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A new study from Texas has added evidence to the case that selenium and Vitamin E may play a role in the prevention of prostate cancer. The study, “Selenium and Vitamin E: Cell Type– and Intervention-Specific Tissue Effects in Prostate Cancer” was published in the Journal of the National Cancer Institute. Headed by Dimitra Tsavachidou, it examined 39 pre-radical prostatectomy men diagnosed for a duration between three and six weeks prior to surgery. The participants were randomly assigned to one of four groups being treated with either 200 mg selenium, 400 IU Vitamin D, both nutrients or a placebo.
Using biopsy specimens, the researchers conducted follow-up tissue analysis to identify normal, stromal and tumour cells. Their analysis identifed how genes were differentially expressed according to both the treatment and cell type.
Tsavachidou’s team found that the highest number of differentially expressed genes were 63% in normal epithelial cells after selenium treatment, 66% of genes in stromal cells after Vitamin E treatment and 56% of genes in tumor cells after combination treatment.
Selenium and Vitamin E were shown to have biological effects that had an impact on specific cells and the molecular pathways, which differed among normal epithelial, stroma and cancer tissues. The statistically significant effects prompted the authors to note: “We have also identified cell type– and zone-specific tissue effects of interventions with selenium and Vitamin E that may have clinical implications.”
The findings of this small study support earlier larger trials, such as the Nutritional Prevention of Cancer Study and the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study, which reported that the same nutrients, alone or in combination, may reduce the risk of prostate cancer.
Results from another large-scale trial, Selenium and Vitamin E Cancer Prevention Trial (or SELECT), the authors reported no significant differences between the supplement or placebo groups with regards to the risk of prostate cancer. The design of SELECT, however, has been criticized by academics and industry for the supplement formulations used.
With more than 500,000 new cases of prostate cancer diagnosed each year around the world, there is still much work to do.
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