What the heck does phytoestrogen even mean, anyways? The term phytoestrogen literally means “plant” (phyto) estrogen. Did you know plants make their own estrogen, too? And interestingly enough, when we ingest plant-sources of estrogen, they have an impact on us as well.
Phytoestrogens have a longstanding history of use in herbal medicine, and with it comes a windy road of how we’ve come to understand these interesting and powerful plant molecules. How do they interact with the human body? What health conditions can they help? Are there any cautions we need to worry about?
Come with me on this journey! We’re about to find out…
Where Can You Find Phytoestrogens?
Before we dive into how they interact in our bodies, let’s talk about where to find them! It may surprise you to find out that you may already be eating plenty of phytoestrogenic foods on a daily basis...
Phytoestrogens are naturally occurring in a wide variety of foods that we eat everyday.
Generally speaking, phytoestrogens are found in foods such as whole grains, beans, peas, seeds, fruits and vegetables. So like I said, we get a lot of phytoestrogens in the foods we eat everyday! However, the phytoestrogenic “potency” changes based on what food we’re talking about, with some foods having more phytoestrogenic effects than others. Flax seed contains the highest total phytoestrogen content followed by soybean and tofu. (4)
If you’re looking for a more in depth list of foods that contain phytoestrogens, here it is: soybeans, tofu, tempeh, soy beverages, linseed (flax), sesame seeds, wheat, berries, oats, barley, dried beans, lentils, rice, alfalfa, mung beans, apples, carrots, wheat germ, ricebran, broccoli, cauliflower and the list goes on! (2,4) If you’re eating a whole food diet,you can pretty much guarantee you’re getting a variety of food sources of phytoestrogens on the daily.
Lignans and Isoflavones: Breaking Down the Terms
If you do any research into phytoestrogens, you’ll come across these two terms: Lignans and isoflavones. Basically, these are two types of phytoestrogen molecules, and they differ depending on their source. To keep it simple, let’s break it down- Common phytoestrogens found in fruits (berries, apples), whole grains (barley, wheat, oats, rice) and seeds (sesame seeds, flax seed) are called lignans.
Phytoestrogens found in soy products like tempeh, tofu & soybeans, as well as in other legumes (mung beans, lentils) and peas, are called isoflavones.(2) They’re different molecules, but both act on the estrogen receptor, as we’ll discuss next!
How Do Phytoestrogens Work In the Human Body, Then?
When humans intake phytoestrogens, it has a very interesting effect. According to Dr. Jill Stansbury, phytoestrogens “bind to estrogen receptors acting as either agonists or antagonists, depending on the physiologic situation.”(1) This speaks to the fact that phytoestrogens have the capacity to balance high estrogen environments, as well as low estrogen environments, depending on what hormone pattern is present. “This dual action of phytoestrogens, to both offer estrogenic support in some situations and reduce excessive estrogen stimulation in others, is referred to by herbalists as amphoterism.” (1)
Amphoteric, is a term that comes to us from chemistry, that describes a substance that can act as both an acid and a base, depending on the situation. In herbal medicine, amphoteric, is a term used to describe a herb that “acts in two seemingly different ways, to bring about balance to the body. It harmonizes and normalizes the function of an organ or body system, balancing the two seemingly contradictory conditions such as diarrhea and constipation, or high and low blood pressure, for example.” (2) In the case of hormone health, this amphoteric effect makes phytoestrogens a fantastic and widely applicable holistic strategy for bringing balance to both low estrogen and high estrogen situations.
Interestingly (and not surprisingly!), when synthetic phytoestrogen-like compounds have been tested, they don’t have the same amphoteric action as naturally occurring phytoestrogens. (1)
Phytoestrogens Can Decrease Estrogen Excess Symptoms...
The way that phytoestrogens work is they fit into our own endogenous estrogen-receptor sites, which essentially “blocks” our own estrogen from binding. Endogenous is just a fancy biology word that means, “growing or originating from within an organism.” So our bodies make our own estrogen, it circulates around and fits into estrogen receptor cells, which results in specific “estrogenic” effects in the body. Our own body’s estrogen is much stronger than phytoestrogens, though. When phytoestrogens fit into the estrogen receptor site, they have a “weaker” estrogenic effect, while blocking the “stronger” estrogen (our own) from binding. This means when there is a picture of excess estrogen in the body, there is an overall decrease in estrogenic effects system-wide. Pretty cool, hey?
Conditions thought to be the result of excess estrogen, often referred to as “estrogen dominance”, include: uterine fibroids, endometriosis, polycystic ovary syndrome (PCOS) (in some presentations), fibrocystic breasts, PMS (premenstrual headaches, mood changes, bloating,etc) and more. (9)
Phytoestrogens Can Help Increase Estrogenic Effects, When Needed Too!
In the case where estrogen might be low, like in menopause let’s say, phytoestrogens can be really supportive in creating more estrogen-like effects in the body. Remember how phytoestrogens fit into the estrogen receptor site? Well, if there is a lack of estrogen to stimulate those receptors, then the phytoestrogens will fill the receptor sites to stimulate an increase in estrogenic effects, system-wide. Make sense? Also, pretty amazing, right?
