Selenium

Selenium is a trace mineral that is naturally found in certain foods and tiny amounts in water. An essential mineral for our body, selenium plays crucial parts in many bodily functions, such as increasing immunity, improving cognitive function, and boosting fertility in both men and women. 

In our body, selenium can be found in the tissue, mostly in skeletal muscle. Our bodies contain about 14 mg of selenium. Each cell contains more than a million selenium atoms. 

 5 Musculoskeletal Benefits of Selenium

1. Selenium is a Potent Antioxidant

Selenium acts as a co-factor for glutathione peroxidase. Glutathione peroxidase is one of the body’s cardinal detoxifying anti-oxidants. Glutathione peroxidase’s primary task is neutralize hydrogen peroxide before it can damage healthy tissue.

Selenium also functions as a primary component of thioredoxin reductase. Thioredoxin reductase helps to reprocess Vitamin E and Vitamin C. Vitamin C and Vitamin E are critical vitamins in the fight against free radicals.

 

2.  Selenium Promotes Bone Health

Selenium is a powerful anti-oxidant. Excessive oxidative stress causes bone resorbing cells, called osteoclasts, to produce more free radicals and to resorb more bone. Bone loss is the hallmark of osteoporosis.  Healthy amounts of selenium helps restore the bone’s natural anti-oxidant defenses, helps reduce inflammation, and helps diminishes unhealthful osteoclast activity.

 

A large study  of 2,374 euthyroid post-menopausal women showed that higher selenium levels positively correlated with better hip and/or lumbar spine bone density.(HOEG A, GOGAKOS A, MURENY E, MUELLER S, KÖHRLE J, REID DM, GLÜER CC, FELSENBERG D, ROUX C, EASTELL R, SCHONBURG L, WILLIAMS GR: Bone turnover and bone mineral density are independently related to selenium status in healthy euthyroid postmenopausal women. Clin Endocrinol Metab 97: 4061-4070, 2012.)

3. Selenium Supports Tendon health

Selenium’s anti-oxidant attributes help suppress powerful inflammatory pathways. Scientific evidence suggests chronic inflammation contributes to the degradation and dysfunction of tendons. Unhealthy inflammation leads to the release of tissue destroying enzymes and the  sensitization of pain receptors. Functionally, the tendon becomes a painful, disorganized ball of scar with inferior mechanical properties, such as decreased strength and flexibility.

4. Selenium Boosts Joint Health

Oxidative stress is a known risk factor for chronic joint disease. Free radical damage initiates a chain reaction that results in irreparable changes to the normal architecture of cartilage and the layer of bone just beneath cartilage, called subchondral bone. With these changes, the joint can no longer perform its shock absorbing function. Selenium’s protection against oxidative stress helps shield the joint from these undesirable attributes.

 

The clue regarding selenium’s role in osteoarthritis can be gleaned from a rare ailment called Kashin‐Beck disease. This disease is endemic to certain areas of China, Tibet, and Siberia. This malady has all the hallmarks of osteoarthritis: pain, stiffness, weakness, and joint destruction. Glaring selenium deficiency is a distinct feature of dietary patterns of peoples in these regions. Scientists after consideration all possible contributing factors, suggest a selenium deficient diet play a significant role in the onset and propagation of this disease.(Wu, S. X., Wang, W. Z., Zhang, F., Wu, C. Y., Dennis, B. S., Qu, C. J., & … Guo, X. (2014). Expression profiles of genes involved in apoptosis and selenium metabolism in articular cartilage of patients with Kashin-Beck osteoarthritis. Gene, 535(2), 124-130. doi:10.1016/j.gene.2013.11.050)

5.  Selenium Promotes Muscle Health

Sarcopenia is defined as a progressive loss of muscle mass and commonly occurs as we age. Chronic inflammation and free radical injury are thought to play a central role in sarcopenia’s manifestation and progression. Selenium deficiency has been associated with sarcopenia. Selenium’s robust anti-oxidation and anti-inflammatory attributes promotes healthy muscle mass.

 

In a recent review, Danish research analyzed over 3000 articles investigating minerals and sarcopenia. Selenium was associated with increased muscle mass and physical performance. (Van Dronkelaar et al. Minerals and Sarcopenia; The Role of Calcium, Iron, Magnesium, Phosphorus, Potassium, Selenium, Sodium, and Zinc on Muscle Mass, Muscle Strength, and Physical Performance in Older Adults: A Systematic Review. J Am Med Dir Assoc. 2017 Jul 12. pii: S1525­8610(17)30305­5.)

