Selenium May Reduce the Risk of Heart Disease and Some Cancers

Reduced risk of heart disease and reduced risk of some cancers. Increasing the daily intake of selenium among individuals with low selenium status may reduce the risk of cardiovascular disease and some cancers. The available data seem to show that most adults in the Nordic and Baltic countries, with the exception of adults in Finland, have low selenium intakes and low selenium status [Alexander & Olsen 2023].

Jan Alexander
Prof. Jan Alexander, MD, PhD, Norwegian Institute of Public Health in Oslo, says: There are various factors that influence cardiovascular disease mortality and cancer incidence: diet, lifestyle, genetics, inter alia. The impact of these factors varies from one Nordic country to the next.

Selenium is an essential trace element. The human body cannot synthesize it. It must come from the diet and supplements. Selenium is a vital component of selenoproteins that are critical to normal health and physiological functioning. This is the fundamental message from a 2023 selenium scoping review conducted for the Nordic Nutritional Recommendations 2023 [Alexander & Olsen 2023]. read more

Selenium Delays Cognitive Decline

In the Swedish KiSel-10 clinical trial, the study participants had an average age of 78 years at the start of the study [Alehagen 2013]. Their serum selenium concentration at baseline was at a deficiency level (mean: 67.1 mcg/L).

Woman meditating
Diet, exercise, and meditation are all important to good brain health. Dietary and supplemental selenium crosses the blood-brain barrier. Supply of selenium to the brain has a higher priority than supply to other organs. Low selenium status is associated with cognitive decline.

Moreover, the low selenium status of the elderly Swedish citizens was significantly associated with relatively high mortality risk [Alehagen 2016]. Daily supplementation with 200 mcg of a selenium-enriched yeast preparation together with 200 mg of Coenzyme Q10 raised the study participants’ serum selenium levels to 210 mcg/L and reduced the risk of cardiovascular mortality [Alehagen 2022a].

The four years of joint supplementation were associated with the following positive health outcomes: read more

Selenium Intakes and Health Outcomes

Selenium and good health. How much do we need? How do we get it? Generally speaking, our family and friends do not know just how important selenium is to good health. Our bodies cannot synthesize selenium. We are dependent upon food for an adequate daily intake of this essential trace element.

Salmon rich in selenium
Depending upon where we live, the selenium content of our food may be too low. Wang et al [2023] estimate that approximately one billion people worldwide lack sufficient selenium in their diet.
In many regions of the world, the soil and the foodstuffs have a poor selenium content. Accordingly, the daily intake of selenium varies considerably. Many people have an inadequate supply and thus risk poor health outcomes as a result. For example, in much of Europe, the UK, and the Middle East, there are widespread reports of suboptimal selenium status. Supplementation is necessary in selenium-poor regions [Stoffaneller & Morse 2015]. read more

Selenium Status and HIV Infections

HIV (human immunodeficiency virus) is still very much a public health concern. Deficiencies of certain micronutrients are known to play a role in the progression of HIV infections to AIDS (acquired immunodeficiency syndrome). In particular, adequate intakes of selenium are important because of selenium’s antioxidant and anti-inflammatory activities in HIV infection [Pourmoradian 2023].

Umbrella Study of Systematic Reviews of Selenium and HIV Studies

Symptoms of AIDS Poster
Selenium levels are often low in individuals infected with HIV virus. Selenium supplementation can slow the decline in CD4 cell counts, can reduce the risk of hospitalization, can prevent increases in the HIV-1 viral load, and can slow the progression of the infection to AIDS.

In a 2023 umbrella study of systematic reviews of studies of selenium in HIV patients, Pourmoradian et al found the following evidence:

  • Four reviews showed that selenium supplementation at the level of 200 mcg/day was effective in delaying CD4 decline in HIV-infected patients.
  • Three reviews showed that selenium supplementation at the level of 200 mcg/day significantly reduced HIV viral load.
  • The researchers suggested that the underlying mechanism of the selenium effect on HIV progression is the improvement of the immune response and the antioxidant defense system.
  • In particular, the selenium-dependent glutathione peroxidase (GSH-Px) enzyme system reduces the extent of oxidative stress, indirectly strengthens the immune system, and slows the progression of the disease.

