Higher selenium intake reduces the risk of chronic diseases and early death

Selenium deficiency is widespread in Europe and many other parts of the world, negatively impacting public health. On the other hand, adequate selenium intake through diet and supplements can reduce the risk of cardiovascular diseases, diabetes, metabolic disorders, cancer, and early death. A study published in Frontiers in Nutrition suggests that older individuals have an increased need for selenium.

Selenium is an essential trace element involved in a range of selenium-dependent proteins and enzymes that are important for energy metabolism, immune function, fertility, thyroid health, and cancer prevention. Additionally, selenium is part of unique antioxidants that protect against atherosclerosis and cellular damage caused by free radicals and oxidative stress. According to the WHO, selenium intake is too low in Europe, large parts of China, Africa, and India. It is also too low in certain areas of the USA.
In the new study, researchers gathered data from a large American population study called the National Health and Nutrition Examination Survey (NHANES), which has monitored the nutrition and health status of the population for decades using questionnaires, blood tests, and more. Using another index (National Death Index), the researchers obtained data on participants who had passed away in the meantime.
The study analyzed 25,801 individuals, divided into five groups (quintiles) based on how much selenium they consumed from their diet and supplements between 2007 and 2018. The researchers adjusted for confounding factors such as age, gender, smoking, alcohol consumption, and BMI. During the study, 2,436 participants died.
The results revealed that a moderate or higher intake of selenium (≥ 129 micrograms/day) is associated with a lower risk of cardiovascular disease. Additionally, an adequate selenium intake can protect against early death from cardiovascular disease and other causes. The study also suggests that the need for selenium increases after the age of 50, making high-dosed supplements potentially relevant. This is partly due to the fact that the aging process is marked by oxidative stress and chronic low-grade inflammation, which selenium is able to counteract by supporting normal immune function and acting as a potent antioxidant.

The real selenium need versus official recommendations

The new study shows that the optimal daily selenium intake should ideally be above 129 micrograms. It can be added that this amount is significantly higher than the Danish Veterinary and Food Administration’s recommendation of 55 micrograms and somewhat higher than the new Nordic Nutrient Recommendations (NNA), where women and men should consume 75 and 90 micrograms daily, respectively. In many studies, 200 micrograms daily have been given to optimize blood levels, which should ideally be around 125 micrograms per liter. On the other hand, one should not consume too much selenium, as the European Food Safety Authority (EFSA) states that the upper safe limit for daily selenium intake is 300 micrograms.
Regarding supplements, it may be advantageous to choose pharmaceutical-grade selenium yeast, which has higher bioavailability and better therapeutic effects.

• Selenium is found in the soil and absorbed by plants.
• Grains, meat, organ meats, eggs, dairy products, and nuts are the richest sources of selenium.
• The selenium content in the soil can vary by over a thousand percent depending on local soil conditions, which is reflected throughout the food chain.
• Furthermore, intensive farming methods degrade selenium content.
• Selenium is also found in fish and seafood, but it is difficult to meet the actual need through these sources.
• Vegetarians, vegans, and older individuals are at an even greater risk of selenium deficiency.
• It is estimated that over one billion people worldwide lack selenium.
• This contributes to infections, chronic diseases, and early death.

References:

Yuchen Zhang et al. Association of dietary selenium intake with the risk of chronic diseases and mortality in US Adults. Frontiers in Nutrition 2024

Puze Wang et al. Selenium intake and multiple health-related outcomes: an umbrella review of meta-analysis. Frontiers in Nutrition. 2023

Yin Sun. Review on the health-promoting effect of adequate selenium status. Frontiers in Nutrition. 2023