This question recently prompted French researchers to conduct a study of almost 1400 subjects aged between 60 and 71, only to find low intake of selenium may contribute to a decrease in cognitive function.
With results published in a recent edition of Epidemiology, researchers compared changes in cognitive function and selenium levels. They reported that over nine years of follow up, brain function decline was associated with decreases in plasma selenium.
As lead author N. Tasnime Akbaraly from the University of Montpellier explains, "Because brain oxidative stress is a cause of cognitive impairment, selenium, which is an antioxidant, may protect against cognitive decline." The mineral selenium has also been found to boost the immune system.
Akbaraly states that further research is needed to confirm the link between decreased cognitive function and selenium levels, the results of which could "shed new light on the potential benefits of supplementation".
Falling levels of selenium have caused concern in Europe since the EU imposed measures causing a drop in wheat imports from the US, where soil selenium levels remain high. While the European recommended daily intake is 65mcg (micrograms). intakes the UK average just 34 mcg.
References available on request