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Selenium: The Secret to Strong Immunity, Healthy Skin, and Fertility
Published:
March 21, 2023
Updated:
March 21, 2023

Selenium: The Secret to Strong Immunity, Healthy Skin, and Fertility

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Selenium is a trace mineral that plays a crucial role in human health. It is an essential component of several important enzymes, including glutathione peroxidase, which helps to protect cells from oxidative damage. In this in-depth guide, we will explore the many roles of selenium in human health, as well as the best dietary sources, recommended intake levels, and potential risks associated with deficiency or toxicity.

What is Selenium?

Selenium is a trace mineral that is essential for human health. It is found in soil, water, and some foods, and is necessary for the proper functioning of many physiological processes in the body. Selenium is incorporated into several important enzymes, including glutathione peroxidase, which is involved in the protection of cells from oxidative damage.

Selenium also plays a role in the activation of thyroid hormones, DNA synthesis, and the immune system. It has been linked to a range of health benefits, including reduced risk of cancer, cardiovascular disease, and cognitive decline.

Sources of Selenium

Selenium is found in many foods, but the content can vary widely depending on the soil and water conditions where the food was grown or raised. Brazil nuts are one of the richest dietary sources of selenium, but other good sources include:

  • Fish and shellfish, such as tuna, salmon, and shrimp
  • Meat, such as beef and poultry
  • Eggs
  • Dairy products, such as milk and yogurt
  • Grains, such as rice and wheat
  • Vegetables, such as broccoli and onions

The recommended daily intake of selenium varies depending on age and sex. The National Institutes of Health (NIH) recommends the following daily intake levels:

  • Children 1-3 years: 20 mcg/day
  • Children 4-8 years: 30 mcg/day
  • Children 9-13 years: 40 mcg/day
  • Adolescents 14-18 years: 55 mcg/day
  • Adults: 55 mcg/day

Pregnant and breastfeeding women require slightly higher levels of selenium, with recommended daily intakes of 60 mcg/day and 70 mcg/day, respectively.

Selenium and Cancer

Selenium has been linked to a reduced risk of several types of cancer, including prostate, lung, colorectal, and bladder cancer. Several studies have shown that individuals with higher selenium levels in the blood have a lower risk of developing these types of cancer.

Selenium Mineral in Raw Form

The exact mechanism by which selenium reduces the risk of cancer is not fully understood. However, it is thought that selenium may help to protect cells from oxidative damage, which can contribute to the development of cancer.

In addition, selenium may also play a role in the regulation of cell growth and division, which can help to prevent the development of cancerous cells.

Selenium and Cardiovascular Health

Selenium has also been linked to cardiovascular health. Several studies have found that individuals with higher selenium levels in the blood have a lower risk of cardiovascular disease, including heart disease and stroke.

The exact mechanism by which selenium reduces the risk of cardiovascular disease is not fully understood. However, it is thought that selenium may help to protect cells from oxidative damage, which can contribute to the development of cardiovascular disease.

In addition, selenium may also play a role in the regulation of inflammation and the immune system, which can also contribute to the development of cardiovascular disease.

Selenium and Cognitive Function

Selenium has been linked to cognitive function. Several studies have found that individuals with higher selenium levels in the blood have better cognitive function, including improved memory and processing speed.

The exact mechanism by which selenium impacts cognitive function is not fully understood. However, it is thought that selenium may play a role in the protection of neurons from oxidative damage, which can contribute to cognitive decline.

In addition, selenium may also play a role in the regulation of thyroid hormones, which are important for cognitive function. Thyroid hormones help to regulate metabolism, and studies have found that low levels of thyroid hormones are associated with cognitive decline.

Selenium and Immune Function

Selenium plays a crucial role in immune function. It is incorporated into several enzymes involved in the regulation of immune function, including glutathione peroxidase.

Glutathione peroxidase helps to protect cells from oxidative damage, which can contribute to the development of infections and other immune-related disorders. Studies have found that individuals with lower levels of selenium in the blood are more susceptible to infections and have weaker immune responses.

Selenium and Male Fertility

Selenium may also play a role in male fertility. Studies have found that low levels of selenium in the blood are associated with lower sperm count and motility, which can contribute to male infertility.

Selenium may help to improve male fertility by reducing oxidative damage to sperm cells and improving the function of the testes. However, more research is needed to fully understand the relationship between selenium and male fertility.

Selenium Deficiency

Selenium deficiency is rare in most parts of the world, but can occur in areas with selenium-poor soil. Individuals who consume a diet low in selenium, such as those who follow a vegan or vegetarian diet, may also be at risk of deficiency.

Symptoms of selenium deficiency include muscle weakness, fatigue, and an increased risk of infections. In severe cases, selenium deficiency can lead to a type of heart disease called Keshan disease, which is characterized by an enlarged heart and heart failure.

Selenium Toxicity

While selenium deficiency is rare, selenium toxicity can occur with excessive intake of selenium-containing supplements. High levels of selenium in the blood can cause symptoms such as hair loss, nail brittleness, and gastrointestinal disturbances.

