A new study shows how trace elements including heavy metals can impact cognitive function in older adults, depending on their diets.
Some trace elements are already known to affect cognitive function in older adults, believed to be due to an inflammatory response. Some of the metals occur naturally, but some can act as neurotoxins.
In a report published Monday in BMC Public Health, researchers detailed how they evaluated data from the 2011-2014 National Health and Nutrition Examination Survey (NHANES) survey. The team looked at data from blood samples of 1,726 people aged 60 and older. They used these analyses to explore the relationship between exposure to five trace elements (lead, cadmium, mercury, manganese, and selenium) and cognitive performance. Additionally, researchers compared the effects of these trace elements with the participants’ eating patterns (whether they ate an anti-inflammatory or pro-inflammatory diet).
People with higher selenium exposure performed better on the instant recall test (IRT) and digit symbol substitution test (DSST) tests. IRT measures the acquisition of new linguistic material immediately and after a delay period, while the DSST can gauge other cognitive skills, such as reaction time, sustained attention and working memory.
“This finding aligns with previous research indicating that selenium, an essential trace element with antioxidant properties, may help to mitigate oxidative stress and inflammation in the brain. However, physiological aging may decrease the absorption and utilization of selenium, and thus, the potential risk of selenium deficiency cannot be overlooked in this population,” the authors wrote.
Cadmium, however, was associated with worse DSST results. Lead was linked to poor IRT scores. Both elements are known to cause oxidative stress and neuroinflammation in the body, the researchers pointed out.
The positive effects of selenium and the negative effects of cadmium were both more pronounced among people eating a pro-inflammatory diet.
“These findings suggest that dietary quality may modify the impact of trace element exposures on cognitive health in older adults,” the authors noted.
