Selenium for prostate cancer prevention

Selenium was believed to prevent prostate cancer.

Selenium is an essential trace mineral required for the normal function of human body.
Selenium containing enzymes (selenoproteins) have been found to catalyze many antioxidant activities.
It is believed that one of the main reason for the occurrence of malignancy, especially of prostate glands, is the damage of the genetic components of the cells by free radicals.
Many a successful experiment and trial had been done and recorded in the late 1990s and early 2000 about the usefulness of selenium in the prevention of these malignancies with the supplementation of Se.

Selenium and prostate cancer in NPC study 1996

The NPC (Nutritional Prevention of Cancer) study on prevention of new non-melanoma skin cancers and it was found that there was no benefit of this mineral in preventing this disease.
However among the participating men who took selenium for 6½ years, there was about 60% less incidence of development of prostate malignancy than the men taking only placebo.
When the participants were followed up in 2002 it was found that men who took its supplements for more than 7½ years, there was about 52% less incidence of development of this disease than the men taking only placebo.
This encouraging result was the corner stone for conduction of SELECT.
In another study conducted by Ulrike Peters, Charles B Foster, Nilanjan Chatterjee, Arthur Schatzkin, Douglas Reding, Gerald L Andriole, E David Crawford, Stefan Sturup, Stephen J Chanock and Richard B Hayes of Fred Hutchinson Cancer Research Center, Seattle, USA and other research facilities, it was concluded that,
serum level of this mineral was not associated with overall prostate malignancy risk;
in men taking high levels of vitamin E, higher serum selenium concentration was associated with low risk;
in multivitamin users, higher serum concentration was associated with reduced risk.
Among smokers, it was found that the risk was much reduced when high serum levels are maintained.

Selenium may worsen existing prostate cancer in certain cases

In a study conducted by Dr Philip Kantoff from the Dana-Farber Cancer Institute in Boston, Massachusetts, USA and others, DNA and blood from men with localised or advanced prostate malignancy were analysed.
This analysis revealed that, on the whole, a slight increase in risk of aggressive type of malignancy was associated with higher levels of selenium.
However the results were affected by the forms of SOD2 gene present.
In patients with 'AA' gene, those with low levels of selenium were found to be 40% more likely to have aggressive prostate malignancy than persons with high serum selenium levels.
It was found that the reverse was true for the persons with 'V' form of gene.
In patients with 'V' gene, those with its low levels were found to be 33% less likely to have aggressive disease than persons with high serum selenium levels.
Hence it is advisable to think twice before taking supplements in case of existence of malignancy.

Selenium in prostate cancer prevention: SELECT trial

In order to have a comprehensively study to evaluate usefulness of vitamin E and Selenium in the prevention of malignancy, SELECT (Selenium and Vitamin E Cancer Prevention Trial) was taken up (35533 participants).
However SELECT trial showed that there was no benefit from trace mineral and vitamin E supplements in terms of risk reduction and prevention of prostate cancer.
Related selenium topics:
Health benefits.
Antioxidant functions.
Selenium for heart.
Treatment of Keshan disease.
Overdose and side effects.
Deficiency and symptoms.
Selenium for prostate cancer (current topic).

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