cancer compared with control group. Urology, 63, 912-916 (2004). 

This is due to nitrogen s ability to form strong tt bonds whereas heavier group 5A elements do not form strong tt bonds. Therefore, P2, AS2, and Sb2 do not form since two tt bonds are required to form these diatomic substances. 3. There are medical studies that have shown an inverse relationship between the incidence of cancer and the selenium levels in soil. The foods grown in these soils and eventually digested are assumed to somehow furnish protection from cancer. Selenium is also involved in the activity of vitamin E and certain enzymes in the human body. In addition, selenium deficiency has been linked... 

Several supplementation and epidemiological case-control studies have suggested a possible link between increased selenium intakes or status and protection against certain cancers. First, in intercountry comparisons and studies comparing different regions of the United States having different soil selenium levels, there was a consistent correlation between lower selenium levels and higher risk of cancer. A study of 34,000 male health professionals in the eastern United States... 

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