Selenium Deficiency and Immune Function

Less systemic inflammation. Better immune function. Selenium is an essential trace element. Our cells cannot synthesize it. We must get it as a part of our diets. Adequate intakes are necessary for optimal immune system function.

Man in wheelchair at the beach
Autoimmune diseases develop when our own immune system malfunctions and attacks our cells. Then we suffer from autoimmune thyroid disorders, lupus, multiple sclerosis, psoriasis, rheumatoid arthritis or a hundred other autoimmune diseases.

Unfortunately, many of us live in regions with selenium-poor soil and selenium-poor crops and fruits. We do not get sufficient selenium from our food [Stoffaneller & Morse 2015]. Adequate selenium intake and status are vital. There are increased health risks associated with selenium deficiency.

What Defines Selenium Deficiency?

Data from the BIOSTAT-CHF observational cohort study indicate that serum selenium concentrations under 70 mcg/L constitute a deficiency status. Serum selenium concentrations under 100 mcg/L constitute a sub-optimal status [Bomer 2020]. read more

Selenium and Hypothyroidism

In the CATALYST study, researchers found that selenium supplements and placebo supplements improved the quality of life of patients with hypothyroidism to an equal extent. Accordingly, the researchers have now emphasized a need for more research into the effect of selenium supplementation on immune system function, on oxidative stress, and on low-grade inflammation in patients with thyroid diseases [Larsen 2024].

Thyroid system depicted
Depiction of the thyroid system. Attribution: Attribution: Mikael Häggström, Public domain, via Wikimedia Commons. The CATALYST study (Chronic Autoimmune Thyroiditis Quality of Life Selenium Trial) sought to establish whether selenium supplementation improves quality-of-life in patients with autoimmune thyroiditis .

The CATALYST study was a multi-center randomized, double-blinded, placebo-controlled clinical trial conducted in Denmark. The study participants were patients aged 18 or more years with serum thyroid peroxidase antibody (TPOAb) levels equal to or greater than 100 IU/mL. 82% of the study participants were women [Larsen 2024]. read more

Selenium and Human Longevity

The absorption of dietary and supplemental selenium has an important and positive influence on human longevity. Selenium researchers have called selenium a “longevity element.” The selenoenzymes and selenoproteins of which selenium is an essential component have antioxidant, anti-inflammatory, and anti-cancer activity in humans [Li 2024].

Great Wall of China
Typically, China has many regions with selenium-poor soil and selenium-poor foodstuffs. Some regions, however, do have selenium-rich soil and selenium-rich crops and fruits. One such region is characterized by the longevity of its residents. Selenium seems to be a factor in anti-aging.

Maintaining selenium absorption and metabolism at an optimal physiological state seems to be one of the primary factors for good health and longevity of the elderly people. In particular, scientific studies have shown that selenium intake and status play an important role in the incidence and progression of some chronic diseases [Li 2024]:

  • Cancer: inducing tumor cell apoptosis, reducing the mutagenicity of carcinogenic factors, prolonging the cell division interval, and slowing proliferation of malignant cells
  • Heart failure: improving exercise tolerance, reducing mortality rate, and improving quality of life
  • Heavy metals: binding to mercury, sequestering mercury, reducing mercury’s biological availability and reducing the damage to the kidney caused by exposure to heavy metals
  • Antioxidant effects: restoring the antioxidant defense system of the body
Selenium-Rich Soil in a Chinese Longevity Township

Bama Yao Autonomous County is the only longevity township in China that is globally recognized as having a continuously growing longevity population. In 2020, Bama had 102 residents over 100 years old. The number had increased from the 2000 census (74 residents over 100 years of age) and the 2010 census (82 residents over 100 years of age). Bama has relatively stable genetic and geographic factors and a relatively stable dietary culture [Li 2024]. The proportion of centenarians is nearly six times greater than the international standard proportion [Zhang 2023]. read more

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 and Selenoprotein P and Mortality

Higher all-cause mortality and higher mortality due to cancer, cardiovascular disease, gastrointestinal diseases, and respiratory disorders are associated with lower serum selenoprotein P concentrations in older German adults [Schöttker 2024].

Operation table
Death from all causes and death specifically caused by cancer, cardiovascular disease, gastrointestinal diseases, and respiratory disorders are strongly associated with low serum concentrations of the selenium-dependent selenoprotein P.

