Everything we breathe, ingest, or absorb through the skin gets into the bloodstream and eventually passes through the liver. Because the liver is the body’s primary detoxifier, keeping it healthy is critical to your overall health, including proper metabolism and function of your hormones.
As unglamorous as it sounds, the liver operates somewhat like a sewage treatment plant. The liver takes everything we put into our bodies—whether it is swallowed, inhaled, or absorbed through the skin—and filters it. The liver’s filtration process separates the nutrients that the body needs for energy and all of its other functions and prepares to dispose of that which the body does not need, such as metabolic waste, toxins, and excess substances. Specific liver functions include:
- Converting fats, proteins, and carbohydrates to energy and nutrients
- Creating bile to break down fats and eliminate fat-soluble toxins and excess substances, including excess hormones
- Removing harmful chemicals, bacteria, and excesses
- Metabolizing drugs and breaking down alcohol
- Storing vitamins and minerals, such as iron
- Storing sugars as fuel (glycogen) for future use
- Helping to maintain fluid and electrolyte balance
- Creating serum proteins that act as hormone carriers
- Creating immune substances, such as gamma globulin
- Filtering blood, regulating blood clotting, and storing extra blood for quick release
- Manufacturing testosterone and the estrogen hormones
- Regulating sex hormone levels and eliminating excess hormones
Health problems can arise when we put things into our body, both consciously and unconsciously, that are toxic or build up an excess or toxicity over time, such as:
- Oily, processed foods
- Man-made chemicals including preservatives, pesticides, and lead from paints or gasoline
- Alcohol and drugs (therapeutic or otherwise)
- Excess hormones
Health problems can also occur if the nutrients that the liver needs to process toxins or excesses are in limited supply. Like a sewage treatment plant that is short-staffed, if these nutrients are in short supply, the liver cannot process as quickly or as thoroughly as needed. If the liver becomes overburdened because of insufficient nutrients, the toxins or waste build-up and the excess can escape back into the body, leading to serious health concerns.
The liver plays a vital role in the body’s use of hormones, both those that are produced naturally in our bodies as well as those hormones that are “introduced” via hormone therapies. It acts as a hormone processor, manufacturing and/or regulating some hormone levels and directing various hormones to perform their proper function in other parts of the body. But when the body experiences a hormone excess (whether produced by the body or introduced by hormone therapy), the liver may not be able to process the hormone(s) as quickly or efficiently, causing a hormone imbalance.
Of primary concern for women’s health is the liver’s role in regulating the sex hormones, primarily the estrogen hormones. This is a consideration for women undergoing hormone therapy, whether it is conventional hormone replacement therapy (HRT), typically consisting of synthetic hormones that are not biologically identical to human hormones, or biologically-identical hormone therapy (BHT).
Researchers are gaining new insight into how estrogens are metabolized and the effects of that metabolism. They found that estrogens break down into estrogen metabolites that have varying levels of estrogenic activity, and that the stronger the estrogenic effect, the greater the risk of developing estrogen-related cancer.
Phase I and Phase II Pathways
The liver metabolizes hormones and other substances using two primary phases known as the Phase I and Phase II pathways. During Phase I, some hormones or substances are metabolized directly, but often they are converted into intermediate forms, which are then further metabolized in Phase II. Cumulatively, these two phases of biological transformation are how the liver provides the body with nutrients and supports the excretion of excess or toxic substances in the urine, liver bile, perspiration, and exhaled air.
The pathways depend on a large number of nutrients, including enzymes and amino acids, and their availability (or lack thereof) seems to have a significant influence on the metabolic outcome. For example, the Phase I pathway is the main metabolic pathway for the estrogen hormones. In premenopausal women, the ovaries produce estrogen, primarily estradiol, most of which the body converts to estrone, and eventually estriol. The liver then metabolizes the remaining estradiol and the converted estrone, breaking it down further, and excreting the excess from the body.
Some researchers and practitioners now believe that the liver’s ability to metabolize estrone is the key to understanding estrogen-related cancer risk. During Phase I metabolism, estrone is converted into various metabolites including 2-hydroxyestrone, a very weak estrogen, and 16-alphahydroxyestrone, a very potent estrogen. If the conversion process favors the stronger form(s) rather than the weaker form(s), then tissue that has an abundance of estrogen receptors, such as the breasts and uterus, may be more vulnerable to excessive estrogen activity, potentially leading to the formation of fibroids or the stimulation of estrogen-sensitive cancers.
Many factors may affect Phase I processing, including extreme overload, the effects of alcohol or drugs, a lack of nutrients, or interference from other substances. For example, grapefruit juice may slow down the enzymes in Phase I, potentially altering hormone balance. Additionally, many prescription drugs are metabolized in Phase I, which may also interfere with the liver’s ability to handle estrogen hormones. On the other hand, Indole-3-carbinol (I3C), a phytonutrient derived from cruciferous vegetables (e.g., broccoli, cauliflower, cabbage, and Brussels sprouts), stimulates enzymes that promote the metabolism of estrogens into milder forms, potentially reducing the risk of estrogen-dependent cancers.