Selenium Supplementation and Anti-Ageing Effects

The development of ageing-related diseases seems to be closely related to the extent of damage inflicted on the cells by oxidative stress. Researchers define oxidative stress as damage to proteins, nucleic acids, and lipids caused by an imbalance between harmful reactive oxygen species (frequently referred to as free radicals) and the body’s antioxidative defenses [Alehagen 2021].

Elderly couple on the beach
We want to stay as young as possible as late in life as possible. Ensuring that we have an optimal intake of selenium is associated with protection against several aspects of ageing.

A 2021 review of the relevant research literature reveals the following findings [Alehagen 2021]:

-Optimal selenium status is necessary for the synthesis of the antioxidant seleno-enzymes: the glutathione peroxidases and the thioredoxin reductases.

-Selenium deficiency in elderly individuals seems to increase the risk of developing age-related diseases: chronic inflammation, cardiovascular disease,  cancer, and neurodegenerative diseases. read more

Selenium and Kidney Function

Here are the main points from a recent review article on the topic of aging and exposure to heavy metals and kidney function:

Kidney cross section
Professor Jan Aaseth and his colleagues have reviewed the research literature about the response of the aging kidney to environmental toxicants like mercury, cadmium, and lead. Selenium may have a protective effect in that it binds to and sequesters the harmful heavy metals and also serves to reduce the level of oxidative stress.

The efficiency with which the kidneys remove waste and excess fluid from the blood declines with age in individuals who are older than 50–60 years.

  • Exposure to metal pollutants may be detrimental to the kidneys of normal healthy adults and exacerbates the functional decline of the kidneys in seniors. Given the prevalence of these heavy metal toxicants in the environment, it is nearly impossible for people to avoid exposure.
    • Studies have shown that exposure to mercury, cadmium, and/or lead is associated with an increase in the incidence and the severity of kidney disease in elderly individuals. There is some reason to think that adequate selenium status helps to protect against the damage of heavy metal toxicants.
    • Unfortunately, the early signs of kidney dysfunction often go unnoticed.
    Mercury, Cadmium, Lead – Difficult to Avoid

    Prof. Aaseth et al. write that toxic metals are so abundant in the environment that it is almost impossible for humans to avoid contact with them. read more

    Low Selenium Status and Autoimmune Diseases

    Selenium is an essential trace element, essential in the sense that our bodies cannot synthesize it, and we must get what we need of it in our diets.

    Elderly people
    Professor Schomburg distinguishes between selenium substitution – supplying selenium to correct a nutritional deficit – and selenium supplementation – supplying selenium on top of a sufficient baseline status for therapeutical purposes. Here, elderly people with joint pain.

    Suboptimal intakes of selenium, i.e., intakes below the recommended intake levels, are associated with increased disease risks, in particular increased risk of autoimmune diseases, chronic diseases, inflammation, etc.

    Unfortunately, the health risks of selenium deficiency are often neglected. Here are some facts:

    • Preventable endemic diseases are known in regions with selenium deficiency, e.g., in certain parts of China.
    • Sufficiently high selenium status is a prerequisite for adequate immune system response.
    • Individuals living in regions with selenium-poor soil, women who are  pregnant, individuals with autoimmune thyroid disease, and individuals with a severe illness, e.g. COVID-19, are known to have sub-optimal selenium intakes and status.
    • Improved dietary choices and/or selenium supplementation are efficient ways to avoid severe selenium deficiency.

    These are the major points in a recent journal article published by Professor Lutz Schomburg, Charité–Universitätsmedizin Berlin, Freie Universität Berlin, and Humboldt Universität zu Berlin.

    Selenium and Selenoproteins

    The micronutrient selenium is a component of the amino acid selenocysteine, which is itself an essential part of some 25 selenoproteins identified in human biology. Some selenoproteins are known to be essential for life; accordingly, they are preferentially synthesized and distributed. The brain, for example, has high priority for selenium in times of scarcity. read more

    Covid-19 and Selenium and Coenzyme Q10

    The individual’s status of selenium and Coenzyme Q10 may be a decisive factor in his or her immune system’s response to the SARS-CoV-2 virus that causes the acute respiratory distress of a Covid-19 infection.

    Corona virus
    A research review shows that selenium and CoQ10 supplementation has positive effects on the free radical-induced oxidative stress and the inflammation associated with patients with COVID-19 disease.

    In particular, immune system cells require adequate selenium and Coenzyme Q10 to protect against oxidative stress and to modulate the inflammatory effect.

