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.
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.
Selenium may also play an important role in the protection against certain age-related diseases.
Heart disease
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.
Cancer
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.
Thyroid disease
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.
Cognitive decline
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.
Source: Medical News Today
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