Potential Benefits
Selenium is indeed essential for optimal body function and health, and it may play a role in other important aspects of our health as well. Here are some areas of particular interest:Cancer protection: Selenium has been associated with lowered risk of some cancers, which may be due to its antioxidant activity, helping reduce oxidative stress, boost immunity, and fight cancer cells. One review of 69 clinical studies found that higher levels of selenium in the blood were associated with reduced risk of breast cancer, lung cancer, esophageal cancer, gastric cancer, and prostate cancer.
Heart health: As an antioxidant, selenium may help reduce oxidative stress and inflammation, and may help decrease the risk of heart disease. Low levels of selenium have been tied to increased risk of heart disease and higher levels have been shown to reduce risk of heart disease. However, these were observational studies, so more research is needed.
Brain health: Lower blood levels of selenium have been linked with cognitive decline (including dementia, memory loss, and Alzheimer’s disease). Studies have shown that consuming sufficient levels of antioxidants, such as selenium, from the diet can help reduce risk of developing Alzheimer’s disease as well as improving mental function. The Mediterranean diet, high in selenium-rich foods, is one such dietary source.
Food Sources
Dietary selenium can be found in plant foods (nuts, whole grains) and in animal sources (seafood, beef, poultry, and dairy). In plant foods, the amount of selenium present varies due to the selenium content of the soil in which they are grown, which can vary widely. For example, one study found that selenium levels in Brazil nuts can vary due to their growing region. In one region, one nut provided as much as 288 percent DV of selenium, while others provided 11 percent DV. Consuming a variety of foods is one way to protect adequate intake.How much Do We Need?
Considered a trace mineral, we need just a very small amount of selenium from our diets each day. Because it plays such an active role in our bodily functions, it’s important to consume it regularly. The recommended DV (DV=Daily Value, based on 2,000 calories/day) of selenium increases with age and adults age 18 years and older need 55 micrograms per day.Supplements
Research from the National Institutes of Health has shown that most people get, on average, more than 100 mcg of selenium from their diets alone each day, so unless you have a condition that puts you at risk for not meeting the daily recommendation, supplementing should not be necessary. Selenium deficiency is rare and it may take years to develop. People with low levels of selenium may use supplements to help prevent or treat complications like muscle disorders, thyroid disorders, heart disease, and immune dysfunction.Other groups who may have low selenium levels may be those with poor dietary intake, those in locations with low levels of selenium in the soil in which their food is grown, and those with chronic diarrhea, Crohn’s disease or other inflammatory bowel disease, people with HIV, and people undergoing kidney dialysis.
Selenium may can be found in multivitamins and other dietary supplements, which may contain one of two different forms of the mineral: selenomethionine and sodium selenate. The upper limit for safe selenium dosage per day is 400 mcg for adults. When selenium is sourced from food, this limit is not likely to be met. However, an overdose in a concentrated supplement amount can have potentially serious negative health outcomes, including kidney failure, heart failure and death.
Check with your health care provider to determine whether a selenium supplement is right for you, as it may interact with some medications, such as antacids, chemotherapy drugs, statins and birth control pills. As with any dietary supplement, be sure to purchase them from a reputable source.
