Selenium is a trace mineral with crucial properties. It controls several processes in normal health and metabolism. The mineral promotes thyroid health and plays a role in maintaining cardiovascular and neurological health (1).
But a deficiency of this mineral can have serious consequences. Reports suggest that selenium deficiency affects close to a billion people in the world (2).
In this post, we will discuss the grave effects selenium deficiency can have on your health, and more importantly, what you can do to prevent them.
What Is Selenium Deficiency?
Selenium deficiency refers to having inadequate levels of the mineral in your system. This can happen due to the diminishing levels of selenium in the soil where foods rich in selenium are grown.
Insufficient intake of selenium can alter the way certain selenium-responsive enzymes function. These enzymes include glutathione peroxidases, iodothyronine deiodinases, and selenoproteins (3).
Individuals deficient in selenium were found to be more vulnerable to physiological stresses (3). Selenium deficiency, as we discussed, can cause more harm than you might know. In the following section, we will explore how.
What Are The Signs And Symptoms Of Selenium Deficiency?
Selenium deficiency can surface in the form of muscle weakness, anxiety, depressed mood, and confusion. These symptoms, if ignored, can lead to more complicated health risks (1).
1. Can Cause Cardiovascular Problems
Selenium deficiency was linked to cardiomyopathy, which is a chronic disease of the heart muscle. Studies have also shown it to cause Keshan disease, a form of cardiomyopathy prevalent in the Chinese county of Keshan (4). In mice studies, selenium supplementation could reduce cardiotoxicity (5).
Selenium is known to combat oxidative stress. Its deficiency can potentially lead to an increase in oxidative stress, thereby possibly affecting heart health (5).
Selenium deficiency in rats also led to increased myocardial damage. Studies conclude that low serum selenium levels can be considered a risk factor for cardiovascular disease (5).
Deficiency of the mineral may also cause lipid peroxidation (degradation of lipids). This can cause elevated blood pressure levels and platelet aggregation, potentially increasing heart disease risk. Adequate selenium levels also protect the heart from certain viral infections (6).
2. Can Affect The Endocrine System
The endocrine system regulates hormones that promote growth, development, and metabolism (7). It includes the thyroid, pituitary, and adrenal glands, the pancreas, testicles (male), and ovaries (female) (8).
The thyroid contains the maximum concentration of selenium among all organs of the human body. Iodothyronine deiodinases, the enzymes associated with selenium, promote thyroid hormone metabolism (1). Deficiency of selenium can obstruct this process.
Selenium controls the functioning of over 30 different selenoproteins, all of which exert multiple actions on the endocrine system. These selenoproteins act as antioxidants and modify the cell function in the system (9).
3. Can Harm The Musculoskeletal System
Selenium deficiency can cause musculoskeletal diseases. One of them is the Kashin-Beck disease, which is characterized by the deformity of bones, cartilages, and joints. This leads to enlarged joints and restricts movement (1).
Selenium and the associated selenoproteins also have a role to play in muscular function. In both cattle and humans, selenium deficiency was observed to cause several muscular diseases (10).
4. May Affect Neural Health
Selenium deficiency has been found to cause depressive mood and hostile behavior. The deficiency can also affect the turnover rate of certain neurotransmitters (1).
In patients with Alzheimer’s, selenium concentration was found to be only 60% of that of healthy individuals (1).
Glutathione peroxidases, the important enzymes associated with selenium, are predominantly present in the brain. These enzymes reduce the reactive oxygen species, which can damage brain health. Deficiency in selenium can hamper this beneficial process (11).
5. Can Hurt Your Immune System
Reports have linked selenium deficiency to weak immunity. The mineral may improve response, and its inadequacy may weaken the immune system (1).
Selenium deficiency was also found to impair immune response and increase the risk of infection (12). Dietary selenium is important for a healthy immune system.
Selenium deficiency may also lead to the dysfunction of immune cells (13).
6. May Affect The Reproductive System
In males, selenium plays a role in testosterone biosynthesis. Deficiency of selenium may cause infertility in males (1).
Selenium deficiency in females may also lead to infertility issues. However, more large-scale studies are needed to conclude this (14).
Selenium deficiency can have fatal consequences in the long run. It is important to understand if you are at risk. Certain individuals tend to be at a higher risk of the deficiency than others.