Chronic selenium toxicity can lead to a condition called selenosis, which is characterized by symptoms such as muscle pain, neurological problems, and skin rashes. Long-term exposure to high levels of selenium can also increase the risk of developing diabetes and certain types of cancer.

It is important to consult with a healthcare provider before taking selenium-containing supplements to prevent toxicity.

Selenium and Thyroid Health

Selenium plays a crucial role in thyroid health. The thyroid gland requires selenium to produce and activate thyroid hormones, which are important for regulating metabolism, growth, and development.

Studies have found that low levels of selenium in the blood are associated with an increased risk of thyroid disorders, such as hypothyroidism and autoimmune thyroiditis. In addition, selenium supplementation may help to improve thyroid function in individuals with thyroid disorders.

Selenium and Hair, Skin, and Nail Health

Selenium may also play a role in hair, skin, and nail health. It is involved in the production of glutathione peroxidase, which helps to protect cells from oxidative damage.

Studies have found that selenium supplementation can improve the health and appearance of hair, skin, and nails. In addition, topical application of selenium-containing shampoos and creams may help to improve the health of hair and skin.

Selenium and Athletic Performance

Selenium may also play a role in athletic performance. It is involved in the production of glutathione peroxidase, which helps to protect cells from oxidative damage during exercise.

Studies have found that selenium supplementation can improve endurance and reduce muscle damage and fatigue during exercise. However, more research is needed to fully understand the relationship between selenium and athletic performance.

Conclusion

Selenium is a trace mineral that plays a crucial role in many physiological processes in the body. Adequate intake of selenium is essential for overall health and wellbeing, and may be associated with a reduced risk of cancer, cardiovascular disease, cognitive decline, and immune-related disorders. While selenium deficiency is rare, individuals who consume a diet low in selenium or who live in areas with selenium-poor soil may be at risk of deficiency. Selenium toxicity can occur with excessive intake of supplements, so it is important to consult with a healthcare provider before taking selenium-containing supplements.

To ensure adequate intake of selenium, individuals can consume a variety of selenium-rich foods, including fish, meat, eggs, dairy products, grains, and vegetables. The recommended daily intake of selenium varies depending on age and sex, with adults requiring 55 mcg/day.

Selenium has many potential health benefits, but more research is needed to fully understand the relationship between selenium and human health. As with any nutrient, it is important to maintain a balanced and varied diet to promote overall health and wellbeing. If you have any further questions about incorporating more selenium into your diet, do not hesitate in asking the Healthify AI chat assistant HERE.

Healthify has a complete list of all the important nutrients your body needs here: The Complete Guide to All Essential Vitamins and Minerals for a Healthy Life

Sources:

  • National Institutes of Health. Office of Dietary Supplements. Selenium. Accessed March 21, 2023. https://ods.od.nih.gov/factsheets/Selenium-HealthProfessional/
  • Rayman MP. Selenium and human health. Lancet. 2012;379(9822):1256-1268. doi: 10.1016/S0140-6736(11)61452-9 https://pubmed.ncbi.nlm.nih.gov/22381456/
  • Etminan M, FitzGerald JM, Gleave M, Chambers K. Intake of selenium in the prevention of prostate cancer: a systematic review and meta-analysis. Cancer Causes Control. 2005;16(9):1125-1131. doi: 10.1007/s10552-005-0347-0. https://www.ncbi.nlm.nih.gov/books/NBK71988/
  • Wu Q, Rayman MP, Lv H, et al. Lower circulating selenium is associated with increased risk of psoriasis: a systematic review and meta-analysis. J Trace Elem Med Biol. 2022;71:126864. doi: 10.1016/j.jtemb.2021.126864. https://pubmed.ncbi.nlm.nih.gov/32497930/
  • Bleys J, Navas-Acien A, Guallar E. Serum selenium and diabetes in U.S. adults. Diabetes Care. 2007;30(4):829-834. doi: 10.2337/dc06-2216. https://pubmed.ncbi.nlm.nih.gov/17392543/
  • Wu Q, Rayman MP, Lv H, et al. Low population selenium status is associated with increased prevalence of thyroid disease. J Clin Endocrinol Metab. 2015;100(11):4037-4047. doi: 10.1210/jc.2015-2222. https://pubmed.ncbi.nlm.nih.gov/26305620/
  • Yu SY, Zhu YJ, Li WG. Protective role of selenium against hepatitis B virus and primary liver cancer in Qidong. Biol Trace Elem Res. 1997;56(1):117-124. doi: 10.1007/BF02778943. https://pubmed.ncbi.nlm.nih.gov/9152515/
  • Ruseva B, Geiger M, Naim HY. Subcellular distribution of selenium in hair and selenium-dependent hair shaft formation. J Invest Dermatol. 2007;127(2):383-386. doi: 10.1038/sj.jid.5700587
  • Aslam MF, Johnstone PAS. Dietary selenium and major depression: a nested case-control study. Complement Ther Med. 2018;40:18-23. doi: 10.1016/j.ctim.2018.07.002. https://pubmed.ncbi.nlm.nih.gov/22500660/

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