As far as plant-based staples go, few foods are as prominent as tofu. Versatile and packed with protein, it offers a tasty alternative to meat dishes. We use it in stews, burgers, breakfast dishes, sauces, and even desserts, thanks to its ability to take on any flavor profile we wish to give it.

However, despite its apparent popularity, tofu and soy’s appeal can be controversial. You may have come across people who steer clear from including it in their diet or questioned your own consumption at some point due to the criticism surrounding phytoestrogens, which are found in soy products.


Not sure where you stand on the issue? You aren’t alone. This is why we’re bringing you all the cold hard facts from recent research about soy and their impact to let you make your own educated decision.

Without further ado, here is everything you’ve ever wanted to know about tofu and phytoestrogens along with the addition of formidable resources from the Food Monster App to help you dig deeper.

What Are Phytoestrogens?Vegan Ginger Garlic Tofu Curry in sauce with garnish

Ginger Garlic Tofu Curry/One Green Planet

Phytoestrogens are a group of plant compounds that are naturally present in a wide variety of foods such as fruits, vegetables, grains, nuts and seeds, and herbs. They’re found in a significantly higher concentration in soy products like soybeans, tofu, tempeh, and miso.


Phytoestrogens are made up of four main types of chemical compounds: isoflavonoids, stilbenes, coumestans, and lignans.

As their name implies, these plant compounds are functionally and structurally similar to estrogen, an essential hormone produced by the human body, especially important to the female reproductive system.

Hormonal Impact of PhytoestrogensTurmeric Tofu Cashew Curry

Turmeric Tofu Cashew Curry/One Green Planet

Due to their inherent similarity with estrogens, concerns about the impact of phytoestrogens on the human body are mostly centered around hormones and the endocrine system. More importantly, the consequences that possible disruptions to our hormonal functions could have on our health.


An important piece of the puzzle lies in the impact that phytoestrogens have on our estrogen receptors. Estrogen receptors in the human body exist as two subtypes: ER alpha and ER beta. While the two receptors have overlapping roles, they are also unique.

By example, in one of the most well-known detrimental impact of hormonal dysregulation and over-activity of estrogen — breast cancer — ER alpha receptors are subject to over expression. On the flip side, ER beta show a suppressing effect on this malfunction which could potentially offer anti-carcinogenic benefits.

When it comes to phytoestrogens or ‘plant estrogens’, their modulating effect — and potentially positive or negative impact alike — is dependent on the estrogen receptors they target.

Want to know more about these natural compounds? Let’s explore the intricacies of the main types of phytoestrogens:


1. Isoflavonoids

Isoflavonoids or ‘isoflavones’ are not only part of the phytoestrogens family but they are also defined as dietary antioxidants. As such, they play a role in diverse biological functions, from preventing oxidation to regulating our immune system functions.

The effect of isoflavonoids is mediated by the extent of their bioavailability which is influenced, among other things, by our individual gut microbiome. During the digestive process, isoflavones are converted further into metabolites by our intestinal bacteria. These broken down isoflavonoids named ‘equol’ have the ability to bind with estrogen receptors. It is estimated that those ‘equol’ compounds are produced in around 30 percent of people who consume soy.

Research suggests that a high presence of ‘equol’ and other isoflavonoids compounds have a positive impact on hormone related breast cancer risk in women.

2. Stilbenes

Like isoflavonoids, stilbenes are classified as potent antioxidants. Part of the polyphonols family, these natural compounds are anti-inflammatory and have the ability to promote apoptosis (cell death) while also fighting free radicals, Thanks to these properties, stilbenes show promise in the treatment of multiple diseases, especially cancer.

The exact biological activity of stilbenes remains partly misunderstood to this day, mostly because of their low bioavailability (meaning they are quickly metabolized by the body). Research however indicates that this type of phytoestrogens compounds are indeed anticancer agents.

3. Coumestans

Coumestans are produced by the oxidation of pterocarpan, a compound derived from isoflavonoids. Similar to this type of phytoestrogens, coumestans can bind with estrogen receptors.

Although few ‘in vivo’ studies exist to give support to the anticancer effects of coumestans, numerous ‘in vitro’ data suggest their toxicity to cancer cells.

4. Lignans

Similar to isoflavonoids, lignans compounds are dependent on our gut microbiota for their production. Enterolactone and enterodiol, the two major lignans metabolized by our gut bacteria have estrogenic properties, which means that they impact hormonal functions within our bodies.

The activities performed by lignans are far reaching with studies showing their anti-cancerous, antioxidant, anti-inflammatory, and antihypertensive effects.

Factors to Consider

Southern-Fried Tofu With Maple Dill Sauce/One Green Planet

Although phytoestrogens compounds show beneficial properties, their ‘in vivo’ efficacy may be dependent on certain factors.

As mentioned previously, our gut microbiota and the beneficial bacteria it contains is important to the production of phytoestrogens-derived compounds that may exert a protective effect against hormone-related diseases. Considering that estimates posit that around 30 percent of people in the Western world (versus 60 percent in Asian population) posses a digestive track that gives rise to a high bioavailability of certain phytoestrogens, their benefits become less apparent.

Some research also suggests that the age at which one consumes phytoestrogens is a factor, along with genetics. Namely, having a diet high in phytoestrogens before adulthood might have a bigger protective impact in breast cancer.

In short, consuming tofu or soy products and having a diet high in phytoestrogens doesn’t necessarily have a positive impact on our health but there is also no clear cut evidence pointing to the contrary.

How do you feel about soy? Is it an important part of your plant-based lifestyle? Let us know in the comments!

Recommended Resources and RecipesSuper Easy Hoisin Tofu

Super Easy Hoisin Tofu/One Green Planet

Want to know more about the health benefits of plant-based foods and how to cook delicious meals? Here are a few articles that might interest you:

Also, if you’re looking for more information on plant-based living, healthy recipes, as well as cooking tips, we highly recommend downloading the Food Monster App, which is available for both Android and iPhone, and can also be found on Instagram and Facebook. The app has more than 10,000 plant-based, allergy-friendly recipes, and subscribers gain access to new recipes every day. Check it out!

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