Aging slowed and longevity promoted by selenium

Can optimal selenium status influence aging and longevity?

Dr. Jan Alexander, MD, Ph.D., is the co-author of the selenium scoping article [Alexander and Olsen 2023] for the 2023 Nordic Nutrition Recommendations and is a co-author of several KiSel-10 sub-studies.

A 2026 review suggests that maintaining an appropriate selenium status may be important for healthy aging. However, it does not conclusively show that selenium supplementation prolongs human life. We need more clinical evidence, especially from studies of selenium supplementation of individuals with low selenium status [Pierce & Mackrill 2026].

Instead, the review emphasizes mechanistic and observational evidence to explain how optimal selenium intake and selenium status may be important. At the same time, the authors point out that both selenium deficiency and selenium excess can be detrimental. There seems to be a U-shaped relationship between selenium status and good health and longevity [Pierce & Mackrill 2026].

What constitutes optimal selenium status?

In a 2024 study, Larsen et al estimated that serum selenium status of about 120–130 mcg/L is optimal. That range is the serum concentration associated with maximizing circulating selenoprotein P (SELENOP). Larsen et al regarded SELENOP as the most informative marker of selenium status because SELENOP is the primary selenoprotein for selenium transport and supply to tissues [Larsen 2024].

Larsen et al indicated that an intake of approximately 100 mcg selenium/day will be sufficient to achieve and maintain a serum concentration of 120 mcg/L in a selenium-deficient population. Their estimate of 100 mcg/day refers to total selenium intake [Larsen 2024].

Interestingly, the 2023 Nordic Nutrition Recommendations review described the same rationale: SELENOP reaches its plateau in the blood at a higher selenium concentration than glutathione peroxide-3 (GPx3) Therefore, maximizing SELENOP is the criterion for an adequate selenium status [Alexander & Olsen 2023].

The NNR review notes that ca. 100 mcg/L should come close to maximizing the blood SELENOP concentration. However, the authors Alexander & Olsen say that the health implications of maximizing SELENOP remain unclear [Alexander & Olsen 2023].

What constitutes selenium deficiency?

In the 2024 Newcastle 85+ study by Perri et al, the researchers identified serum selenium status less than 70 mcg/L as suboptimal status and less than 45 mcg/L as deficient status [Perri 2024].

How much selenium intake is too much?

The central argument in the Pierce and Mackrill review is that selenium has a narrow beneficial range. Both insufficient and excessive selenium status can adversely affect health and longevity.

In 2023, EFSA established 255 mcg selenium/day as the Tolerable Upper Intake Level (UL). This refers to the total daily selenium intake from all sources: food, supplements, fortified foods, etc. The limit of 255 mcg/day is not the level at which toxicity suddenly begins. Rather, EFSA considers it to be the highest chronic daily intake that is not expected to pose a risk of adverse effects for most people [EFSA 2023].

What biological activity connects selenium to healthy aging?

Selenium’s biological activity occurs primarily through the action of selenoproteins: glutathione peroxidases, thioredoxin reductases, iodothyronine deiodinases, SELENOP, and several more selenoproteins. These selenoproteins participate in redox regulation, protection against oxidative damage, calcium handling, cellular stress responses, metabolism, and regulation of cell survival and death. Pierce & Mackrill connect these functions with several fundamental processes of aging.

Selenium does not act through a single anti-aging mechanism. It acts as a network of processes that can support or impair healthy aging depending on selenium availability and biological circumstances.
Pierce & Mackrill distinguish between health span and lifespan. Selenium deficiency correlates to impaired health and increased vulnerability to conditions including immune dysfunction, cognitive decline, skeletal-muscle disorders, metabolic disease, and certain cancers.
Another consideration is that the availability and function of copper, zinc, folate, resveratrol, vitamin A, α-linolenic acid, and Coenzyme Q10 as well as physiological factors such as exercise and caloric restriction affect the action of selenium as a potential anti-aging agent.

What is the take home message from the KiSel-10 study?

Professor Urban Alehagen’s Swedish KiSel-10 studies showed that, in older adults with relatively low selenium status, four years of combined selenium (200 mcg/day) and Coenzyme Q10 (200 mg/day) supplementation was associated with improved cardiac function and substantially lower cardiovascular mortality, with the mortality difference persisting during 10–12 years of follow-up [Alehagen 2018].

