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Selenium is an essential mineral, meaning your body can’t make it and has to get it through your diet. And research shows that low levels of selenium are associated with higher levels of inflammatory compounds.
That said, by itself, selenium doesn’t offer much benefit. But when selenium teams up with other compounds — in particular some proteins or a few specific enzymes — it has powerful anti-inflammatory effects, as well as other far-reaching health benefits. For example, when paired with enzymes selenium helps the body break down harmful free radicals (aka compounds that encourage inflammation).
Also, because of its antioxidant powers, selenium also helps combat the negative effects of stress — experts think that if you are selenium-deficient your body’s built-in antioxidant protection against the physical effects of stress may be impaired. However, research shows there is a tipping point: too much selenium may increase harmful free radicals.
Did You Know? Toxicologists have long known that adequate selenium intake helps prevent mercury toxicity.
As a result of, or in addition to, the anti-inflammatory perks of selenium, there’s also research that shows selenium can help maintain brain function as you age, fight infections (including possibly preventing viruses from mutating into something more harmful), and lower your risk of some cancers.
This article is part of our ongoing series Eating For Your Mental Health.
4 Key Health Benefits of Selenium
Protects against depression
Falling short on selenium may increase your risk of developing depression. Not only is selenium thought to play a role in producing some of those feel-good hormones, but it is also is crucial for your body to make thyroid hormones — and out-of-balance thyroid hormones impact your mood. Other research is mixed: some studies show that selenium supplements help with depression and others say no such thing exists.
Keeps aging minds sharp
In one study of approximately 1,400 older men and women, French researchers found that cognitive function closely paralleled selenium levels, and the greatest decline in cognitive function was among those with the lowest blood levels of selenium. Other (older) research found that poor test scores in elderly adults were linked with low selenium levels.
Fights viral infections
Almost 20 years ago, researchers reported that selenium supplements were beneficial in the treatment of HIV (human immunodeficiency virus) infection, and a 2020 research review suggested that they may also be beneficial for COVID-19 infection. As the researchers noted, “The significant body of evidence from human, animal, and cell culture studies indicates that [selenium] status is an important factor in response to viral infections…including respiratory virus infections.”
Protects against (some) cancers
Research has somewhat consistently found that high selenium levels have a protective effect against cancer. Drill down into the specifics and you’ll find that some show selenium lowers the risk of developing colorectal cancer, while others only have significant findings for breast, lung, esophageal, stomach, and/or prostate cancer.
How Much Selenium Do You Need?
Most Americans get sufficient amounts of selenium (the daily average from food is just shy of 109 mcg), according to national diet surveys. However, globally, as many as 1 in 7 may be selenium deficient.
The majority of selenium is stored in our muscles. Perhaps this is why we naturally lose selenium as we age. (This is also potentially why selenium may be associated with age-related cognitive decline.) Still, the daily recommendation for adults from 19 years old to 51-plus is the same: 55 micrograms per day, says the National Institutes of Health.
Did you know? Selenium was recognized as essential for people in 1957—relatively recently as nutrition research goes.
Do You Need A Selenium Supplement?
Your daily cap — aka the tolerable upper intake level (UL) — is 400 micrograms a day. So if a supplement is something you are interested in considering: aim to cap your supplement amount at 200 to 300 mcg daily (remember, you get about 100 mcg from food each day). That said, the research isn’t conclusive yet as to whether or not supplementing with selenium is needed, particularly as it relates to cancer.
The Best Foods For Boosting The Selenium In Your Diet
Brazil nuts, seafood (tuna, halibut, sardines, shrimp), and organ meats are the richest food sources of selenium. Beef, turkey, and chicken are also good ways to get selenium, as are grains. Selenium amounts in food, however, depend on the selenium content of the soils in which it is grown—whether you’re eating it directly or it’s going into the food the animal you’re eating, eats.
|Brazil nuts, 6 to 8||554mcg, 989% DV|
|Tuna, yellowfin, 3 ounces||92mcg, 167% DV|
|Halibut, 3 ounces||47mcg, 85% DV|
|Sardines, 3 ounces||45mcg, 82% DV|
|Ham, 3 ounces||42mcg, 76% DV|
|Beef steak, 3 ounces||33mcg, 60% DV|
|Turkey, 3 ounces||31mcg, 56% DV|
|Brown rice, 1 cup||19mcg, 35% DV|
|Whole-wheat bread, 1 slice||13mcg, 24%DV|
|Oatmeal, 1 cup cooked||13mcg, 24%DV|