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How does selenium help fight cancer?

Cancer is the second leading cause of death worldwide, according to the World Health Organization (WHO). In fact, one in six deaths globally is due to cancer.

That being said, most types of cancer can be prevented. Often, cancer prevention comes in the form of proper nutrition, as several vitamins and minerals act as potent anti-carcinogens. Selenium, for instance, is a trace mineral found in food, soil and plants that has since been studied for its potential anti-cancer activities.

According to a recent review, high concentrations of selenium can lower cancer risk, especially that of site-specific cancers like breast cancer, lung cancer, colon cancer, bladder cancer and prostate cancer. The review, published in the Cochrane Database of Systematic Reviews, also showed that selenium can lower cancer mortality.

What is selenium?

Selenium is one of the many nutrients the body needs but cannot make on its own, which is why people have to obtain it from natural food sources. Selenium-rich foods include nuts, seafood and whole grains. (Related: Selenium and antioxidants: Health benefits of nutrient-rich Brazil nuts.)

A ubiquitous element, selenium ends up in foods when plants and animals absorb minerals from the soil. But some people also use selenium supplements to ensure that they get sufficient amounts of this trace mineral.

Due to its powerful antioxidant properties, selenium is linked to several health benefits, including improved cardiovascular functions and reduced risk of cognitive decline.

The anti-cancer activities of selenium

Selenium’s most popular health benefit comes from its anti-cancer activities. Several studies have explored selenium as a possible anti-carcinogen. For instance, a 2001 animal study on the anti-cancer activities of selenium showed that it can help prevent the spread of cancer cells in the colon, lung, liver and mammary tissues of rats. Selenium was also found to induce apoptosis, or programmed cell death, in tumor cells.

In the present review, an international team of researchers looked at 83 randomized controlled trials and 70 observational studies that compared the effects of selenium supplements with placebos. The former involved a total of 27,232 participants aged 18 years and older, while the latter included more than 2,360,000 participants aged 18 years and older.

The researchers found that supplementation with selenium in the randomized controlled trials did not lead to a reduced risk of cancer. In contrast, the observational studies showed that lower cancer risk and lower cancer mortality were directly linked to high concentrations of selenium. In particular, the data showed a reduced risk of certain cancers, such as breast, lung, colon, bladder and prostate cancer.

Selenium helps stimulate the DNA repair process

Another recent study showed that selenium can help repair deoxyribonucleic acid (DNA) damage by carcinogens. The study, published in the Journal of Cancer Prevention, also revealed that selenium can stop cell migration and invasion (metastasis), especially in cancers of the breast, colon, melanoma, liver, lung and prostate.

A carcinogen induces genetic damage when it latches onto DNA and alters its components. To combat this, an anti-carcinogen like selenium neutralizes enzymes that enable chemical carcinogens to damage DNA.

Selenium can also prevent further DNA damage and improve DNA repair capacity by boosting the protective activities of DNA repair enzymes.

According to the study, DNA repair capacity is enhanced when selenium intake is coupled with zinc, another trace mineral known for its ability to enhance immune functions. Zinc also boosts selenium’s antioxidant and chemopreventive activities.

Currently, there is no consensus among experts as to whether selenium can be utilized as a treatment for cancer. Still, extensive studies on selenium provide sufficient evidence that it can significantly reduce the risk of cancer and minimize its effects on the body. has more stories on vitamins and minerals for cancer prevention.

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