Functional Nutrition for Estrogen Dominance

What is estrogen dominance?

Estrogen dominance occurs when estrogen levels are elevated relative to progesterone.

The specific term “estrogen dominance” is popular online, but it is not technically a medical diagnosis. More commonly, healthcare practitioners will call it “estrogen excess with low progesterone.”

What are some conditions associated with estrogen dominance?

The following may occur in people with estrogen dominance:

  • Irregular menstrual bleeding (1)
  • PMS (2)
  • Anxiety (3)
  • Increased risk of hormone-sensitive cancers (like breast, uterine, ovarian, and prostate) (4)
  • Some autoimmune diseases, including lupus and Hashimoto’s (567)
  • Vagnial infections (8)
  • Uterine fibroids (9)
  • Fibrocystic breasts (10)

What can trigger estrogen dominance?

The following have been linked to estrogen dominance:

  • Excessive estrogen production
  • No ovulation (because then progesterone isn’t produced to balance out the estrogen) (11)
  • Poor estrogen metabolism
  • Excess body fat (because estrogen can be made in fat cells) (12)
  • High levels of cortisol (13)
  • High insulin levels (11)
  • Environmental factors, like exposure to estrogen-mimicking chemicals (14)

What are some ways to lower estrogen levels and improve estrogen metabolism?

The following diet and lifestyle interventions may help lower estrogen levels:

1. Reduce exposure to estrogen-mimicking chemicals

A variety of chemicals can be classified as “endocrine disruptors” that mess up natural hormonal balance and function.

Some of these chemicals are particularly disruptive to the estrogen system and can mimic or interfere with the actions of estrogen within the body (14).

Some of these chemicals include polychlorinated biphenyls (PCBs), bisphenol A (BPA), and phthalates (15).

PCBs have been banned from production since 1977, but people can still be exposed to them from items that were produced before then.

Examples include old electrical equipment or old fluorescent lighting that has begun to leak.

PCBs also bio-accumulate in the food chain, so some animals, as well as large fish and bottom-feeding fish like carp, can contain PCBs (although thankfully levels have been declining since their ban).

BPA is used to create polycarbonate (a hard clear plastic) and is also used in resins.

Exposure can be reduced by replacing plastic items with glass whenever possible and reducing your intake of canned foods (even BPA-free cans can contain other endocrine-disrupting chemicals).

If you do use plastic, try not to heat it up (in the microwave, with hot foods or water, etc.) since that can increase BPA leaching.

Phthalates can be found in many plastics and even personal care products. You can reduce your exposure with the same tips for avoiding BPA and by using natural personal care products.

2. Consume fiber and lignan-rich foods (flax, leafy greens, bran, etc.)

In general, high-fiber and lignan-rich diets have been linked to lower estradiol levels and better estrogen metabolism (16).

There are a few reasons why this might be:

Lignans (a type of polyphenol found in plants) have been shown to inhibit aromatase activity, the enzyme that produces estrogen in the peripheral tissues. Reducing aromatase activity is a good thing for estrogen dominance (17).

Fiber helps reduce the activity of beta-glucuronidase, an enzyme produced by gut bacteria that breaks down estrogen metabolites so they are more likely to be absorbed back into circulation (which is not what you want with estrogen dominance) (18).

Flax can increase SHBG, which binds to estrogen so it is not available to act on tissues. It also inhibits aromatase and increases the metabolism of estrogen down the beneficial 2-OH pathway (19).

3. Maintain healthy body fat levels

Fat cells (adipocytes) make aromatase, the enzyme that converts testosterone to estrogen. Having a large number of fat cells may increase estrogen beyond desirable levels (20).

Maintaining a healthy body fat percentage of roughly 25 to 35% (depending on age) may help prevent excessive estrogen production within fat cells.

4. Improve insulin sensitivity

High insulin levels may increase aromatase activity, triggering the production of more estrogen (although more high-quality research is needed to demonstrate this definitively) (2122).

Elevated insulin also reduces the production of SHBG by the liver, increasing the potency of the estrogen that is circulating (23).

This may at least partially explain the link between type 2 diabetes, obesity, and breast cancer (24).

Improving insulin sensitivity with diet and exercise is recommended (25).

5. Consume omega-3 fats

An interesting body of research suggests that consuming omega-3 fatty acids, especially EPA, can improve estrogen metabolism.