Note: CD4 cells are lymphocytes that help to coordinate the immune response to infections. If an HIV patient’s CD4 cell count falls below 200 cells per cubic millimeter of blood, then the HIV infection is considered to have progressed to the AIDS stage. In healthy individuals, the CD4 count will be between 500 and 1,600 cells/cubic millimeter of blood. read more

Selenoprotein P – Selenium Transport Protein and Biomarker of Selenium Status

Selenium and selenoproteins are essential to human health [Rayman 2012]. However, selenium intakes from food vary considerably from region to region in the world, depending on how rich or poor the soil and the foodstuffs are.

Selenium researcher Professor Urban Alehagen
Professor Urban Alehagen realized that the low selenium content of the soil in Sweden and in much of Europe results in wide-spread low dietary selenium intake and selenium deficiency. In the Swedish KiSel-10 Study, the average serum selenium concentration was a quite low 67 mcg/L.

For example, widespread suboptimal selenium status has been reported throughout Europe, the UK, and the Middle East [Stoffaneller & Morse 2015]. In contrast, the soil and the foodstuffs in much of the United States and Canada have a much higher selenium content than is the case in Europe. Serum selenium levels of US citizens are generally above 120 mcg/L. In many European countries, the corresponding serum selenium levels are 90 mcg/L on average [Alehagen 2016].

  • The best estimate for serum selenium status that is sufficient for good health is around 125 mcg/L [Winther 2020, fig. 3].
  • Serum selenium levels below 70 mcg/L are indicative of selenium deficiency [Bomer 2020].
  • Serum selenium levels below 100 mcg/L are indicative of sub-optimal selenium status [Al-Mubarak 2021].
Selenoprotein P as the Major Selenium Transport Protein

Dietary selenium is incorporated into the amino acid selenocysteine, which becomes an integral component of 25 selenoproteins. The best known selenoproteins are the glutathione peroxidases, thioredoxin reductases, and
iodothyronine deiodinases [Schomburg 2019]. read more

Selenium Supplementation Increases Serum Sirtuin1 Concentrations

Daily supplementation with 200 mcg of selenium and 200 mg of Coenzyme Q10 for four years has resulted in significant increases in serum SIRT1 concentrations. In the parallel placebo group, the serum SIRT1 concentrations decreased significantly [Opstad, Alehagen 2023].

Selenium Researcher Professor Jan Aaseth
Professor Jan Olav Aaseth, Inland Norway University of Applied Sciences, is the guest author on this review article. Dr. Aaseth has written extensively about selenium in health and disease. He is one of the co-authors on the Sirtuin1 study summarized here.

This is the latest evidence from the KiSel-10 Study in which researchers randomly assigned elderly community-living Swedish men and women, average age: 76 years, 49% female, to a combined selenium and Coenzyme Q10 treatment group or to a placebo group [Alehagen 2013].

In earlier papers, the KiSel-10 Study researchers have reported beneficial effects of the combined supplementation of the elderly Swedish citizens with low baseline selenium levels [Alehagen 2022; Opstad 2022]: read more

Selenium Supplementation and Chemotherapy in Cervical Cancer Patients

Selenium yeast supplementation administered concurrently with chemotherapy and radiation therapy effectively increased blood selenium levels in cervical cancer patients with inadequate selenium status. The selenium yeast supplementation was used as an adjuvant treatment to the standard chemotherapy and radiation therapy. It significantly decreased the hematologic toxicity of the chemoradiotherapy [Yang 2023].

Cancer and selenium
Each year, worldwide, half a million women are diagnosed with cervical cancer, and 300 000 die from the disease. In most cases, the human papilloma virus is the cause of the disease [Cohen 2019]. The trace element selenium has antiviral properties. Cell studies and mouse studies of cervical cancer have shown that different selenium species have anticancer effects in cervical cancer induced by human papilloma virus or by chemical carcinogens [Jablonska 2021].
In a randomized controlled trial, researchers randomly assigned 104 patients diagnosed with stage IIB cervical cancer receive 100 mcg selenium yeast tablets (n=50) or matching placebos twice daily (n=54) for five weeks [Yang 2023].

