Selenium is an essential mineral found naturally in many foods, available as a nutritional supplement, and helps reduce the risk of some types of cancer – a link attributed to selenium’s ability to reduce DNA damage and oxidative stress, boost the immune system and destroy cancer cells.
Oxidative stress is described as an imbalance of unstable atoms, called free radicals, and compounds called antioxidants in the body, which can lead to cell and tissue damage.
A review of 69 studies involving more than 350,000 people found that a higher blood level of selenium was associated with a lower risk of developing certain types of cancer, including breast, lung, colon and prostate cancers.
It is important to note that this effect was only associated with selenium, which is obtained through foods, not supplements.
Eating a diet rich in selenium may help keep your heart healthy, as low selenium levels have been linked to an increased risk of heart disease.
In an analysis of 25 observational studies, a 50% increase in blood selenium levels was associated with a 24% reduction in heart disease risk.
Selenium may also reduce markers of inflammation in your body – one of the main risk factors for heart disease.
For example, a review of 16 controlled studies, including more than 433,000 people with heart disease, showed that taking selenium supplements reduced levels of C-reactive protein (CRP).
This indicates that selenium may help reduce the risk of heart disease, by reducing inflammation and oxidative stress in your body.
Selenium has also shown promising results in reducing the risk of developing Alzheimer’s disease, a progressive, irreversible brain disorder that destroys memory and thinking skills slowly.
Oxidative stress is thought to play a role in both the onset and development of neurodegenerative diseases, such as Parkinson’s disease, multiple sclerosis and Alzheimer’s disease.
Several studies have also shown that Alzheimer’s patients have low levels of selenium in the blood.
In addition, some studies have found that antioxidants in both foods and supplements may improve memory in Alzheimer’s patients.
What’s more, one small study found that taking one selenium-rich Brazilian nut supplement daily improved verbal fluency and other mental functions in patients with mild cognitive impairment.
A Mediterranean diet, rich in foods high in selenium, such as seafood and nuts, was associated with a reduced risk of Alzheimer’s disease.