Tag: Cancer

Posted on

Impact of Selenium Status on Biological Aging

Aging. Getting up in years. Striving to live as long as possible and to be as strong and healthy as possible. At some point, good health becomes a more important concern than wealth. Optimal selenium status is important to good health [Alehagen 2021].

Professor Jan Aaseth
Professor Jan Aaseth, MD, PhD, researcher in internal medicine, endocrinology, and toxicology and specialist in selenium research.

In a review article, Professor Urban Alehagen and Professor Jan Aaseth list the following conditions associated with biological aging [Alehagen 2021]:

  • chronic mild to moderate systemic inflammation
  • detrimental DNA alterations
  • mitochondrial dysfunction
  • oxidative stress caused by harmful free radicals
  • telomere shortening

Getting old is inevitable. Biological aging necessarily involves a weakening of the immune system and increased susceptibility to diseases and environmental stresses.

Selenium deficiency associated with aging and aging-related diseases

Selenium deficiency is associated with mitochondrial dysfunction, oxidative stress, and inflammation [Alehagen 2021].

Mitochondrial injuries are an important factor in the aging of human cells.  A by-product of the mitochondrial generation of ATP energy in the cells is the production of reactive oxygen species, some of which are useful and some of which are harmful. The leakage of these harmful free radicals from the mitochondrial respiratory chain increases with age, which results in cellular oxidative damage, whenever there are not enough antioxidants to neutralize the effects of the free radicals. read more

Posted on

Breast Cancer Recurrence and Selenoprotein P Autoimmunity

Breast cancer prognosis is especially poor in patients with low serum selenium and serum selenoprotein P concentrations. Now, researchers have discovered natural autoantibodies with antagonistic properties to selenoprotein P uptake in breast cancer patients and  in patients with thyroid disease [Demircan 2022; Sun 2022].

Autoimmunity
Autoimmunity is the production of antibodies against the tissues or substances of one’s own body, resulting in an autoimmune disease or hypersensitivity reaction. Autoantibodies to Selenoprotein P impair the transport of the essential trace element selenium in breast cancer patients and in Hashimoto’s thyroiditis patients.

Selenium is an essential trace element that has numerous biological functions in the body, most of which are carried out by selenium-containing selenoproteins. Among the more important selenoproteins are selenoprotein P, the main transporter of selenium in the blood, and glutathione peroxidase 3 (GPX3), an important antioxidant.

The human body does not synthesize selenium. Human cells are dependent upon selenium sources in the diet. Unfortunately, the selenium content in the soil and in food varies considerably from region to region in the world. For example, the plasma selenium concentrations in people living in much of Europe are generally below, often well below, 80–90 mcg/L whereas people living in North America generally have plasma selenium levels above 120 mcg/L [Alehagen 2022]. read more

Posted on

Selenium Exposure Studies

Selenium exposure in the diet and in supplements: in this review article, we summarize the key outcomes of the best selenium exposure studies.

Optimal Selenium Intake and Status

In his review of the available research literature, Professor Urban Alehagen, Linköping University, Sweden, concluded that a daily intake of 100–150 mcg of selenium per day is required.

This is the intake level that enables an optimal expression of the important selenoprotein P that transports selenium from the liver to peripheral tissues [Alehagen 2022].  For other selenoproteins to be optimized, i.e., to be fully expressed, Prof. Alehagen argues that selenium status of approximately 120 mcg/L when measured in red blood cells is necessary [Alehagen 2022]. read more

Posted on

Serum Selenium Levels Predict Breast Cancer Prognosis

Research done in southern Sweden shows that three blood biomarkers of selenium availability correlated inversely with mortality from breast cancer. The lower the three selenium biomarker levels, the higher the mortality [Demircan 2021].

Breast cancer awareness
Assessment of selenium status at the time of breast cancer diagnosis identifies patients at exceptionally high risk for a poor prognosis. They are breast cancer patients with low levels of selenium, selenoprotein P, and glutathione peroxidase in their blood.

The blood biomarkers are:

  • Total selenium
  • Selenoprotein P
  • Glutathione peroxidase 3

Breast cancer patients with blood concentrations of these three selenium biomarkers in the highest quintile had significantly better chances of survival compared with patients whose blood levels of these substances were in the lowest quintile [Demircan 2021].

Breast cancer patients with low selenium status according to these three biomarkers had the highest mortality risk with an overall survival probability of approximately 50% after 8 years. The difference in survival between the breast cancer patients in the lowest selenium quintile compared to breast cancer patients with at least one biomarker in the highest quintile was especially notable [Demircan 2021]. read more

Posted on

Impact of Selenium Status on Ageing

Selenium is an essential trace element. Essential means that sufficient selenium is necessary for normal cell functioning and that our bodies cannot synthesize selenium for us. We must get it from our diets. Trace element means selenium is a micronutrient that is needed in very small quantities, in microgram quantities. It may be an important element to slow the ageing process.

Elderly couple
Selenium as a component in protective enzymes helps to keep us healthier longer in life. It helps to suppress oxidative stress and to decrease inflammation, to remove misfolded proteins, to decrease DNA damage, and to promote telomere length.