Conclusion: Selenium and Aging and Longevity

Pierce and Mackrill show why selenium can be beneficial at appropriate levels but harmful when deficient or excessive.

The authors show why individual selenoproteins may have distinct effects on aging.

The review suggests that maintaining an optimal selenium status may be important for healthy aging.

Sources

Alehagen U, Aaseth J, Alexander J, Johansson P. Still reduced cardiovascular mortality 12 years after supplementation with selenium and coenzyme Q10 for four years: A validation of previous 10-year follow-up results of a prospective randomized double-blind placebo-controlled trial in elderly. PLoS One. 2018 Apr 11;13(4):e0193120.

Alexander J, Olsen AK. Selenium – a scoping review for the Nordic Nutrition Recommendations 2023. Food Nutr Res. 2023 Dec 28;67.

EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA). Scientific opinion on the tolerable upper intake level for selenium. EFSA J. 2023 Jan 20;21(1):e07704.

Larsen C, Winther KH, Cramon PK, Rasmussen ÅK, Feldt-Rasmusssen U, Knudsen NJ, Bjorner JB, Schomburg L, Demircan K, Chillon TS, Gram J, Hansen SG, Brandt F, Nygaard B, Watt T, Hegedus L, Bonnema SJ. Selenium supplementation and placebo are equally effective in improving quality of life in patients with hypothyroidism. Eur Thyroid J. 2024 Feb 5;13(1):e230175.

Perri G, Mathers JC, Martin-Ruiz C, Parker C, Walsh JS, Eastell R, Demircan K, Chillon TS, Schomburg L, Robinson L, Hill TR. Selenium status and its determinants in very old adults: insights from the Newcastle 85+ Study. Br J Nutr. 2024 Mar 14;131(5):901-910.

Pierce WG, Mackrill JJ. Selenium in aging and longevity. Biochimie. 2026 Sep 8:S0300-9084(26)00221-X. doi: 10.1016/j.biochi.2026.09.002. Epub ahead of print.

The information presented in this review article is not medical advice. The reader should not use this information as medical advice.

Milestones in early selenium research

1817 Swedish chemist Jöns Jakob Berzelius discovers selenium

1957 Biochemist Klaus Schwarz shows that selenium in microscopic amounts has a vital importance for mammalian health

1969 Professor J.T. Rotruck discovers that selenium has a biochemical role as a component of the antioxidant enzyme glutathione peroxidase

1969 Professors R.J. Shamberger and D.V. Frost report a possible protective effect of selenium against cancer in humans

1973 Professor J.T. Rotruck identifies the enzyme glutathione peroxidase as a selenium-dependent protein

1977 Professor G.N. Schrauzer publishes cancer mortality correlation studies showing an inverse correlation between dietary intakes of selenium and cancer mortality in 27 countries

1988 Professor G.Q Yang summarizes the lessons learned about the selenium-related endemic diseases Keshan disease and Kashin-Beck disease and about the importance of adequate daily selenium intakes

1989 Professor G.G. Duthie publishes evidence for a role of selenium in the prevention of cardiovascular disease

1993 Researcher W.J. Blot publishes the results of the Nutrition Intervention Trials in Linxian, China, showing that supplementation with a combination of selenium and other antioxidants reduces the risk of cancer

1994 Professor G.N. Schrauzer publishes evidence that selenium is important in the maintenance and therapy of HIV-infected patients

1996 Professor Larry Clark publishes the results of a randomized controlled trial – the Nutritional Prevention of Cancer study -- that shows selenium's cancer-protective effects on colon cancer, lung cancer, and prostate cancer

1997 Professor G.F. Combs summarizes the evidence for the protective effects of selenium against cancer

1999 Professor J.E. Oldfield publishes his Selenium World Atlas, mapping areas of selenium deficiency around the world

2000 Researcher O.A. Levander publishes evidence showing an anti-viral effect of selenium

2002 Researcher R. Gärtner shows that supplementation with selenium reduces inflammation in patients with autoimmune thyroiditis

2002 Researcher Margaret Rayman presents the arguments for increasing selenium intakes to realize selenium’s antioxidant and anti-viral and anti-inflammatory effects as well as selenium’s enhancement of immune function and reproductive success.