Selenium is an essential trace mineral that plays a unique and important role in a wide range of biological functions. Your body can’t make selenium, so it’s important to get it from your food. It is a major component in more than two dozen proteins that play important roles in a variety of functions, including thyroid hormone metabolism, and DNA synthesis and reproduction.first
Selenium is also an antioxidant, which means it helps protect the body against free radicals and reactive oxygen species (ROS). It exists in two forms: inorganic and organic, both of which are found in food sources – including the organic form in animal tissues.
Like most compounds, your body needs an optimal amount of selenium, which means more is not better. There is some evidence to suggest that high serum concentrations may adversely affect glycemic control.2 This means that people with Type 2 diabetes or at risk for Type 2 diabetes should have their serum levels measured before considering taking a selenium supplement.
When your body has optimal levels of selenium, it can help improve biological function, which in turn has a positive impact on fighting heart disease, cognitive decline, and the progression of viral load.
Antioxidants have anti-aging benefits
The signs of aging you can clearly see on your skin and experience in your body are the result of immune system and molecular changes, increased susceptibility to environmental stressors, Metabolic imbalances and diseases can occur as you age.3 These effects are the result of an imbalance between oxidative defense and ROS damage. Stem cell depletion, epigenetic changes, and changes in mitochondrial renewal also influence the aging process.
While signs of aging are common, you can take steps to minimize these effects. Maintaining optimal levels of nutrients and micronutrients is one of those steps. Evaluate4 in 2019 showed that the effects of selenium on aging occur in part through its role in selenoproteins, which are required for the expression of several important antioxidants.5
Selenium is used to express five distinct glutathione peroxidases,6 responsible for reducing damage from ROS. These and other selenoprotein compounds act as powerful antioxidants, reducing ROS-triggered inflammation and lengthening the length of telomeres, which are protective caps at the ends of DNA strands.7
When telomeres shorten to a critical length after division, cells die or stop dividing. These actions play an important role in the aging process, and some researchers suggest that selenium supplementation, especially in the elderly, could have “enormous implications” as a strategy to combat aging. prevent age-related diseases.8
Low selenium raises risk of heart and thyroid disease
Obesity is a significant risk factor for heart disease. A study published in March 20219,ten found that dietary selenium supplementation in animal models protected against obesity and increased the animal’s healthy lifespan. The researchers were also interested in whether selenium might have the same beneficial effects on metabolism as restricting the amino acid, methionine.
Selenium supplementation in this animal model provided the same protection against weight gain as methionine restriction and significantly reduced levels of the energy-regulating hormones IGF-1 and leptin. The results showed that selenium supplementation had almost the same effect as a methionine-restricted diet.11 But selenium can also have a direct impact on your cardiovascular system.
Scientists have been studying the effects of selenium on the cardiovascular system for decades, after discovering that the disease is more common in areas of the world with low serum selenium levels, such as such as in eastern Finland.twelfth
A meta-analysis13 in 2006, reviewed observational studies that assessed serum selenium levels and found them to be inversely associated with coronary heart disease risk. An important aspect of this study is that the researchers measured serum selenium levels and was not based on an assessment of supplementation alone.
In 2013, a systematic review of the Cochrane . database14 concluded that there is little evidence to support selenium supplementation for preventing heart disease. However, data from the studies showed that most participants had baseline or mean serum selenium levels between 70 and 150 nanograms per milliliter (ng/mL), which is the normal concentration found. in human serum.15
In other words, selenium supplementation is unlikely to be effective when serum levels are already within normal values. Another study16 published in 2020 also assessed serum selenium levels and found that those in the high range of the reference value had a reduced risk of cardiovascular disease and death.
Optimal selenium levels may also help people with heart failure. Research17 found that serum selenium levels were independently associated with exercise tolerance in heart failure patients, and that deficiency was associated with a 50% higher mortality rate.
Thyroid hormones also affect the cardiovascular system, and can cause or worsen heart disease, including heart failure and atherosclerotic vascular disease.18 Several studies have demonstrated that selenium supplementation in hyperthyroidism and hypothyroidism is associated with improvement.19,20,21
Age-related cognitive decline may be linked to low selenium
Preventing cognitive decline in the elderly is a significant public health challenge. A meta-analysis22 The collection of data from Europe, Australia and the Americas showed that the rates of mild cognitive decline per 1,000 person-years were 40.94 among 80- to 84-year-olds and 60.1 among 85-year-olds and older.
