The absorption of dietary and supplemental selenium has an important and positive influence on human longevity. Selenium researchers have called selenium a “longevity element.” The selenoenzymes and selenoproteins of which selenium is an essential component have antioxidant, anti-inflammatory, and anti-cancer activity in humans [Li 2024].
Maintaining selenium absorption and metabolism at an optimal physiological state seems to be one of the primary factors for good health and longevity of the elderly people. In particular, scientific studies have shown that selenium intake and status play an important role in the incidence and progression of some chronic diseases [Li 2024]:
- Cancer: inducing tumor cell apoptosis, reducing the mutagenicity of carcinogenic factors, prolonging the cell division interval, and slowing proliferation of malignant cells
- Heart failure: improving exercise tolerance, reducing mortality rate, and improving quality of life
- Heavy metals: binding to mercury, sequestering mercury, reducing mercury’s biological availability and reducing the damage to the kidney caused by exposure to heavy metals
- Antioxidant effects: restoring the antioxidant defense system of the body
Selenium-Rich Soil in a Chinese Longevity Township
Bama Yao Autonomous County is the only longevity township in China that is globally recognized as having a continuously growing longevity population. In 2020, Bama had 102 residents over 100 years old. The number had increased from the 2000 census (74 residents over 100 years of age) and the 2010 census (82 residents over 100 years of age). Bama has relatively stable genetic and geographic factors and a relatively stable dietary culture [Li 2024]. The proportion of centenarians is nearly six times greater than the international standard proportion [Zhang 2023].
People living in Bama consume locally produced natural food crops and fruits and have a dietary fiber–polysaccharide diet based on porridge, mixed grains, vegetables, and the meat of domestic animals. The local diet is characterized by high dietary fiber, high vitamin content, and low calorie content.
Epidemiological studies show that elderly people in Bama tend to be quick-witted and in good mental health. Relatively few of them have cancer, cardiovascular, or cerebrovascular disease. Most Bama residents die of old age, rather than from a specific illness [Li 2024].
Accordingly, Chinese researchers undertook an examination of the possible effect of selenium intake and status on the longevity of the residents of Bama Township [Li 2024].
Generally speaking, the soil in China is selenium-deficient. Bama Township, on the other hand, is in a selenium-rich area of China. The average selenium concentration in the soil in Bama Township is 0.62 mg/kg (range: 0.14–10.5 mg/kg), which is significantly higher than the selenium content of most topsoil in China and in countries such as Japan and Sweden [Li 2024].
Selenium Intake and Selenium Status in a Chinese Longevity Township
Se is an essential element. The selenium content in crops and fruits is closely related to the selenium concentration in the soil. Poor selenium deposits in the soil and selenium deficiency can result in cause human health problems.
We humans cannot synthesize selenium. Selenium must be ingested and absorbed to meet our nutritional needs. In Bama Township, the average selenium intake is reported to be 83 micrograms per day [Li 2024]. This is a higher intake than the recommended selenium intake for the elderly over the age of in China: 60 micrograms per day. It is a safe daily intake, as it is considerably below the tolerable upper limit of 255 micrograms per day established by EFSA [2021] and by the Nordic Nutrition Recommendations [Blomhoff 2023].
Thus, the average selenium intake in Bama Township is considerably higher than the estimated average selenium intake in Denmark, Germany, Spain, Sweden, Switzerland, The Netherlands [Li 2024].
The Chinese researchers regard selenium concentration in the hair as the most appropriate measurement for assessing long-term selenium status. In Bama Township, the concentration in the hair of elderly citizens ranged between 0.15 and 0.75 micrograms of selenium per gram of hair. The mean concentration was 0.41 micrograms of selenium per gram of hair [Li 2024].
In men, the selenium concentrations in the hair were higher than the selenium concentrations in women. The researchers suggested that men eat more selenium-rich foods than women do, e.g., more meat.
The elderly subjects with the highest levels of selenium in their hair were mostly between 76–80 years old. Above 80 years of age, the human body seems to lose the ability to absorb and metabolize selenium. Above 80 years, both selenium intake and selenium metabolism decrease. However, the rate of selenium metabolism is higher than the rate of selenium intake, resulting in an overall loss of selenium. Consequently, the Chinese researchers recommend selenium supplementation for people over the age of 80 years to maintain physiological balance [Li 2024].
Conclusion: Selenium as a Longevity Element
For a beneficial anti-aging effect, sufficient selenium intake and accumulation in the body is necessary.
Adequate selenium intake can delay aging in the following ways [Li 2024]:
- ensures the timely neutralization of harmful free radicals and prevents oxidative damage
- improves the anti-inflammatory and immune functions of the body
- reduces the risk of cancer, heart disease, liver disease, and renal disease
- maintains the glomerular filtration rate at a normal level and prevents renal disease in the elderly
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The information presented in this review article is not intended as medical advice and should not be used as such.
15 March 2024