The completely natural phase of life that comes with an equally natural dip in estrogen is menopause. Menopausal symptoms may benefit greatly from the addition of phytoestrogens to the diet and herbal protocols.
What Herbs Contain Phytoestrogens?
I’m so glad you asked! Phytoestrogens are a specific category of herbs, meaning not all herbs contain phytoestrogens. Knowing which herbs are rich in phytoestrogens can be super helpful along your herbal journey. Here’s a list that summarizes some of the main ones.
My Favorite Phytoestrogenic Herbs:
- Hops (Humulus lupulus)
- Red Clover (Trifolium pratense)
- Sage (Salvia officinalis)
- Alfalfa (Medicago sativa)
- Licorice (Glycyrrhiza spp.)- (not a herb I automatically think of as a classic phytoestrogen, but mounting body of research shows that it does fit the estrogen receptor site! (5))
There are quite a few herbs that have shown potential phytoestrogenic effects, but this research is ongoing and the way they interact in the human body continues to be explored. (14)
A Note On Chasteberry (Vitex agnus-castus)
In herbal medicine, we use Vitex to modulate estrogen, meaning it has the effect of bringing estrogen back into balance, whether high or low. And while some of the research shows phytoestrogenic activity, it’s thought that the hormone-balancing effect of Vitex is caused by its direct action on the pituitary gland- that part of our brain that plays a key role in hormone messaging. (7,8) To get really specific, the mechanism of action is presumed to be it’s effects on the dopamine receptors, which results in changes of prolactin secretion from the anterior pituitary. Interestingly enough with Vitex, how much you take will affect the final hormone balancing effects. At low doses, “it blocks the activation of D2 (dopamine) receptors in the brain by competitive binding, causing a slight increase in prolactin release. In higher concentrations, the binding activity is sufficient to decrease the release of prolactin.” (10). Ok, so if you just totally glazed over and that went way over your head, don’t worry about it and just come back to me! That was for all of my herbal science nerds out there. The main takeaway here is that herbs are complex! The way they interact in the body can be multifaceted, and just because a herb acts on the hormones doesn’t necessarily mean it’s a phytoestrogen.
A Note on Black Cohosh (Actaea racemosa)
Black cohosh is another plant that we use in herbal medicine to regulate estrogen, and can be found in almost all formulas for menopausal symptoms, among other hormone balancing formulations. However, the thought that Black Cohosh contains phytoestrogenic compounds, and acts through that mechanism is a myth. (6). According to research, “extracts of Black Cohosh do not contain estrogenic compounds: they exert their efficacy through mechanisms linked to the presence of dopaminergic, noradrenergic, serotoninergic and GABAergic acting substances, but no estrogenic activity can be expected.” (6) This points to the effects that Black Cohosh has on important neurotransmitters, another very interesting discovery!
So to summarize- there are many herbs that can help to balance hormones, and while many of these herbs can help to balance estrogen, they do so through a different mechanism of action, not because they’re phytoestrogenic.
How Do I Know Which Phytoestrogenic Herb To Pick?
First, you want to keep the other medicinal properties of the herb in mind. Hops, for example, are gently sedative and can be a great ally when there is insomnia, sleep disturbance, anxiety or any need to calm the nervous system. Red clover, on the other hand, is really nutritive and can help clear up skin issues. Remember, herbs have multiple effects and actions in the body, which is part of why they’re so incredibly healing! Choosing phytoestrogens that have the positive “side effect” of helping other health issues present, is the best way to get the full medicinal effect of a specific herb.
Second, you want to keep the energetics of the plant in mind. This is where it can take a little more experience to understand the nuances of how a plant will impact a person’s “internal terrain”, also known as they’re constitution type. Here’s what I mean by “herbal energetics”: Does the herb help to moisten tissues, or dry them out? Is it heating or cooling? Does it encourage relaxation or constriction? All of these qualities will be needed in different situations, depending on the person, and can be an important part of finding the right “match” for every individual.
Wait, Are Phytoestrogens Safe for Estrogen-Sensitive Cancers?