According to the Alzheimer’s Association, more than 6 million Americans are currently living with Alzheimer’s disease, and 1 in 3 older adults die with at least one form of dementia.23 One possible link is selenium as it is well understood that serum selenium concentrations generally decrease with age.
A longitudinal study24 found that a decrease in plasma selenium was associated with a decline in neuropsychiatric function in the elderly. Another study25 found that lower serum selenium levels were associated with decreased performance and neurological examination in older adults.
When serum deficiency occurs, the brain retains selenium the longest, suggesting that it plays an important role in brain function. Nine-year data review26 have suggested that maintaining an optimal selenium state is important for neuropsychiatric function in the elderly.
Low selenium and zinc linked to worse COVID outcomes
Selenium and zinc both play a role in supporting your immune system. One of the selenoprotein enzymes, glutathione peroxidase, is an important catalyst in the conversion of glutathione. This will reduce damage from reactive oxygen species.27 When glutathione peroxidase is compromised, the net effect is an overproduction of cytokines that can trigger a cytokine storm as seen in severe COVID-19 infections.
Selenium affects other pathways that also affect viral diseases. Author of an article in Environmental Studies28 note that HIV-1 cases are higher in areas of Africa where the soil is deficient in selenium and testing shows that Ebola infection is closely associated with people with severe selenium deficiency.
Coxsackievirus is an RNA virus that usually causes mild illness, but severe infections are found in areas of China where selenium is deficient.29 The authors suggested that these pathways influence a person’s response to a COVID-19 infection and hypothesized that supplementing with selenium during an active infection might help reduce damage endothelial cells.
Other studies in China30 and Germanythirty first demonstrated that there is a positive relationship between the survival rates of people with active COVID-19 infections and selenium levels.
Research32 published in 2021 to identify predictive markers that doctors can use to better stratify COVID-19 patients on admission. In this study, the researchers measured serum zinc, iron, copper, and selenium levels. The level of Selenoprotein P was also measured, which requires selenium for full expression.
The researchers found that cancer patients had significant deficiencies in selenium and zinc. Three of the five patients with the lowest iron levels, who also had severe zinc and selenium deficiencies, died during the study. Analysis of biomarkers revealed that most of the hospitalized patients had exceptionally low levels of selenium and zinc.
When patients with comorbidities were analyzed, they found marked deficiencies in iron, zinc, and selenium and a higher chance of survival in cancer patients with higher selenium levels. The researchers concluded that the data confirm:33
“…insufficient Se (total Se and SELENOP) and Zn status on admission is associated with a particularly high risk of mortality and severe disease progression with COVID-19.
With a view to accurately predicting Se and Zn deficiency as risk factors for mortality on admission, supplemental delivery of Se and Zn should be considered to support the immune system, especially for those with patients with inflammatory comorbidities such as cancer or diabetes. ”
Deficiency Signs and Selenium-Rich Food Choices
Selenium is found in soil and should be concentrated in plant foods. However, experts estimate that as many as 1 billion people globally may be deficient due to inadequate intake of nutrients.34
An article published in Environmental Research35 cites a report by the World Health Organization that shows more than 40 countries where the soil is deficient in selenium. Some of the lowest levels are found in New Zealand, Slovakia, Finland and sub-Saharan Africa.
People with a selenium deficiency are at increased risk for diseases that affect the endocrine system, cardiovascular system, immune system, and reproductive system, and that can affect mood and behavior.
While testing is needed to determine if you’re deficient, some symptoms may indicate that you’re not getting enough selenium in your diet. They may include:36,37,38
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Hair loss |
Tired |
Weight gain |
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Sick more often |
Oxidation stress is greater |
Short of breath |
|
Cognitive decline |
Muscle weakness |
I recommend getting as many essential vitamins, minerals and elements from your diet as possible. The recommended daily intake of zinc ranges from 2 mg for infants to 11 mg to 8 mg for men and women over 19 years of age.39 Food sources include oysters, pasture-raised beef, dark chicken, pumpkin seeds and dry roasted cashews.
The recommended daily allowance for selenium is from 15 micrograms (mcg) for infants to 55 mcg for men and women over 19 years of age.40 The best food sources of selenium are Brazil nuts. Just six to eight nuts provide 544 mcg, or 989% of your daily intake. Other sources include sardines, pasture-raised beef, turkey, chicken, and pasture-raised eggs.
