#DoesItWorkSummary: Selenium For Prevention Of Cancer

Background: This #DoesItWorkSummary is based on the findings of a Cochrane Systematic Review published in January 2018 [1]. Selenium is an element that is normally taken with food and is essential for healthy metabolism in small amounts (belonging in this way to the group of micronutrients). It is found in a variety of foods from animal and plant origin, with Brazil nuts and seafood being especially rich sources [2]. Although being an important micronutrient, at higher amounts selenium has toxic action [3], making the dose of intake very important for beneficial health effects (optimally, the intake should be high enough to prevent deficiency, but not so high that it would result in toxicity). There have been some indications that selenium might act as cancer-preventive agent, possibly through antioxidant effects mediated by proteins that need selenium for their functions (selenoproteins) [4]. To get an overview of scientifically documented effectiveness of selenium in preventing cancer, evaluation of the published scientific literature was done.

Findings: Analyzed were 10 randomized controlled trials (representing high-quality evidence) in which people were randomly assigned to receive selenium supplements or placebo, and 70 observational studies (representing low-quality evidence) in which people were followed over time to determine whether their selenium exposure status was associated with changed risk of cancer [1].

All of the 10 high‐quality randomized trials reported no effect of selenium on reducing cancer risk. Moreover, some of the high-quality trials unexpectedly indicated that selenium may increase risks of high‐grade prostate cancer, dermatitis, hair loss, and diabetes type 2.

The 70 observational studies (low-quality evidence) yielded overall inconsistent results. Nevertheless, when all data were pooled together lower incidence of cancer was observed in the people belonging to the highest category of selenium exposure compared with the lowest (but there was no dose-response relation supporting this observation).

Taken together, the currently existing scientific evidence does not support that selenium supplementation has cancer-preventive effect.

Future research might be needed to specifically explore if selenium may affect the risk of cancer in individuals with specific genetic backgrounds or specific nutritional status, and to evaluate if different chemical forms of selenium may differently affect cancer risk.



1          Vinceti, M., Filippini, T., Del Giovane, C., Dennert, G., Zwahlen, M., Brinkman, M., Zeegers, M.P., Horneber, M., D’Amico, R. and Crespi, C.M. (2018) Selenium for Preventing Cancer. Cochrane Database of Systematic Reviews, John Wiley & Sons, Ltd. https://doi.org/10.1002/14651858.CD005195.pub4.

2          Barclay, M.N.I., MacPherson, A. and Dixon, J. (1995) Selenium Content of a Range of UK Foods. Journal of Food Composition and Analysis, Academic Press, 8, 307–318. https://doi.org/10.1006/JFCA.1995.1025.

3          Tinggi, U. (2003) Essentiality and Toxicity of Selenium and Its Status in Australia: A Review. Toxicology Letters, Elsevier, 137, 103–110. https://doi.org/10.1016/S0378-4274(02)00384-3.

4          Diwadkar-Navsariwala, V. and Diamond, A.M. (2004) The Link between Selenium and Chemoprevention: A Case for Selenoproteins. The Journal of Nutrition, Oxford University Press, 134, 2899–2902. https://doi.org/10.1093/jn/134.11.2899.


Keywords: #DoesItWorkSummary, selenium, systematic review, clinical trials, selenoproteins, prevention of cancer.

SelenoLife participa da 17º Edição da BMOS

Welcome to our homepage for the 17th BMOS – Brazilian Meeting on Organic Synthesis. We wish to invite you to take part in this exciting meeting which will bring together the very best in Brazilian Organic Synthesis and colleagues from all over the world.

The BMOS has grown from a modest beginning and now is one of the most notable events in the Brazilian Chemical Society. The attendance has grown steadily and our last meeting held in the city of Búzios (Rio de Janeiro state) had an attendance of approximately five hundred participants, including an expressive number of chemists from other South American countries, such as Argentina, Chile and Uruguay, and Europe as well.

The 17th BMOS will be held in Salvador, the capital city of Bahia, a state known for its natural wonders, welcoming people, and deeply-rooted African cultural influences. The rhythm of Capoeira – a Brazilian dance-like martial art –, the aromas and flavors of local delicacies, the religious syncretism and cultural melting pot are only a few samples of the joie-de-vivre of a people surrounded by natural beauty and who really understand the meaning of the word “alive”. The city is also home to one of the liveliest and most popular Carnival festivities in the country. Brasil’s first capital city also has an important historical center, recognized as a UNESCO World Heritage Site: the Pelourinho, featuring Brazilian Baroque churches and age-old mansions. In addition to these natural beauties and cultural charms, a thriving industry and a petrochemical hub are based in this state, making Bahia an excellent location for the 17th BMOS.

The conference will take place in an excellent location which will permit substantial and informal interaction between the invited speakers and the members of the audience. As usual, the poster sessions will be another highlight, and will allow extensive contact with students and professors. We know you will really enjoy yourself both scientifically and socially, so come and join us at the next BMOS.

Mauricio M. Victor and Silvio D. Cunha

General secretaries