Other Health Benefits 

There are other conditions that selenium may assist, although more research is needed and for some conditions results to date have been mixed. Those include:

  • Boosts Immune System
  • Supports Healthy Thyroid Function
  • Improves blood flow and lowers chances of heart disease
  • Boosts fertility

 

Best Sources of Selenium 

Seafoods and meats are the richest food sources of selenium. The amount of selenium in a given type of plant-based food and grain depends on the amount of selenium in the soil.

Recommended Dietary Allowance (RDA)

The Food and Nutrition Board has developed a table of recommended daily allowances (RDAs) of selenium, based on age and gender. The values are:

Age                       Male                   Female             Pregnant       Breastfeeding

0 to 6 months        15 mcg/day     15 mcg/day         

7 to 12 months      20 mcg/day      20 mcg/day         

1 to 3 years           20 mcg/day      20 mcg/day         

4 to 8 years           30 mcg/day      30 mcg/day         

9 to 13 years         40 mcg/day       40 mcg/day         

14 to 18 years       55 mcg             55 mcg                60 mcg          70 mcg

19 to 50 years       55 mcg             55 mcg                60 mcg          70 mcg

51+ years              55 mcg             55 mcg         

 

Precautions

Selenium from natural foods is generally well tolerated. RDA amounts can usually be obtained from a balanced, healthful diet.

An upper limit of 400 mcg/day has been recommended by the National Academy of Sciences. Common symptoms of chronically high intakes of selenium are a garlic like odor in breath, metallic taste in mouth, hair and nail loss.

Any consideration of supplementation should be discussed with a qualified health professional familiar with your unique medical history. 

References

(2016). Selenium: Fact sheet for health professionals. National Institutes of Health. Retrieved from https://ods.od.nih.gov/factsheets/Selenium-HealthProfessional/

(2017). Periodic table: Selenium. Royal Society of Chemistry. Retrieved from http://www.rsc.org/periodic-table/element/34/selenium

(2017). Selenium. Micronutrient Information Center. Retrieved from http://lpi.oregonstate.edu/mic/minerals/selenium

(2017). Selenium. The World’s Healthiest Foods. Retrieved from http://www.whfoods.com/genpage.php?dbid=95&tname=nutrient

Canter, P. H., Wider, B., & Ernst, E. (2007). The antioxidant vitamins A, C, E and selenium in the treatment of arthritis: A systematic review of randomized clinical trials. Rheumatology, 46(8), 1223-1233. https://doi.org/10.1093/rheumatology/kem116

Frestedt, J. L., Kuskowski, M. A., & Zenk, J. L. (2009). A natural seaweed derived mineral supplement (Aquamin F) for knee osteoarthritis: A randomised, placebo controlled pilot study. Nutrition Journal, 8(7). doi:10.1186/1475-2891-8-7

Kurz, B., Jost, B., & Schünke, M. (2002). Dietary vitamins and selenium diminish the development of mechanically induced osteoarthritis and increase the expression of antioxidative enzymes in the knee joint of STR/1N mice. Osteoarthritis and Cartilage, 10(2), 119-126. http://dx.doi.org/10.1053/joca.2001.0489

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Ren, F. L., Guo, X., Zhang, R. J., Wang, S. H, J., Zuo, H., Zhang, Z. T. (2007). Effects of selenium and iodine deficiency on bone, cartilage growth plate and chondrocyte differentiation in two generations of rats. Osteoarthritis and Cartilage, 15(10), 1171–1177. http://dx.doi.org/10.1016/j.joca.2007.03.013

Wu, S. X., Wang, W. Z., Zhang, F., Wu, C. Y., Dennis, B. S., Qu, C. J., & … Guo, X. (2014). Expression profiles of genes involved in apoptosis and selenium metabolism in articular cartilage of patients with Kashin-Beck osteoarthritis. Gene, 535(2), 124-130. doi:10.1016/j.gene.2013.11.050

Yazar, M., Sarban, S., Kocyigit, A., & Isikan, U. E. (2005). Synovial fluid and plasma selenium, copper, zinc, and iron concentrations in patients with rheumatoid arthritis and osteoarthritis. Biol Trace Elem Res, 106(2), 123-32. doi:10.1385/BTER:106:2:123

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 Lucas J. Bader MD

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