Research linking selenium to prostate cancer risk has been conflicting, with early research showing protection and later supplementation studies showing no protective effect and possibly slight increased risk. A small new study working to understand the action of selenium in the prostate shows that taking supplements of selenium for only five weeks changes the expression of genes involved in cell invasion and immune response, which could play a role in cancer progression.
The study was funded by the World Cancer Research Fund.
For this study, researchers randomized 23 men into two groups. The men were all at high risk for prostate cancer or diagnosed with prostate cancer, and were in the process of having biopsies. One group of participants receive 300 µg of selenium per day in the form of selenized yeast while the other group took a placebo for five weeks. Prostate biopsies were collected before and after the intervention and whole-genome expression profiles were analyzed in non-cancerous prostate tissue.
The genome analysis – completed on 15 of the men – found that the selenium group did measure higher blood levels of the mineral after the five week period. Compared to the placebo group, the selenium group was associated with changes to the expression of genes involved in signaling pathways related to inflammation, cellular immune response and cellular growth, proliferation and development.
It was also found that selenium changed the expression of genes involved with having an anti-inflammatory effect in the prostate and wound healing.
The changes in genes expressed relate to cancer progression, as opposed to development, the authors say. The findings suggest a preventive effect of selenium on prostate cancer progression. More studies are needed.
Sources: Kok, Dieuwertje E.G. et al. “A Short-Term Intervention With Selenium Affects Expression Of Genes Implicated In The Epithelial-To-Mesenchymal Transition In The Prostate”. OncoTarget, Impact Journals, 2017.