According to a recent study, published Online First in The Lancet , selenium may help people who don’t have enough of it, but for the people who have enough to begin with, selenium supplements may be detrimental to their health. It is shown in the study that taking the supplements may result in the development of type 2 diabetes.
Margaret Rayman, from the University of Surrey, Guilford, UK, and author of the study explains:
“The intake of selenium varies hugely worldwide. Intakes are high in Venezuela, Canada, the USA, and Japan, but lower in Europe. Selenium-containing supplements add to these intakes, especially in the USA where 50% of the population takes dietary supplements.”
The study states that selenium is a consistent, natural mineral which is present in certain foods and also in soil. High selenium intake has previously been shown to protect against certain cancers, such as lung, colorectal, bladder, and prostate cancer. It has also been known to increase male fertility and have positive effects on antiviral function.
Low selenium intake has been linked to memory and brain decline, low immune system quality, and a greater risk of death. However, studies have shown that selenium has a low therapeutic spectrum and when consumed too much may result in the development of type 2 diabetes.
The authors state that worldwide, people are taking selenium supplements much more than before, because they think it lowers their chances of developing cancer and other deadly conditions, and the supplements have been sold in large quantities with the belief that they help many health problems.
Researchers state that evidence from studies had differed greatly in whether or not selenium supplements are beneficial to health. Rayman says that the mix in results is due to the fact that selenium is only helpful when the levels in people taking the supplements are low. She says that the most beneficial factor of the supplements is associated to people who have inadequate selenium blood levels.
Rayman adds:
“The crucial factor that needs to be emphasized is that people whose blood plasma selenium is already 122 µg/L or higher – a large proportion of the US population (the average level in American men is 134 µg/L) – should not take selenium supplements. However, there are various health benefits, and no extra risk, for people of lower selenium status (plasma level less than 122 µg/L), who could benefit from raising their status to 130 – 150 µg/L – a level associated with low mortality.”
Written By Christine Kearney