Over the years, there has been much debate about whether or not natural sources of estrogen (food and herbs) have the same negative impact as synthetic or xenoestrogens (harmful environmental compounds capable of binding to estrogen receptors), as it relates to hormone-sensitive cancers. Dr. Stansbury states: "Only a decade ago the use of phytoestrogens at all for cancer patients was controversial and of concern to practitioners due to valid concerns over possible proliferative effects on hormone-sensitive tissues. As research mounts, not only do phytosterols appear safe for consumption by patients with previous or existing hormonal cancers, but they also appear to have preventative and clinical benefits for breast and prostate cancer patients." (1)
Yes, phytoestrogens bind to estrogen receptor sites to stimulate a weak estrogenic effect in the body, but "the research is mounting that such hormonal actions do not overstimulate hormone dependent cancers, and at the present time, phytoestrogens appear to be valuable tools to include in the overall treatment protocols for breast, prostate and other hormonal cancers." (1)
Crawford adds: "Many women are told to stop taking estrogenic herbs because their doctors do not understand what experienced herbalists know about these herbs. Herbs with plant hormones do not behave like hormone drugs. Some studies suggest that phytoestrogens can decrease the risk of cancer, presumably by competing with (endogenous) estrogen." (12)
The regular consumption of soy products in the diet seems to lower the risk of developing breast cancer, and the protective effects are mostly attributed to the phytoestrogens. (11) One meta-analysis (compilation of many studies), reported that 2-3 servings of soy daily (containing 25-30mg of isoflavones- a plant-based constituent present in leguminous herbs) "offered protection against breast cancer and its recurrence." (1)
There are definitely some practitioners who still adhere to the "approach with caution" mindset in regards to phytoestrogen use. Dr. Romm, midwife, herbalist and medical doctor, takes a more conservative approach to phytoestrogens and says: "The relationship between breast cancer and phytoestrogens appears to be dependent on a number of variables, including age at exposure, individuality in metabolism, endogenous (natural estrogen in the body) hormone levels, form in which phytoestrogens are consumed (i.e. as supplements or foods), and whether soy products are fermented, which may increase bioavailability. Adolescent exposure to soy products seems to be one key to its protective effects against breast cancer." (13) She goes on to say that there is still doubt around exactly how phytoestrogens affect increased breast cancer risk, but that there is no evidence demonstrating harmful effects when phytoestrogens are incorporated as part of a well-balanced diet including tempeh, tofu, soy, flax, and in fact can have "health promoting effects".
She cautions that "supplemental phytoestrogens, however, is not advisable, particularly for women with a history of breast cancer or breast cancer risk." (13)
Therefore, in summary, if you are someone who has a history of hormone-sensitive cancers and/or are at risk due to a strong family history and you'd like to be cautious, it appears dietary/natural sources of phytoestrogens (including preparations of herbs in their natural form i.e. no isolated constituents or concentrated extraction of specific compounds) can prove to be protective. However, using supplements (that may concentrate the phytoestrogenic constituents), may be something to avoid.
Dr. Stansbury adds: "It is not a good idea to consume an abnormal amount of phytosterols (phytoestrogens), but the consumption of beans is not contraindicated, nor is the use of herbal medicines to manage menopausal symptoms in women with a history of breast cancer or those experiencing surgical menopause. There is no evidence that the consumption of leguminous herbs or dietary soy and other beans causes harm, but research is ongoing to confirm safety in all circumstances.” (1)
Disclaimer: Of course, patients with a history of hormone-sensitive cancers should always consult with a knowledgeable physician and/or specialist. This information is for educational purposes only and is not meant to replace care from your primary care giver.
And with that, we’re at the end of our phytoestrogen journey! I hope this information was helpful.
As always, signing off with all my wild herbal love,
READY TO GET TO THE ROOT CAUSE OF YOUR HEALTH ISSUES, NATURALLY? BOOK A CONSULTATION WITH ME SO WE CAN DO IT TOGETHER!
- Stansbury, J. (2018). Herbal Formularies for Health Professionals. Volume 3: Endocrinology.
- Yardley, K. Traditional Herbal Medicine Terminology: Amphoteric
- Breast Cancer Prevention Partners (BCPP). Phytoestrogens
- Saljoughian, M. Focus on Phytoestrogens. US Pharm. 2007;32(12):HS-27-HS-32.
- Hajirahimkhan, A., Simmler, C., Yuan, Y., Anderson, J. R., Chen, S. N., Nikolić, D., Dietz, B. M., Pauli, G. F., van Breemen, R. B., & Bolton, J. L. (2013). Evaluation of estrogenic activity of licorice species in comparison with hops used in botanicals for menopausal symptoms. PloS one, 8(7), e67947. https://doi.org/10.1371/journal.pone.0067947
- Wuttke, W., Seidlová-Wuttke, D. Black cohosh (Cimicifuga racemosa) is a non-estrogenic alternative to hormone replacement therapy. Clin Phytosci 1, 12 (2015). https://doi.org/10.1186/s40816-015-0013-0
- Examine.com: Chaste Tree (Vitex angus-castus)
- Carmichael AR. Can Vitex Agnus Castus be Used for the Treatment of Mastalgia? What is the Current Evidence? Evid Based Complement Alternat Med. 2008 Sep;5(3):247-50. doi: 10.1093/ecam/nem074. PMID: 18830450; PMCID: PMC2529385.
- Dr. Christian Northrup: Estrogen Dominance
- Grant, P., & Ramasamy, S. (2012). An update on plant derived anti-androgens. International journal of endocrinology and metabolism, 10(2), 497–502. https://doi.org/10.5812/ijem.3644
- Trickey, R. (2003). Women, Hormones & the Menstrual Cycle.
- McQuade Crawford, A. (2009) The Natural Menopause Handbook.
- Romm, A.(2014) Botanical Medicine for Women's Health.
- Phytoestrogens: A review of the present state of research (2003)