Who Is At A Higher Risk Of Selenium Deficiency?
Though selenium deficiency is quite rare in the United States, certain groups of people can be at a higher risk.
- Those Undergoing Kidney Dialysis
Kidney dialysis (also known as hemodialysis) removes some selenium from the blood (15). Patients undergoing dialysis could also be selenium deficient due to severe food restrictions.
Individuals living with HIV may become selenium deficient due to excessive loss of the nutrient through diarrhea. Even malabsorption can lead to deficiency. Serum selenium levels can decrease with disease progression (16).
- Those Living In Selenium-Deficient Regions
Individuals living in countries whose diet has vegetables grown in low-selenium areas can also be at risk of selenium deficiency. These include certain parts of China, where soil selenium levels are low (17). Even individuals living in some European countries could be at risk.
If you belong to the risk groups or experience symptoms associated with selenium deficiency, please visit your doctor. Any delays can have serious consequences.
How Is The Deficiency Diagnosed?
Selenium deficiency is diagnosed and confirmed by measuring concentrations of the mineral in the serum or plasma. Selenium levels less than 70 bg/mL indicate the possibility of deficiency.
What About The Treatment?
Most often, selenium deficiency affects entire populations. Soils have been fertilized and foods have been fortified with selenium (1).
The best treatment for individuals deficient in selenium is following a selenium-rich diet. Foods rich in selenium include:
- Brazil nuts
- Yellowfin tuna
- Beef liver
- Cottage cheese
- Brown rice
If you cannot consume any of the selenium-rich foods for any reason, selenium supplements can also help (3). Ensure you speak to your health care provider before going for supplements to avoid selenium toxicity.
It could be a trace mineral. But it is important to understand how much selenium we need. For adults (both male and female), the RDA for selenium is 55 mcg. For pregnant women, it is 60 mcg per day, while for lactating women, it is 70 mcg per day. The tolerable upper limit for selenium is 400 mcg per day. Intakes beyond this can cause problems (17).
Since selenium happens to be a trace mineral, we do not pay it much attention. But as we have seen, it has some very important roles to play in human health. Its deficiency can cause serious health issues.
If you experience symptoms that could be related to selenium deficiency, please visit your doctor. Start including foods/supplements in your diet as required.
Were you deficient on selenium before? What measures did you take? Do share your experiences with us by leaving a comment in the box below.
- Selenium Deficiency, National Center for Biotechnology Information.
- Selenium deficiency risk predicted to increase under future climate change, Proceedings of the National Academy of Sciences of the United States of America.
- Selenium, Oregon State University.
- Is selenium deficiency really the cause of Keshan disease? Environmental Geochemistry and Health, US National Library of Medicine, National Institutes of Health.
- Selenium and Its Supplementation in Cardiovascular Disease—What do We Know? Nutrients, US National Library of Medicine, National Institutes of Health.
- Selenium and cardiovascular disease, Biological Trace Element Research, US National Library of Medicine, National Institutes of Health.
- Introduction to the Endocrine System, National Cancer Institute, National Institutes of Health.
- Endocrine system, US National Library of Medicine, National Institutes of Health.
- Selenium and endocrine systems, The Journal of Endocrinology, US National Library of Medicine, National Institutes of Health.
- Understanding the importance of selenium and selenoproteins in muscle function, Cellular and Molecular Life Sciences, US National Library of Medicine, National Institutes of Health.
- Cognitive function in depth, Oregon State University.
- Selenium deficiency impairs host innate immune response and induces susceptibility to Listeria monocytogenes infection, BMC Immunology, US National Library of Medicine, National Institutes of Health.
- Selenium deficiency inhibits differentiation and immune function and imbalances the Th1/Th2 of dendritic cells, Metallomics, US National Library of Medicine, National Institutes of Health.
- Selenium, Selenoproteins, and Female Reproduction: A Review, Molecules, US National Library of Medicine, National Institutes of Health.
- Trace elements in hemodialysis patients: a systematic review and meta-analysis, BMC Medicine, US National Library of Medicine, National Institutes of Health.
- Role of selenium in HIV infection, Nutrition Reviews, US National Library of Medicine, National Institutes of Health.
- Selenium, National Institutes of Health, Office of Dietary Supplements.