One study found that supplementing with omega-3s increased the (good) 2-OH pathway of estrogen metabolism, and decreased the harmful 16-OH pathway in humans (26). However, another study on DHA did not find any benefit, so more research is needed in order to make specific recommendations (27).

Since inflammation has also been linked to estrogen dominance, the anti-inflammatory benefits of EPA/DHA may be helpful as well.

6. Consume weak phytoestrogens

Some plant foods, like soy, contain lignans and isoflavones that act as phytoestrogens (plant-based compounds that are similar to estrogens).

These phytoestrogens can bind to estrogen receptors but are far less powerful than actual estrogen. This may help block the negative effects of excess estrogen by preventing actual estrogen from attaching to estrogen receptors.

Phytoestrogens also increase SHBG, decrease aromatase, and promote the 2-OH vs the 16-OH metabolism pathways (2829).

Other foods that are good sources of phytoestrogens include flax, sesame, sunflower seeds, legumes, whole grains, and alfalfa and clover sprouts (3031).

Consuming 2 tablespoons of ground flax every day for 7 weeks has been shown to increase 2-OH metabolites in postmenopausal women and improve the ratio of 2-OH to 16-OH estrogen metabolites (32).

Interestingly, new research has found that having healthy gut bacteria may also play an important role in transforming phytoestrogens into the most beneficial and health-promoting metabolites (33, 34).

7. Reduce aromatase activity

Since aromatase is responsible for converting testosterone to estrogen, consuming foods and substances that reduce the activity of aromatase may be helpful for estrogen dominance.

Some of these compounds (like lignans) have been discussed above, but additional supplements that may be helpful include melatonin, green tea, ginkgo biloba extract, and citrus flavones (353637383940).

Reducing inflammation and improving insulin sensitivity may help as well.

8. Eat cruciferous vegetables and/or take DIM 

Cruciferous vegetables (broccoli, cauliflower, brussels sprouts, cabbage, etc.) naturally contain compounds called glucosinolates that are metabolized into compounds that have beneficial effects on estrogen metabolism.

Lots of research has found that cruciferous vegetables promote the metabolism of estrogen down the good 2-OH pathway and away from the harmful 16-OH pathway (41).

However, since large amounts of vegetables (like 500 grams or 1.1 lbs of broccoli) are needed per day to shift metabolism, many people choose to take supplements instead.

DIM (diindolylmethane) is the preferred supplement by many since it is the active metabolite that benefits estrogen metabolism.

One study found that 108 mg of DIM per day for 30 days can increase 2-OH metabolites excreted in the urine (42).

9. Adequate B-vitamins

Vitamin B6, vitamin B12, and folate all support the 2-OH pathway of estrogen metabolism.

This is because this pathway requires a well-functioning methylation system in order to properly process and excrete the estrogen metabolites.

Interestingly, vitamin B6 may also decrease the downstream genetic effects of stimulated estrogen receptors, reducing the strength of estrogen’s effects (43).

10. Magnesium, SAMe, and Glutathione

Magnesium and SAMe are required for optimal functioning of the COMT enzyme involved in the 4-OH pathway of estrogen metabolism.

If magnesium or SAMe are deficient and COMT cannot function properly, it may lead to increased production of cancer-promoting quinones within the estrogen metabolism pathway.

Once quinones are formed, glutathione is required to neutralize them back into harmless compounds.

11. Promote bowel movements

Since a portion of the estrogen metabolites formed in the liver is secreted back into the gut via bile, these metabolites can be reabsorbed back into the bloodstream.

Gut bacteria and bowel patterns play a role in this, but in general, constipation causes the stool to remain in the colon longer and can increase the reabsorption of things like estrogen metabolites (44).

To stimulate regular bowel movements, encourage fiber consumption, proper hydration, and possibly magnesium supplementation. For more suggestions, see the note on constipation.

12. Drink less alcohol

Heavy alcohol consumption raises estrogen levels, which is not what we want in cases of estrogen dominance (45)!

Abstaining or drinking in moderation may be beneficial for people with estrogen dominance.

One study in postmenopausal women found that 1 glass of wine per day for 8 weeks did not affect estrogen metabolites, but 2 glasses per day shifted estrogen metabolism towards the harmful 16-OH pathway (46).

13. Decrease inflammation

New research has found that inflammation can also increase aromatase activity and lead to the production of more estrogen within fat cells (47).

In fact, this may be an even bigger influence on estrogen levels than BMI or body fat levels alone (48).

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