    This is the conclusion of the authors of a 2021 review of the relevant research literature [Hargreaves & Mantle].

    Iain R. Hargreaves, a biochemistry faculty member in the Pharmacy and Biomolecular Sciences Department of the Liverpool John Moores University, together with the medical doctor David Mantle, has written that adequate selenium status and adequate Coenzyme Q10 status may be important factors: read more

    What is an Adequate Selenium Status?

    Many people in the world live in regions with selenium-poor soil and, consequently, with selenium-poor food. The body cannot synthesize selenium, which is an essential non-metal trace element that we need in small amounts. A recent review of selenium status and the risk of cardiovascular disease suggests that serum selenium status below 100 mcg/L is associated with increased risk of heart disease, with reduced exercise capacity, with reduced quality of life, and with worse prognosis [Al-Murbarak].

    • Low intakes of selenium mean low selenium status.
    • Sufficient selenium is required for the formation of the amino acid selenocysteine, which is, in turn, an essential component of selenoproteins.
    • Low selenium status over longer periods of time can put individuals at greater risk of cardiovascular disease, cancer, and autoimmune thyroid disorders.
    • Adequate selenium intake and status are necessary for good immune function and protection against infectious diseases.Doctors' conference
    • Particularly vulnerable to have low selenium status are individuals who are vegetarians and vegans, pregnant and breastfeeding women, overweight or obese individuals, HIV-patients, kidney-dialysis patients, and individuals on parenteral nutrition as well as individuals living in selenium-poor regions.

    Where is selenium status likely to be low?

    Stoffaneller and Morse conducted a comprehensive study – 143 references – of selenium status in Europe, the UK, and the Middle East. They concluded that selenium intake and status are generally suboptimal in European and Middle Eastern countries, with somewhat more variation in the Middle East. They reported that suboptimal selenium status is widespread throughout Europe and the UK, with Eastern European countries having lower selenium intakes than Western European countries. In the Middle Eastern countries, they found varying results, which were possibly caused by different food habits and different imports in different regions and within differing socioeconomic groups [Stoffaneller & Morse]. read more

    Pharmacokinetics of Oral Selenium-Enriched Yeast Supplements

    The Danish researchers Niels Hadrup and Gitte Ravn-Haren have published a comprehensive study of the absorption, distribution, metabolism, and excretion of selenium obtained from food and from nutritional supplements [Hadrup 2021].

    Pills
    Selenium supplements come in many forms, both organic and inorganic. The advantage of the selenium-enriched yeast preparations is that they contain 20-30 different species of selenium in addition to selenomethionine. Some of these selenium species may have important biological effects.

    Here we summarize their findings with respect to selenium in selenium-enriched yeast supplements. We do this for two reasons:

    Absorption of selenium from selenium-enriched yeast preparations

    In a 2008 paper, researchers reported having given healthy elderly individuals 100, 200 or 300 mcg selenium in a selenium-enriched preparation daily for a period of 5 years. The supplementation resulted in mean plasma levels of 165, 221, and 260 mcg/L, respectively. In the control group, given a placebo for 5 years, the plasma selenium concentration was 92 mcg/L [Ravn-Haren 2008]. read more

    Selenium and Patients with Autoimmune Thyroid Disease

    Sufficient selenium status is necessary for good thyroid health.

    A woman's neck
    Selenium-containing drugs are effective for treating patients with autoimmune thyroid disorders [Zuo 2021].
    Zuo et al [2021] have investigated selenium status and the effects of selenium supplementation in patients with autoimmune thyroid disease.

    They analyzed the data from 17 journal articles based on studies of 1,911 subjects. Their meta-analysis results showed the following statistically significant associations:

    • Serum free triiodothyronine (FT3) levels in patients were reduced after selenium supplementation compared to placebo treatment.
    • Serum free thyroxine (FT4) levels and anti-thyroid peroxidase antibody (TPOAb) levels were reduced after selenium supplementation compared to placebo treatment.
    • Anti-thyroid peroxidase antibody (TPOAb) levels were decreased after selenium supplementation compared to placebo treatment.

    However, the thyroid stimulating hormone (TSH) levels
    and the anti-thyroglobulin antibody (TGAb) levels were not significantly different between the selenium treatment group and the control group.

