First, a quick biology lesson: The liver is responsible for binding hormones by converting them into their “methylated” forms (i.e., by converting them from fat-soluble to water-soluble). Once this happens, the bound hormones are then transported into the gut, where they can be safely excreted, explains Wendie Trubow, M.D., functional medicine gynecologist.
But what happens when that excretion is delayed because you’re constipated? “If your bowels aren’t moving, your estrogen sticks around longer than it should and goes back into circulation in the body,” says Jolene Brighten, NMD, women’s hormone expert and author of Beyond the Pill. “You have to poop every day to get your estrogen out.”
Additionally imbalances in gut flora can lead to increased production of beta-glucuronidase—an enzyme that essentially reactivates bound estrogen and other hormones by disconnecting them from their methyl group. When this happens, estrogen, which is no longer water-soluble, gets reabsorbed into the bloodstream. “Constipation exacerbates this process since the hormone is sitting in the stool for longer and has a greater chance of being separated from the methyl group,” says Trubow.