Cervical dysplasia is a potentially pre-cancerous condition and in many cases can resolve on its own, but in others, can progress to more severe dysplasia and even cervical cancer. The likelihood of regression of mild dysplasia, called cervical intraepithelial neoplasia grade 1 (CIN1), is 60%. The likelihood of progression to cervical cancer if it does not regress or is not treated, is 30-50%. The main risk factors for CIN1 are the human papilloma virus (HPV), HIV and nicotine. There are now studies that have shown that increased inflammatory cytokines and oxidation may result in higher concentrations of HPV in the cervicovaginal secretions which then make the cervical cells more vulnerable.
Several studies have shown a potential for select antioxidants in the treatment of CIN including vitamin C, vitamin A, beta carotene and selenium. While not all studies are consistent or conclusive, there has been an inverse relationship seen between serum selenium levels and CIN or cervical cancer. In addition, in one study, the tissue concentrations of selenium are significantly lower in cervical cancer tissues compared to non-cervical cancer tissues.
In the current randomized, double-blind clinical trial, 58 Iranian women ages 18-55 with biopsy proven CIN 1 were included. Women were randomized to take 200 mcg selenium per day or placebo for 6 months. The selenium group had regression of their CIN1 compared with the placebo group. In addition, those in the selenium group had improvements in metabolic profiles compared with placebo including decreases in fasting glucose and insulin, improved insulin resistance, increased total antioxidant capacity, increased HDL levels and decreased triglycerides levels.
Commentary: To my knowledge, this is the first randomized controlled clinical trial using selenium for CIN1. Other studies have been done but not a clinical trial. In a study by Kim et al, (Kim S, Kim J, Ko Y, et al. Changes in lipid peroxidation and antioxidant trace elements in serum of women with cervical intraepithelial neoplasia and invasive cancer. Nutr Cancer 2003;47:126-130) selenium levels were significantly lower in women with CIN or cervical cancer. In another study, a combination of 50 mg selenium, 60 mg vitamin C, 10 mg vitamin E and 303 mg vitamin A significantly lowered levels of apoptosis and lipid peroxides in women with cervical cancer after receiving radiotherapy compared with non-users of the antioxidant combination. (Ismail M, Amer A, Wahba O, et al. Effect of antioxidants on markers of apoptosis in postoperative radiotherapy of cancer cervix. Gulf J Oncolog 2010;7:8-13.)
Unfortunately, this study did not address the HPV effects of selenium. It would ultimately be clinically useful to know if selenium caused resolution of high risk strains of HPV and in particular type 16 and/or 18.
Reference: Karamali M, Nourgostar S, Zamani A, et al. The favourable effects of long-term selenium supplementation on regression of cervical tissues and metabolic profiles of patients with cervical intraepithelial neoplasia: a randomised, double-blind, placebo-controlled trial. Brit J Nurtition 2015;114:2039-2045.