Selenium deficiency, especially as manifested in low circulating levels of selenoprotein P, is associated significantly with an increased risk of colorectal cancer incidence and mortality [Pal 2024; Brezina 2025]. SELENOP is a selenium-dependent glycoprotein that is the primary transporter of selenium to the tissues and organs. SELENOP also acts to reduce oxidative stress and systemic inflammation [Schöttker 2024; Brezina 2025].
In the Colorectal Cancer Study of Austria (CORSA Study), researchers analyzed data from 519 participants (n = 153 tumor-free controls, n = 255 patients with adenomas, and n = 111 patients with colorectal cancer). The median age of the study participants was 65 years. Nearly two-thirds of the study participants were male. The study participants’ median plasma selenium concentration was a very low 65.7 mcg/L. Their median SELENOP concentration was also low: 2.7 mg/L. During a median follow-up period of 5,424 days (almost 15 years), there were 210 deaths (40 %) [Brezina 2025].
SELENOP Concentrations and Mortality in the CORSA Study
In the CORSA Study with its 15-year follow-up period and the relatively high age of the study participants, the following findings are especially interesting [Brezina 2025]:
- The data showed a shorter life expectancy for patients with colorectal cancers compared to the life expectancy for patients with adenomas or controls.
- SELENOP concentrations showed an inverse association with mortality in all groups: controls, adenomas, colorectal cancers.
- Selenium and SELENOP concentrations above the median values were associated with better survival in all three groups.
- SELENOP deficiency was the single most useful parameter for prognosis.
Agreement with Other Selenium and Colorectal Cancer Studies
The Esther Study
The CORSA Study results reinforce the conclusions of a prospective observational study of older German adults. The Esther Study showed that SELENOP deficiency is significantly associated with all-cause mortality and with mortality caused by cancer, cardiovascular disease, and respiratory and gastrointestinal diseases [Schöttker 2024].
The EPIC Study
In the European Prospective Investigation into Cancer and Nutrition (EPIC) Study, researchers reported an increased risk of colorectal cancers in study participants with low SELENOP or selenium concentrations [Hughes 2015].
The Bonelli Study
Adenomatous polyps are precursors to many of the cancers that develop in the colon and the rectum. Patients who have undergone a polypectomy are at increased risk of adenoma recurrence.
In an Italian study, researchers randomly assigned 411 colonoscopy patients to receive an antioxidant cocktail consisting of 200 mcg selenium, 30 mg zinc, 2 mg vitamin A, 180 mg vitamin C, and 30 mg vitamin E or a placebo daily for five years. Of the 411 patients, 330 had a follow-up colonoscopy (164 in the intervention group and 166 in the placebo group).
The 15-year cumulative incidence of adenoma recurrence was 48.3% in the intervention group and 64.5% in the placebo group. Thus, there was a statistically significant reduction of the risk of adenoma recurrence in the intervention group compared to the placebo group. The risk reduction was similar for small tubular adenomas and advanced adenomas [Bonelli 2013].
Conclusions: Lower SELENOP and Risk of Colorectal Cancers
The data from the above summarized studies indicate that there is increased mortality risk with low SELENOP status at the time of cancer diagnosis.
It is important to avoid insufficient selenium intake and selenium deficiency.
In the KiSel-10 study of elderly Swedish citizens, daily supplementation with 200 mcg of selenium from a high-selenium yeast preparation induced higher levels of SELENOP. The improved SELENOP expression facilitated systemic selenium bioavailability and resulted in the positive health effects: reduced telomere attrition, reduced systemic inflammation, reduced mortality, and improved quality of life [Alehagen 2024].
Selenoprotein P deficiency needs to be diagnosed and corrected by supplementation in regions of the world with selenium-poor soils and selenium-poor foodstuffs.
Sources
Alehagen U et al. Selenoprotein P increases upon selenium and coenzyme Q10 supplementation and is associated with telomere length, quality of life and reduced inflammation and mortality. Free Radic Biol Med. 2024 Sep;222:403-413
Bonelli L et al. Antioxidant supplement and long-term reduction of recurrent adenomas of the large bowel. A double-blind randomized trial. J Gastroenterol. 2013 Jun;48(6):698-705.
Brezina S et al. Colorectal cancer mortality is associated with low selenoprotein P status at diagnosis. Redox Biology. 2025;84:103701.
Hughes DJ et al. Selenium status is associated with colorectal cancer risk in the European prospective investigation of cancer and nutrition cohort. Int J Cancer. 2015 Mar 1;136(5):1149-61.
Pal A et al. Selenium levels in colorectal cancer: A systematic review and meta-analysis of serum, plasma, and colorectal specimens. J Trace Elem Med Biol. 2024 Jul;84:127429.
Schöttker B et al. Strong associations of serum selenoprotein P with all-cause mortality and mortality due to cancer, cardiovascular, respiratory and gastrointestinal diseases in older German adults. Eur J Epidemiol. 2024 Feb;39(2):121-136.
The information presented in this review article is not intended as medical advice. It should not be used as such.