Selenium is a trace but important mineral found in brazil nuts, meat, seafood, mushrooms, and seeds. Through its antioxidant activity, selenium helps fight the aging process, prevents disease, reduces inflammation and promotes longevity. It also helps boost the abilities of other antioxidants and protects the thyroid gland from harmful imbalances and reduces inflammation.
The selenium content of food depends on adequate amounts of selenium to be present in the soil, which often isn’t the case due to over-farming in commercial agricultural spaces. Selenium deficiency causes cognitive decline, poor immune function and decreased fertility in men. On the other hand, getting enough selenium provides important health benefits, which is why supplementation is often recommended.
1. Acts as a Powerful Antioxidant and Boosts Other Antioxidants
Oxidative stress is linked to chronic diseases, including heart disease, Alzheimer’s, cancer and more. Antioxidants like selenium fight oxidative stress by reducing free radicals. These are molecules that can damage cells and DNA and are increased by smoking, alcohol, fried foods, stress and as a natural result of aging.
Selenium also helps other antioxidants increase their effectiveness. Once antioxidants such as vitamins C and E neutralize free radicals, they require the help of peptides called glutathione and thioredoxin to regenerate their antioxidant abilities. In turn, the function of glutathione and thioredoxin depends on enzymes that are composed partly of selenium. Without adequate amounts of selenium, glutathione and thioredoxin can’t help antioxidants maintain their function and reduce oxidative stress throughout the body.
2. Protects Against Heart Disease
Studies show that taking selenium supplements helps reduce oxidative stress and lowers inflammation, which are major heart disease risk factors. The American Journal of Critical Nutrition published an analysis of 25 medical studies, which determined that a 50 percent increase in blood selenium levels is associated with a 24 percent reduction in coronary heart disease.
3. Protects Brain Function and Prevents Mental Decline
Selenium levels decline with age, while oxidative stress increases. Oxidative stress is linked to the onset and progression of neurological diseases such as Alzheimer’s disease, Parkinson’s disease, and multiple sclerosis. Research has linked Alzheimer’s disease patients with low selenium levels. Some studies suggest that selenium in food and supplements may improve memory in Alzheimer’s disease patients. In one study, older adults with mild cognitive impairment who ate just one brazil nut a day experienced better verbal fluency and improvements in other mental functions. Amazingly, brazil nuts contain 137 percent of your recommended daily intake of selenium per nut.
4. Prevents and Helps Treat Cancer
Research has shown that people who develop cancer have low levels of selenium. Selenium can help reduce DNA damage and oxidative stress, which are factors that can potentially lead to cancer. It also helps your immune system kill cancer cells. A review of 69 medical studies determined that higher selenium intakes can fight certain types of cancer, including breast, lung, colon, bladder and prostate cancer.
In one study, selenium deficient participants were administered 200 mcg of selenium a day for eight weeks. Researchers looked for changes in their immune response, and by the end of the study found that selenium boosted the activity of cancer-killing cells in the participants by 82 percent.
5. Boosts Thyroid Health
Selenium helps maintain and regulate the function of your thyroid, which is a gland in the neck that regulates metabolism by releasing a delicate balance of hormones. The thyroid gland stores selenium, and contains a higher concentration of selenium than any other tissue in the body. Selenium not only protects the thyroid from oxidative stress but also plays a critical role in the production of thyroid hormones. A study involving over 6,000 participants found that low selenium levels are linked to an increased risk of thyroid diseases such as hyperthyroidism and that increased selenium intake lowers risk levels.
6. Helps Asthmatics
Asthmatics are shown to have lower selenium levels than people without asthma. Studies demonstrate that selenium supplementation reduces symptoms of asthma, and note that it may be a useful adjunctive therapy for people taking asthma medication. It works by reducing oxidative stress in the lungs and regulating immune responses that drive allergic asthma attacks.
7. Promotes Fertility in Men
Selenium deficiency is also linked to infertility in men, as selenium helps drive the movement of sperm during conception, directly affecting the behavior of sperm moving through the vaginal canal. Adequate selenium levels enhance fertility, but too much selenium can lower one’s sperm count. Therefore, getting just the right amount of selenium is crucial.
Selenium: Getting the Right Amount
Because selenium is a trace mineral, your body requires a small amount of it. However, your body flushes selenium out its system fairly quickly due to the critical roles it plays throughout. Thus, it’s important to consistently get the amounts you need to get all the benefits of selenium, especially as you age, since selenium levels decrease with age. Adults need 55 micrograms (mcg) of selenium per day. You can meet your daily requirement through food sources of selenium, the best of which are Brazil nuts, eggs, sunflower seeds, chia seeds, liver, tuna, salmon, chicken, turkey, and mushrooms.
While selenium supplementation is shown to benefit the health of people with low selenium levels, people with adequate or high amounts of selenium should avoid additional supplementation. Doses over 400 mcg can cause toxicity. To ensure you reap the health benefits of selenium, get your selenium status checked at a doctor’s office and supplement under the guidance of a health professional if needed.