Selenium is an essential trace mineral that is important for many functions in the body. Recent research suggests that selenium has anti-aging properties and may even protect against age-associated disease. In this Honest Nutrition feature, we explore we explore the latest research to investigate the role of selenium in aging.
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 thyroidTrusted Source is the organ with the highest concentration.
Selenium is an important componentTrusted Source of enzymes and proteins — known as selenoproteins — that play a key role in reproduction, thyroid hormone metabolism, and DNA synthesis.
Selenoproteins also act as powerful antioxidants that help protect against damaging particles in the body called free radicals.
Free radicalsTrusted Source are unstable atoms produced naturally in the body as a byproduct of normal functions within the body. They cause damage to cell membranes and DNA. Over time, this can lead to inflammation, premature skin aging, and a host of age-associated diseases.
Anti-aging benefits of selenium
Biological agingTrusted Source is a complex process that involves molecular damage, metabolic imbalance, immune system changes, and increased susceptibility to environmental stressors and disease.
According to a reviewTrusted Source from 2018, selenium can fight aging and prevent age-related health issues, such as tumors, cardiovascular disease, and neuropsychiatric disorders. Some researchers also believe that selenium can reduce chronic inflammationTrusted Source, which is closely related to aging.
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 misfolded proteinsTrusted Source, which accumulate as we age. Specialists note that the accumulation of misfolded proteins is a common characteristic of aging and age-related diseases, including type 2 diabetes and Alzheimer’s disease.
Experts also believe that selenium protects the skin against ultraviolet (UV) oxidative stress by stimulating the selenium-dependent antioxidant enzymes glutathione peroxidase (GPx) and thioredoxin reductaseTrusted Source (TDR). TDR is located in the plasma membrane of epidermal keratinocytes. This may potentially combat aging skin caused by UV exposure.
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.
ResearchersTrusted Source also believe that higher levels of selenium are associated with longevity. The all-cause mortality of older adults with low selenium levels is signiﬁcantly higher than that of the elderly with a high level of selenium.
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.
Other health benefits
Selenium may also play an important role in the protection against certain age-related diseases.
One meta-analysisTrusted Source found that people with lower selenium levels are at a higher risk of coronary heart disease. In contrast, a review Trusted Sourceof trials that used only selenium supplementation for the primary prevention of heart disease found no statistically significant effects of selenium on both fatal and nonfatal cardiovascular events.
Although some research appears promising, there is not enough evidenceTrusted Source to support the routine use of selenium supplements, especially in those who are obtaining enough from food to prevent heart disease at this time.
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 reviewTrusted Source of 83 studies, there is no solid research to suggest selenium from diet or supplements prevents cancer in humans.
In fact, some trialsTrusted Source suggest that selenium supplementation may increase the risk of non-melanoma skin cancer and type 2 diabetes.
Selenium plays a key role in thyroid function. Some studiesTrusted Source suggest that having optimal selenium levels can protect against thyroid disease and preserve overall health.
However, according to the Office of Dietary SupplementsTrusted Source, additional research is needed to determine whether selenium supplements can treat or prevent thyroid disease.
Because serum selenium levels decline with age, marginal or deficient selenium concentrations may be associated with age-related declines in brain functionTrusted Source. Experts believe this might be due to selenium’s antioxidant properties.
Still, more research is needed to determine if selenium supplementation can help treat or prevent age-related cognitive decline in older adults.
Should I take a selenium supplement?
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.