Selenium is a trace mineral, which means the body only requires it in very small amounts. It is naturally present in many foods and is also available as a dietary supplement.
The majority of selenium from our diet gets stored in muscle tissue, though the
Selenium is an
Selenoproteins also act as powerful antioxidants that help protect against damaging particles in the body called free radicals.
According to a
According to some research, selenoproteins are primarily responsible for many of the health benefits of selenium.
For example, one 2021 review found that selenoproteins play a key role in controlling and removing
Experts also believe that selenium protects the skin against ultraviolet (UV) oxidative stress by stimulating the selenium-dependent antioxidant enzymes glutathione peroxidase (GPx) and
Moreover, a newer study from 2020 found that increased dietary intakes of selenium are associated with longer telomeres. This study found that every 20 microgram increase in dietary selenium was associated with a 0.42% longer telomere length in participants over the age of 45.
Telomeres are “protective caps” located on the ends of our chromosomes that affect how quickly cells age. Some experts consider telomere length as an informative biomarker of aging.
For example, centenarians often appear to have higher systemic levels of selenium and iron while having lower levels of copper than other older people.
However, it is important to note that results remain conflicting and more research on the topic is needed. Some studies — such as the one referred to above — suggest that low levels of selenium may actually promote longevity.
Selenium may also play an important role in the protection against certain age-related diseases.
Although some research appears promising, there is
There is a notion that selenium may play a role in cancer prevention thanks to its ability to protect cells against DNA damage and mutations. However, the evidence around this remains conflicting.
According to a 2018
In fact, some
Selenium plays a key role in thyroid function. Some
However, according to the
Because serum selenium levels decline with age, marginal or deficient selenium concentrations may be associated with age-related
Still, more research is needed to determine if selenium supplementation can help treat or prevent age-related cognitive decline in older adults.
Overall, research remains conflicting regarding selenium supplementation and the effect of selenium on aging.
According to the 2018 review discussed above, most studies point to selenium supplementation having anti-aging properties and preventing aging-related diseases. However, more studies are needed to clarify its role.
At this time, there is no solid evidence that selenium supplementation benefits a person who is not at risk for deficiency.
A selenium deficiency is rare in the United States because of the selenium-rich soil found throughout North America.
Still, certain groups are at risk for selenium deficiency, including:
- people living with HIV
- people with kidney failure requiring hemodialysis
- people who live in low-selenium regions, including some European countries, Russia, and China.
The risk is further increased for people living in low-selenium areas who follow a vegetarian or vegan diet.
Selenium deficiency can weaken cells’ ability to grow and divide, which can contribute to aging. It can also lead to delayed wound healing, cataract development, and loss of color.
Most adults need
Since the human body does not generate its own selenium, it is essential to get optimal amounts from the diet, in order for it to benefit overall health.
Thankfully, selenium is found in a wide variety of foods that can be easily incorporated into a person’s diet.
Because selenium is found in soil, its levels in food will be based on how much selenium was in the soil where the food was grown.
Brazil nuts, seafood, and organ meats are among the highest dietary sources of selenium. For example, one ounce of brazil nuts has
Other good dietary sources of selenium include:
- yellowfin tuna
- cottage cheese
- brown rice
- boiled eggs
- whole wheat bread
If a person consistently exceeds the recommended upper limit of
One of the first signs of excessive selenium intake is a garlic smell on the breath and a metallic taste in the mouth.
- hair and nail loss or brittleness
- skin lesions
- mottled or decaying teeth
Taking megadoses of selenium can lead to
Selenium is an important mineral that is needed for many important functions within the body. There is also limited evidence that it may provide several different health benefits.
Selenoproteins are powerful antioxidants that can help protect against damage caused by free radicals that lead to aging and age-related health conditions.
At this time, there is no evidence that selenium supplements can slow or prevent aging. However, it is important to include optimal amounts of selenium in the diet because it does play a role in neutralizing free radicals and reducing inflammation, both of which can contribute to premature aging.
If you believe you have a selenium deficiency or are considering taking selenium supplements, be sure to speak with your healthcare provider.