Sufficient selenium status plays an important role in the prevention of cardiovascular diseases, inflammation, and infections. Prof. Margaret P. Rayman, University of Surrey, estimates that serum/plasma selenium status of around 125 mcg/L is optimal for human health [Rayman 2020].

The beneficial work of selenium in the cells and tissues is done by selenoproteins that contain the amino acid selenocysteine in the active center. Among the selenoproteins known to have an antioxidant effect in the body are the glutathione peroxidases (GPX1-4 and GPX6) and the thioredoxin reductases (TXNRD1-3) [Alehagen 2021]. read more

Posted on

Selenium and Immune Function and DNA Repair

Selenium is a trace element essential for for DNA repair, for  good immune function, and for reduced mortality risk.

DNA double helix
Cell studies, animal models, and human clinical trials suggest that an optimal supply of selenium is required to enhance the process of DNA damage repair.

The Micronutrient Information Center maintained by staff members at the Linus Pauling Institute of the Oregon State University provides reliable information about the vitamins and minerals and trace elements used in nutritional supplements.

Today, I want to summarize the information that the Center provides about selenium and supplement that information with the latest scientific research.

An Introduction to Selenium and Selenoproteins

Selenium is a trace element that is essential that humans need for the proper functioning of selenium-dependent selenoproteins. Free selenium is rare in the body. Instead, the selenium in the body is typically a component of selenomethionine, selenocysteine, and methyl-selenocysteine. read more

Posted on

Selenium and cancer prevention: The Linxian Study

In the 1990s and before, the diets of the people in the Linxian province in China were poor in important micronutrients. Selenium status among the residents was notably low. Cancer rates were high. Supplementation with selenium and other antioxidants reduced cancer incidence and mortality.

The Nutrition Intervention Trials conducted in the Linxian province in China yielded some of the first promising results linking selenium supplementation to the reduction of cancer incidence and mortality.  The Linxian province at the time was characterized by a selenium-poor diet.

The treatment group that received selenium supplements was the group that showed significant health benefits of the supplementation:

  • Significantly lower total mortality
  • Significantly lower cancer mortality
  • Significantly lower stomach cancer mortality

The reduced mortality rates began to become apparent already after 1 – 2 years of supplementation.  The patterns for reductions in cancer incidence generally approximated the patterns for cancer mortality [Blot].

The Linxian study results were exciting because they were published in the Journal of the National Cancer Institute and because they appeared before the results of the Nutritional Prevention of Cancer study in the United States [Clark]. read more

Posted on

Selenium and reduced risk of cancer

The results of Dr. Larry Clark’s Nutritional Prevention of Cancer trial showed the efficacy of selenium supplementation in reducing the risk of cancer: colon cancer, lung cancer, and prostate cancer. Now, a meta-analysis of 69 studies shows that higher selenium exposure is associated with reductions in the risk of breast cancer, lung cancer, and prostate cancer.

Authors of a recent meta-analysis of 69 studies of selenium exposure and cancer risk have concluded that high selenium exposure can reduce cancer risk, especially high selenium exposure that is reflected in high plasma or serum selenium status and/or in high toenail concentrations [Cai 2016].  Admittedly, higher selenium intakes (as compared to lower selenium intakes) can affect different forms of cancer differently.  We still need more research to sort out which forms and dosages of dietary and supplemental selenium are most effective at reducing cancer risk.  In this article, I want to summarize the findings of Dr. Xianlei Cai and colleagues.

What is a meta-analysis of selenium exposure and cancer risk?
A meta-analysis is a research method of combining the data from several selected research studies to reach conclusions that have greater statistical power.  In the present case, Cai et al selected 69 studies that met their inclusion criteria.  Each one of the 69 selected studies had the following characteristics:

  • was a randomized controlled trial or a cohort study or a case-control study
  • considered selenium as a baseline exposure and cancer risk as an outcome
  • was published in English between 1980 and 2014
  • contained the necessary data for the meta-analysis

The 69 studies contained the data from 364,742 study participants with 26,138 cancer events.  This was some serious number-crunching.  For all of the results that follow, the researchers first checked to make sure that such variables as exposure mode, geographic region, and study design were not influencing the results independently.  They also checked for a gender difference in the effect of selenium exposure and found no significant effect of gender. read more

Posted on

Selenium Compounds Fight Cancer

diabetes-picture, cancer
The body’s selenium level can be measured by using a blood sample. Some selenium compounds fight some forms of cancer.

In a new scientific study, Danish researchers from Copenhagen University have demonstrated that methylated selenium compounds can regulate the body’s immune system enabling it to better fight certain cancers. These selenium compounds are found in certain foods such as garlic and broccoli but also in the selenium preparations containing selenium yeast.

Certain cancers, e.g., in the skin, in the prostate, and in some forms of leukemia, weaken the body’s immune system by overstimulating it until it eventually breaks down, giving cancerous cells a free rein in the body. What this new Danish research shows is that the intake of selenium compounds that can be metabolized into methylselenol improves the immune system’s ability to fight cancer. read more