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Selenium and Antioxidants to Prevent Heart Disease

Heart trouble
Selenium deficiency (< 70 mcg/L) and low selenium status (70 – 100 mcg/L) are associated with reduced exercise capacity and higher risk of death in heart failure patients [Bomer 2019].
Canadian researchers have concluded that the addition of selenium should be considered for antioxidant supplements if the antioxidant mixtures are to be associated with reductions in the risk of heart disease and all-cause mortality [Jenkins 2020].

How did they arrive at this conclusion? First, they did a preliminary analysis of the available research literature and found that antioxidant supplements seemed to reduce incidence of all-cause death when the supplements included selenium [Jenkins 2020].

Systematic Review of Supplements With and Without Selenium

Next, they did a systematic review and meta-analysis of randomized controlled trials to evaluate the effect of selenium supplementation alone and the effect of antioxidant mixtures with or without selenium on the risk of heart disease and all-cause mortality [Jenkins 2020]. read more

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Selenium Supplementation and Rheumatoid Arthritis

Arthritic hands
Rheumatoid arthritis patients typically have lower serum selenium status than healthy individuals do. Some studies show that selenium supplementation is associated with reduced swelling and stiffness of the joints and with less severe pain in rheumatoid arthritis patients.

A meta-analysis shows a significant association between low serum selenium status and rheumatoid arthritis (RA) [Yu 2016].

-The researchers examined the data from 14 case-control studies involving 716 subjects.

-The analysis of the pooled data indicated that patients with rheumatoid arthritis had lower serum levels of selenium than the healthy controls.

-The rheumatoid arthritis patients had significantly lower serum selenium levels than healthy controls did in studies in Europe and in Asia but not in studies in the USA.

Selenium and Rheumatoid Arthritis Studies

Sahebari et al [2019] reported on 13 studies that assessed selenium status in rheumatoid arthritis patients.

Adequate Selenium for Rheumatoid Arthritis Patients

Rheumatoid arthritis is a chronic inflammatory disease that affects the joints of the hands and feet and leads to disability. read more

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Low Selenium Status and At-Risk Pregnancies

Pregnant woman
Low serum selenium status (defined as below 80 micrograms per liter) during pregnancy is associated with increased risk of miscarriage, pre-eclampsia, pre-term births, and other adverse outcomes.

A recent review article presents the evidence that low selenium status in pregnant women may be implicated in the following complications [Duntas 2020]:

  • miscarriage
  • preeclampsia
  • pre-term birth
  • retarded fetus intrauterine growth
  • post-partum hypothyroidism and auto-immune thyroiditis

To ensure an optimal pregnancy outcome, Dr. Leonidas Duntas recommends that physicians take an individualized approach and prescribe dietary and supplemental selenium intakes that are tailored to the pregnant woman’s needs.

Why is Adequate Selenium Important for Pregnant Women?

Selenium is an essential trace element. Its intake and status in the blood plasma can vary considerably according to a number of factors [Duntas 2020]:

  • differences in diet and nutrition
  • differences in soil and plant selenium content
  • ethnic differences
  • genetic differences

Without a blood selenium test, it is not possible to know whether women planning a pregnancy have sufficient circulating selenium. The Mayo Clinic reports that the normal selenium concentration in adult human blood serum in the United States is 70 to 150 micrograms per liter with a population mean value of 98 micrograms per liter. read more

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IV Selenium Supplementation for Critically Ill Patients

Critically ill patient
Increased generation of harmful free radicals and increased systemic inflammation seem to play a direct role in cell death, increased morbidity, and higher mortality in critically ill patients. Selenium is a trace element that has cell regulatory, immunologic, and antioxidant and anti-inflammatory functions. Early selenium supplementation is a promising adjunctive therapy for critically ill patients.

Selenium supplementation – especially intravenous selenium supplementation – seems to be a promising adjuvant treatment for critically ill patients.

The aggregated results of a meta-analysis of the clinical outcomes of selenium supplementation on critically ill patients shows that intravenous selenium supplements as a single therapy can decrease the total mortality and can shorten the length of stay in hospital [Zhao 2019].

Furthermore, the results from the meta-analysis showed that the selenium supplementation did not increase the incidence of drug-induced side effects compared with the control group [Zhao 2019].

Selenium Supplementation for Critically Ill Patients – The Evidence

The researchers reviewed 19 randomized controlled trials enrolling 3341 critically ill patients. There were 1694 critically ill patients in the selenium supplementation group and 1647 critically ill patients in the control group. read more

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Selenium Supplementation and HIV Infections: A Review

Symptoms of AIDS
The six selenium and HIV infection studies show a beneficial effect of daily supplementation with 200 micrograms of selenium on immune function, in particular on CD4 white blood cell counts. The same beneficial effect on the immune system may be protective against other forms of infection, including against Covid-19 infections.

Six randomized controlled studies show that providing daily selenium supplementation to HIV-infected adults increases CD4 cell counts, reduces the risk of diarrhea morbidity, and lowers hospital admission rates for HIV-related conditions and opportunistic infection in HIV-infected adults [Kayode 2020].

Alexander et al [2020] have recognized the importance of selenium to immune system function and have recommended the initiation of adequate selenium supplementation in high-risk Covid-19 areas and as soon as possible after a suspected Covid-19 infection.

Richie et al [2014] have shown that selenium supplementation in the form of selenium-enriched yeast provides significantly greater protection against oxidative stress than supplementation with exclusively selenomethionine does. read more

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Selenium Supplementation and Blood Sugar Levels

Testing blood sugar
The results of randomized controlled trials of selenium supplementation show beneficial effects or no effect on blood sugar levels and insulin sensitivity values. In this review, we summarize the study results.

