Scientists have found an enzyme that can cause depression in women.

Chinese scientists compared the blood serum of 91 women with depression and 98 women without it. It turned out that the first group had almost half the level of estradiol, the main form of estrogen that the body uses in fertile years. Estradiol is formed in the ovaries, and then metabolized in the liver and enters the intestine. From there, it is partially absorbed back into the bloodstream to maintain circulating estrogen levels. The researchers tracked the activity of estradiol in the gut. It was almost completely destroyed by the microbiome of depressed women. Probably, the bacterial strain Klebsiella aerogenes TS2020 is responsible for the degradation of the hormone and the onset of symptoms of the disease. Scientists believe that bacteria that break down estradiol in the gut may be better targets for effective treatment of mental disorders.