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Selenium and Breast Cancer Prognosis

Updated: Jan 17, 2023

A recent study examined the role that selenium status played in the prognosis of breast cancer. This study looked at the level of selenium in a woman’s blood at the time of her diagnosis of breast cancer and correlated this with overall survival and risk of cancer recurrence. Selenium levels were determined using three blood-based biomarkers: serum selenium, selenoprotein-P (SELENOP), and glutathione peroxidase 3 (GPx3).

Selenium’s essential importance is due to it’s role in the production of antioxidants, often referred to as redox. Antioxidants are molecules which are used to help the body get rid of excess free radicals. Free radicals are molecules missing an electron and can cause damage by stealing electrons from tissue. Antioxidants, on the other hand, are considered electron donors, and can provide the free radicals with the needed electrons without having to steal from the tissues.

This study, which followed nearly 2000 women reported that all three biomarkers inversely correlated with mortality. Those women with the lowest levels of all three biomarkers had the highest mortality risk with an overall survival probability of roughly 50% after 8 years. Additionally, it was found that low levels of GPx3 activity was associated with increase risk of recurrences.

In the US selenium deficiency is thankfully rare, although estimates suggest that up to a billion people worldwide may be deficient. The RDA in the US is 50mcg, with pregnant and lactating women requiring 60-70mcg per day. A recommended upper limit intake of 400mcg is suggested. Interesting to point out that pregnant and lactating women are thought to be those most at risk for selenium deficiency in the US. This is also the demographic at highest risk for developing an aggressive breast cancer.

I’ve started adding a selenium analysis to the labs I recommend for all my breast cancer patients and think of this as one more risk factor that can be eliminated. I also think it’s a good idea for women to run a selenium analysis as part of their annual laboratory assessment.

Seafoods, organ meats, and Brazil nuts are all good sources of selenium. Soil-grown vegetables are also typically a good source as most soils in the US are rich in selenium.

This study can be found HERE


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