The effect of selenium supplementation on blood sugar levels and on the risk of diabetes is still an open question. However, the data from randomized controlled studies show that selenium supplementation is associated with either a beneficial effect or no effect at all on blood sugar levels, insulin sensitivity, and glucose tolerance [Jablonska 2016].

Study Participants with Type-2 Diabetes

Beneficial effect. In a 2019 study, the participants were 72 male and 22 female patients aged 48 to 64 years old with diabetes mellitus type 2. They were smokers, all of them, and they all followed a Mediterranean diet.

The researchers administered selenium 200 microg/day once daily on an empty stomach. The study data showed a statistically significant reduction in the blood levels of glucose and in HbA1c values at both three months and six months after the beginning of the treatment. The administration of selenium to type-2 diabetic patients seemed to improve the patients’ glycemic profile [Karalis 2019]. read more

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Selenium Supplementation and Prostate Cancer

New Zeland landscape
The New Zealand study results suggest that each of us needs to take personalized selenium supplement dosages based on our individual characteristics rather than have all of us take the same 200 microg/day tablet for prostate health benefits [Karunasinghe 2019].
Demographic, dietary, genetic, and life style factors influence the prostate health effects of selenium supplementation according to New Zealand researchers.

An inverse association between serum selenium concentrations and prostate-specific antigen levels was especially strong in the following sub-groups of study participants [Karunasinghe 2019]:

  • men below the age of 55 years
  • men who never smoked
  • men carrying the GPX1 rs1050450 T allele
  • men with dietary intakes above the recommended daily intake for zinc (11 mg)
  • men with dietary intakes below the recommended daily intake for vitamin B12 (15 mcg)

Moreover, the increase in serum selenium status and the resulting post-supplementation serum selenium status were significantly dependent upon baseline serum status [Karunasinghe 2019].

The overall gain in serum selenium levels from supplementation declined at a rate of 0.828 microg/L with each one microg/L increase in baseline serum selenium level [Karunasinghe 2019]. read more

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Selenium Status and Viral Infections

Selenium and viral infections, what do we know?

  • Selenium is a micronutrient that is essential for good health.
  • Low serum selenium status (below 85 microg/mL) and marginal serum selenium status (between 85 and 100 microg/mL) are common in many regions of the world, especially in many parts of Europe, the Middle East, China, and East Asia.
  • Selenium status is a key factor regulating the immune response to viral infections [Hiffler 2020].
  • Selenium status influences the immune system response to the severe acute respiratory syndrome corona virus infections [Bermano 2020].
  •  Selenium status is a risk factor that could well influence the outcome of a Covid-19 infection, particularly if the infected individuals have a sub-optimal or low selenium intake [Bermano 2020].
  • Selenium supplementation may limit the severity of Covid-19 infections, particularly in regions in which the selenium intake is low [Bermano 2020, Hiffler 2020].

Evidence for a Link Between Selenium Status and Viral Infection Severity

The early evidence came from study of the Keshan Disease in China – caused by the combination of the coxsackie B3 virus and low selenium status. By adding selenium to the soil fertilizer and by encouraging the use of selenium supplements, Chinese authorities have been able to reduce significantly the incidence of the disease [Bermano 2020].

Then came evidence from mouse studies that showed that there is increased virulence to coxsackie and influenza viruses in hosts with low selenium status [Bermano 2020].

Next came evidence that low selenium status, commonly seen in HIV-infected patients, is associated with reduced numbers of CD4 T cells and with increased disease progression and death rates [Bermano 2020]. read more

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Selenium, Selenoproteins, and Oxidative Stress

Disinfection materials
Low selenium status is associated with increased virulence of virus infections, with worse symptoms of heart failure, and with greater risk of some forms of cancer.

Oxidative stress is the bio-medical term for a lack of balance between 1) the production of harmful reactive oxygen and reactive nitrogen species and 2) the protective action of antioxidant systems. According to the news network of the Mayo Clinic, oxidative damage has been linked to several conditions such as Alzheimer’s, cancer, cataracts, diabetes, heart disease, macular degeneration, and Parkinson’s.

Free Radicals and Oxidative Damage

The reactive oxygen and reactive nitrogen species are popularly referred to as free radicals. They are molecules produced as natural by-products of metabolic processes and as a consequence of exposure to pollutants, to heavy metals, to industrial chemicals, to some drugs, to some forms of radiation including x-rays, and to cigarette smoking. read more

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Selenium Intakes and the Risk of Cancer: Two Meta-Analyses

Blue ribbon for prostate cancer
Despite the billions of dollars spent in the war on cancer, cancer in its various forms continues to be a leading cause of death worldwide. Treatment is expensive. The prognosis is often poor. Even so, the World Health Organization estimates that perhaps one third of all cancer cases could be prevented with changes in behavioral and dietary patterns. An inverse linear association has been found between increased selenium intake and reduced risk of all cancers. As the selenium intake increased, the overall risk of cancer incidence decreased [Kuria 2020].
A 2020 meta-analysis of population-based prospective studies shows that selenium supplementation is protective against cancer; however, the beneficial effects of the selenium supplementation vary with the different types of cancer. The differences in the effect of selenium intakes on the risk of various cancer forms has been attributed to differences in the pathophysiology of cancer [Kuria 2020].

Briefly, the data from the meta-analysis show that selenium decreases the risk of cancer at the highest daily intake levels of the included studies.

This outcome is consistent with the outcomes of a previous study showing a protective effect of selenium at high doses compared to low doses [Cai 2016]. A 2018 meta-analysis used different methods to assess selenium exposure and showed a null association between selenium at high doses compared to low doses [Vinceti 2018]. read more