    The researchers concluded that selenium-containing drugs were effective in treating patients with autoimmune thyroid disease and greatly reduced
    the levels of free triiodothyronine, free thyroxine, and anti-thyroid peroxidase antibody in these patients. read more

    Selenium Status and Risk of Non-Alcoholic Fatty Liver Disease

    Data from an observational study done in the United States have shown the following relationships [Reja 2020]:

    Upper right abdomen pain
    Liver pain is usually felt as a dull, throbbing pain in the upper right abdomen. NAFLD is the most common form of liver disease. It is characterized by the storing of too much fat in liver tissues, by inflammation, and by fibrosis. Liver fibrosis is a degenerative disease in which liver tissue is damaged and replaced by scar tissue.

    Higher serum selenium status is correlated with lower risk of advanced liver fibrosis.

  • This correlation is especially strong in liver disease patients who are elderly, who are non-Hispanic white, or who are female.
  • The patients with non-alcoholic fatty liver disease (NAFLD) who had higher serum selenium levels also had a 28% lower hazard ratio of death from all causes compared to the NAFLD patients with the lowest serum selenium levels.
  • Serum Selenium Levels and the Risk of Advanced Liver Fibrosis and All-Cause Mortality in NAFLD Patients
    What was the study based on?

    The data analyzed in the study came from 33,944 NAFLD patients identified in the Third National Health and Nutrition Examination Survey (NHANES). read more

    Serum Selenium Status and Cancer Risk

    On its Selenium: Fact Sheet for Health Professionals website, the US Office of Dietary Supplements, an agency of the National Institutes of Health, writes that selenium might play a role in the prevention of cancer for the following reasons:

    • selenium’s role in DNA repair
    • selenium’s role in apoptosis
    • selenium’s role in the endocrine and immune systems
    • the antioxidant properties of certain selenoproteins
    Cancer prevention ribbons
    It is not possible to draw any conclusions regarding a causal link between selenium exposure/status and the prevention of cancer. However, numerous observational studies show an inverse relationship between serum selenium status and the risk of cancer.
    Different Selenium Compounds Have Different Effects on Cancer

    The evidence from scientific research into the effect of selenium on cancer prevention can be confusing. Two observations about selenium supplementation may help to explain the confusing results from existing selenium and cancer studies:

    1. Different selenium containing compounds differ widely in their ability to prevent cancer. Study results may vary according to the form of the selenium supplement tested.

    2. Selenium supplementation may be more effective at cancer prevention in study participants with low baseline selenium status (below 100 mcg/L) and less effective in study participants with high baseline selenium status (above 135 mcg/L). read more

    Selenium Supplementation and Male Infertility

    Clinical studies show that daily supplementation with selenium can improve male fertility [Moslemi et al.; Safarinejad & Safarinejad; Scott et al.].

    Stork bringing baby
    Sperm motility is a parameter of sperm analysis used to evaluate the ability of sperm to move in a forward direction. Poor sperm motility is associated with diminished male fertility. Adequate serum selenium status (> 90-100 mcg/L) is associated with improved sperm quality and improved sperm motility.
    Selenium Supplementation of Men in Iran in 2009

     In a 2009 study lasting 26 weeks, researchers in Teheran randomly assigned infertile men, average age 31 years, range 25-48 years, to the following groups [Safarinejad & Safarinejad]:

    1. selenium supplementation group (n=116; dosage = 200 mcg/day)
    2. N-acetyl-cysteine group (n=118; dosage = 600 mg/day)
    3. selenium supplementation group (n=116; dosage = 200 mcg/day) plus N-acetyl-cysteine (dosage = 600 mg/day)
    4. placebo group (n=118)
    Outcomes of the 2009 Iranian selenium study:
    •  All semen parameters significantly improved with the selenium treatment and with the N-acetyl-cysteine treatment.
    • Administering selenium plus N-acetyl-cysteine resulted in additive beneficial effects.
    • There was a significant positive correlation between the seminal plasma concentrations of selenium and N-acetyl-cysteine and the semen parameters.
    • There was a strong correlation between the sum of the selenium and N-acetyl-cysteine concentrations and the mean sperm concentration, sperm motility, and percentage of normal morphology sperm.
    Selenium Supplementation of Men in Iran 2011

    In an open-label study of 690 infertile men, average age 28.5 years, range 20-45 years, who received a daily selenium supplement (200 mcg) together with a daily synthetic vitamin E (400 units, α-tocopherol) for at least 100 days, the researchers concluded that supplemental selenium and vitamin E improve semen quality and have beneficial effects on sperm motility [Moslemi et al.]. read more