In plain English, lower blood concentrations of the selenium-dependent selenoprotein P are significantly associated with a higher risk of degenerative disease progression and with dying. Moreover, the data from the German study show that the risk of dying associated with low blood Selenoprotein P levels was more than double in men compared to women [Schöttker 2024].

In the Esther Study, German researchers assessed the association of measurements of serum Selenoprotein P concentrations with all-cause and cause-specific mortality data. They measured serum Selenoprotein P at baseline and again at a 5-year follow-up in 7,186 and 4,164 participants, respectively [Schöttker 2024]. 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 Mortality Risk

Mortality and morbidity. As we get older, we start to think about ways to reduce the risk of an early death. We want to reduce the risk of living out our lives in ill health.

Zion National Park in the USA
Pictured here: A creek in the Zion National Park in Utah.

We think about diet, exercise, 10,000 steps a day, hobbies, social contact. But, do we think about our selenium intake and status? Now, some large survey studies conducted in the US have shown that higher selenium status is significantly associated with lower mortality.

Each year, the National Health and Nutrition Examination Survey (NHANES) in the United States conducts surveys that focus on different population groups or health topics. This week, we present data from studies of selenium status and mortality.

Selenium Status and Type 2 Diabetes

Qiu et al examined the data from 3199 adults with type 2 diabetes. Their analysis showed that higher serum selenium concentrations are associated with lower all-cause mortality and lower heart disease mortality among individuals with type 2 diabetes [Qiu 2022]. read more

ChatGPT Answers About Different Forms of Selenium Supplements

In our last article, we asked ChatGPT about the health benefits of selenium supplements in Europe. This time, we asked what is the best form of selenium supplement?

ChatGPT about selenium
We asked ChatGPT for information about the various forms of selenium supplements.

ChatGPT answered that the best form of selenium supplement depends on various factors. These factors include individual health needs, dietary habits, and preferences. Each different form of selenium supplement has its own set of advantages and considerations.

  • Selenomethionine: This form of selenium is found in foods like Brazil nuts, grains, and legumes. The body absorbs selenomethionine well.
  • Sodium selenite: This is an inorganic form of selenium. It is generally considered to have lower bioavailability compared to organic forms like selenomethionine and selenium yeast.
  • Selenium yeast: Selenium yeast is produced by fermenting the yeast Saccharomyces cerevisiae in the presence of selenium. It contains various species of selenium including selenomethionine. The yeast is inactivated in the supplements.

Editor’s note: The presence of various other species of selenium in the selenium yeast may be important for cancer prevention. By other species, we mean the selenium species other than the selenomethionine that is in the selenium yeast supplements.

  • In the Nutritional Prevention of Cancer study, researchers administered 200 mcg/day of selenium-enriched yeast for an average of 5.4 years. The study results showed a significant reduction of colorectal, lung, prostate, and total cancer incidence [Clark 1996].
  • In the SELECT study, researchers administered selenium in the form of selenomethionine, 200 mcg/day. The supplementation with selenomethionine alone and also together with vitamin E did not show any reduction of the risk of colorectal, lung, or prostate cancer after 5.5 years of follow-up [Lippman 2009].

Thus, it seems that the protective effect against cancer may have come from one or more of the other selenium species in the selenium yeast preparation, not from the selenomethionine in the preparation [Bjørnstedt 2010]. read more

ChatGPT Answers Selenium Health Benefits Question

How does ChatGPT answer the question: what are the health benefits of selenium supplementation in Europe? Earlier this month, we posed that question to the free version of ChatGPT. We focused on Europe because the selenium intakes in the United States are generally much higher than the selenium intakes in many parts of Europe [Alehagen 2022].

ChatGPT and selenium supplementation
ChatGPT links selenium supplementation to antioxidant protection, cancer prevention, heart health, immune function, and thyroid function. Important to talk with a health professional about selenium intakes and the need for selenium supplementation.

First, ChatGPT explained that selenium is an essential trace element. It plays an important role in physiological processes in the body. It is a necessary component in selenoproteins. These selenoproteins have antioxidant properties. They help regulate immune system function, thyroid function, and DNA synthesis.

Next, ChatGPT reminded that excessive intake of selenium can lead to toxicity. Selenium supplementation should be undertaken under the guidance of a healthcare professional. Note that the Nordic Nutrition Recommendations 2023 and the European Food Safety Authority both set the tolerable upper intake level at 255 mcg/day [Blomhoff 2023; EFSA 2023]. read more