Senior man playing chess with whole body support with selenium


Selenium protects against DNA damage, removes toxins, and maintains immune activity.

Scientifically reviewed by: Dr. Gary Gonzalez, MD, in December 2022. Written by: Laurie Mathena.

When researchers studied a population of people 90 years old and above, they found that the OLDEST inhabitants—those over 100 years old—all had something in common: They had the highest levels of the trace mineral selenium.1

There’s a reason selenium levels are connected to longevity. Selenium is required for the proper function of cellular enzymes.2

Past studies have shown that selenium-containing proteins provide defense against DNA damage,3,4 facilitate removal of toxins from the body,5 support thyroid function,6 and maintain immune system activity.7,8

The science about selenium continues to stack up. Here, we report on recent selenium studies.

Benefits of Boosting Selenium Intake

Selenium, in combination with other antioxidants, helps reduce risk of death.9

In a meta-analysis of 43 studies, researchers found a decreased risk of cardiovascular mortality and all-cause mortality when selenium was included in antioxidant supplement mixtures. No association was seen when selenium was absent from the mix.

Protecting Against Radiation

Selenium reduces side effects of radiotherapy. 10

After reviewing six studies, researchers found that selenium intake (300-500 mcg/day for 10 days to 6 months) reduced the side effects of radiotherapy without reducing effectiveness.

Researchers recommended that cancer patients who are deficient in selenium consider supplementation.

Risks Associated with Selenium Deficiency

Selenium deficiency poses danger to heart failure patients.11

A study in the European Journal of Heart Failure found that selenium deficiency in patients with heart failure was associated with lower exercise tolerance and a 50% higher mortality rate. Low selenium was also linked to impaired mitochondrial function in cell cultures of human heart muscle cells.

Selenium deficiency is associated with dangerously low blood sugar.12

A study of healthy adults found that serum selenium concentrations were strongly associated with glucose levels in people who were deficient in selenium.

Hypoglycemia (serum glucose <50 mg/dL) was observed in19.2% of individuals deficient in selenium, but in just 1.4% of those with sufficient levels. This suggests that adequate selenium is important for maintaining healthy glucose levels.

Selenium deficiency induces inflammation in the brain.13 In a study of healthy pigs, a selenium-deficient diet activated a pathway that induced inflammation, which led to pathologic lesions in the brain.

Guard Against Selenium Deficiency

Selenium levels are suboptimal in many people in the industrialized world.14

While the mineral is found in foods such as Brazil nuts and pinto beans, the amount of selenium that can be obtained from diet is highly uneven. That’s because the amount of natural selenium in the soil fluctuates from region to region.

Many areas of the U.S. have selenium-deficient soil.15

Consider using multiple forms of selenium—including Se-Methyl L-Selenocysteine, L-selenomethionine, and sodium selenite—to obtain comprehensive protection.

If you have any questions on the scientific content of this article, please call a Life Extension Wellness Specialist at 1-866-864-3027.


  1. Xu JW, Shi XM, Yin ZX, et al. [Investigation and analysis of plasma trace elements of oldest elderly in longevity areas in China]. Zhonghua Yu Fang Yi Xue Za Zhi. 2010 Feb;44(2):119-22.
  2. Available at: Accessed September 19, 2022.
  3. Yildiz A, Kaya Y, Tanriverdi O. Effect of the Interaction Between Selenium and Zinc on DNA Repair in Association With Cancer Prevention. J Cancer Prev. 2019 Sep;24(3):146-54.
  4. Bera S, De Rosa V, Rachidi W, et al. Does a role for selenium in DNA damage repair explain apparent controversies in its use in chemoprevention? Mutagenesis. 2013 Mar;28(2):127-34.
  5. Zwolak I, Zaporowska H. Selenium interactions and toxicity: a review. Selenium interactions and toxicity. Cell Biol Toxicol. 2012 Feb;28(1):31-46.
  6. Kohrle J. Selenium and the thyroid. Curr Opin Endocrinol Diabetes Obes. 2015 Oct;22(5):392-401.
  7. Broome CS, McArdle F, Kyle JA, et al. An increase in selenium intake improves immune function and poliovirus handling in adults with marginal selenium status. Am J Clin Nutr. 2004 Jul;80(1):154-62.
  8. McCann JC, Ames BN. Adaptive dysfunction of selenoproteins from the perspective of the triage theory: why modest selenium deficiency may increase risk of diseases of aging. FASEB J. 2011 Jun;25(6):1793-814.
  9. Jenkins DJA, Kitts D, Giovannucci EL, et al. Selenium, antioxidants, cardiovascular disease, and all-cause mortality: a systematic review and meta-analysis of randomized controlled trials. Am J Clin Nutr. 2020 Dec 10;112(6):1642-52.
  10. Handa E, Puspitasari IM, Abdulah R, et al. Recent advances in clinical studies of selenium supplementation in radiotherapy. J Trace Elem Med Biol. 2020 Dec;62:126653.
  11. Bomer N, Grote Beverborg N, Hoes MF, et al. Selenium and outcome in heart failure. Eur J Heart Fail. 2020 Aug;22(8):1415-23.
  12. Wang Y, Rijntjes E, Wu Q, et al. Selenium deficiency is linearly associated with hypoglycemia in healthy adults. Redox Biol. 2020 Oct;37:101709.
  13. Zhang Y, Cui J, Lu Y, et al. Selenium Deficiency Induces Inflammation via the iNOS/NF-kappaB Pathway in the Brain of Pigs. Biol Trace Elem Res. 2020 Jul;196(1): 103-9.
  14. Hughes DJ, Fedirko V, Jenab M, et al. Selenium status is associated with colorectal cancer risk in the European prospective investigation of cancer and nutrition cohort. Int J Cancer. 2015 Mar 1;136(5):1149-61.
  15. Available at: Accessed September 21, 2022.