All patients in both groups received the standard treatment including pelvic external irradiation, concurrent five cycles of chemotherapy, and brachytherapy [Yang 2023]. read more

Selenium and a Longer Healthier Life

The micronutrient selenium has antioxidant and anti-aging properties. Specifically, numerous selenoproteins, in which selenium is an essential component, have antioxidant, anti-inflammatory, and immunostimulating effects [Bjørklund 2022].

Why is this important?

Old people
Biological aging involves the gradual worsening of the composition of our cells and organelles. It involves the slowing down of our body functions. Aging is typically accompanied by wrinkled skin and thinner skin, by a loss of body mass and bone density, and by poorer eyesight. The older we get, the more vulnerable we are to loss of cognitive function and dementia, heart trouble, osteoporosis, renal failure, viral infections, etc. Eventually death comes.

The aging process is characterized by the following inevitable physiological developments [Alehagen 2021]:

Selenium and selenoproteins and antioxidant protection

One theory of biological aging is that oxidative stress and chronic low-grade inflammation play an important role in aging-related physical and mental decline. Harmful reactive oxygen species – popularly known as free radicals – overwhelm the ability of the available antioxidants to neutralize them. The harmful free radicals cause oxidative damage to the cells and to the DNA, lipids, and proteins in the cells [Bjørklund 2022]. read more

Thyroid Disorders and Selenium Supplementation

Thyroid disorders.

Many clinicians treating autoimmune thyroid diseases are using selenium supplementation as one treatment modality even though, in the official guidelines, selenium supplementation is recommended only in the treatment of mild Graves orbitopathy [Winther 2020].

Thyroid gland
The thyroid gland is the butterfly-shaped organ in the front part of the neck. Thyroid hormones regulate body temperature, heart rate, and weight gain or loss. Autoimmune thyroid disorders occur when immune system cells attack thyroid gland cells. Autoimmune thyroid disorders cause overproduction of thyroid hormones (hyperthyroidism) and underproduction of thyroid hormones (hypothyroidism). Graves’ disease is the most common autoimmune hyperthyroidism. Hashimoto’s thyroiditis is the most common autoimmune hypothyroidism.

Some clinicians consider supplementation with selenium to be a pharmaceutical action that should be taken only with thyroid disorder patients with well-defined symptoms in order to alleviate the symptoms, to improve the course of the disease, or to provide a cure. Typically, in such cases, the selenium treatment is conducted for short periods, and the health benefits and side effects are evaluated and weighed [Schomburg 2020].

Other clinicians consider supplementation with selenium in a more holistic way and use selenium supplementation as a way to correct a nutritional deficiency of selenium, which is associated with thyroid disorders [Schomburg 2020]. read more

Selenium Supplementation and Alzheimer’s Disease

Clinical studies show a clear correlation between Alzheimer’s Disease and low selenium status.  Lower selenium status is associated with worse cognitive decline [Aaseth 2016].

In many regions of Europe and the Middle East, there is poor selenium content in the soil and, accordingly, lower intake of selenium from food sources [Stoffaneller & Morse 2015; Winther 2020].

Woman with Alzheimer's
Adequate levels of selenium are essential for brain function; in fact, the brain is one of the organs that is supplied with selenium at the expense of other organs and tissues in times of low selenium intake. Selenoprotein P plays a special role in delivering selenium to the brain and the neurons. Some of the glutathione peroxidase and thioredoxin reductase selenoenzymes are important intracellular antioxidants in neurons and glia cells of the central nervous system.

The daily intake of selenium from food in many European countries is well below the amount needed for optimal function of important selenoproteins. The needed intake of selenium from food is  estimated to be at least 105 mcg per day [Winther 2020, fig. 2].

Using evidence from human studies in various countries, Prof. Jan Aaseth and colleagues have documented the association between lower selenium  status and Alzheimer’s Disease and/or cognitive impairment [Aaseth 2016]. read more