A new study has found that premenopausal women with depression have 43% lower levels of oestradiol, a form of oestrogen related to positive mood, than women without the condition. The study, conducted by researchers at the Renmin Hospital of Wuhan University in China, suggests that a species of gut bacteria known as Klebsiella aerogenes may contribute to this difference.
The researchers found that gut bacteria from women with depression quickly broke down oestradiol into other substances more quickly than bacteria from women without the condition. Additionally, when female mice were fed K. aerogenes, they had lower oestradiol levels and exhibited more depressive symptoms than mice not given the bacterium.
The findings suggest that K. aerogenes may lower oestradiol levels, which in turn could contribute to depression in women. Timothy Sampson of Emory University in Atlanta, Georgia, noted that further research is needed to determine the significance of this effect and to develop new drugs targeting specific microbes and their metabolic processes.