Young people can be at greater risk of depression if their bodies have too much or too little of the trace element selenium, according to New Zealand research out Thursday.
A total of 978 young adults aged 17 to 25 were asked to complete a depression questionnaire and track their mood daily for two weeks, while blood tests were also taken to determine their selenium levels in the University of Otago study.
Young adults with either too low or too high levels of selenium showed the highest risk of depressive symptoms and poorer mood, but lower concentrations were found to be more detrimental, study leader Dr Tamlin Conner said in a statement.
"Our strongest finding was that young adults with the lowest selenium concentrations reported the most depressive symptoms," said Conner.
Adequate selenium intake was required to prevent oxidative damage to the brain and nervous system, which contributed to the development of depression.
"New Zealand has a well-known history of low selenium intake, with many people having intakes below what is required for maximum antioxidant defenses," said Conner.
However, clinical trials would be necessary to determine whether increasing selenium intakes in young people with low intake could reduce the risk of depression.
Co-author Dr Jody Miller said some studies showed associations between very high selenium intakes and increased risk of diabetes, prostate cancer and mortality usually in older adults so supplements were not recommended.
"Safe ways to ensure a good selenium intake without the risk of consuming too much include choosing breads made with whole grains, and increasing the consumption of other high selenium foods such as canned fish, nuts and seeds, poultry and eggs," Miller said in the statement.