Opinions on them differ. According to some, they may have negative side effects for men when consumed in excess. Many males want to know how to decrease estrogen intake for that reason. On the other hand for women, many firmly believe the foods/supplements benefit their post-menopausal symptoms like hot flashes and therefore want to increase intake. Research suggests they might help lower risk for osteoporosis, breast cancer, and heart disease (1).
What are phytoestrogens?
In humans as well as animals, the most important sex hormone is estrogen. Not only is it vital in the development and health of the female reproductive system, but also secondary qualities such as some appearance traits that our culture typically will associate with as being feminine, such as breast size and shape.
Phytoestrogens are created by plants. They are not the same estrogen created by humans. Rather they are a form of xenoestrogens, which means even though they are different, they do have the ability to imitate some effects of human estrogen when in our body.
Many women want to know how to increase estrogen levels naturally during menopause or for fertility. That question – and the marketing which infers it’s possible with these plant-based compounds – is a bit misleading. Why? Because even though many doctors advise their patients to treat low estrogen levels with supplements and certain foods, those don’t actually change how much you have of the natural human hormone. That will remain low and continue decreasing with age.
According to researchers, what the phyto forms do when they’re in the human body is replicate some effects of the real thing. So even though they don’t increase estrogen production, they might produce similar results as if that person’s body was naturally producing more.
Another form of xenoestrogens are man-made synthetic chemicals such as BPA, DDT, phthalates, PBB, and atrazine. With the exception of DDT (which has been banned in the US since 1972), these are commonly found in plastics, pesticides, pharmaceuticals, and beauty products. In fact, there’s a good chance the mouse you’re holding in your right hand or the iPhone/iPad you’re holding as you read this has these in it. Fortunately, you’re not eating them.
However unlike what’s found in natural phytoestrogen foods, the synthetic man-made chemicals like BPA carry a whole array of other characteristics which affect your endocrine (or hormone) system. Both females and males should decrease/minimize exposure to them as much as possible. In short, the natural plant forms are considered safe in moderation, the man-made are not good in any amount because of their other potential side effects.
Everyone is obsessed with BPA in canned foods and bottles, but there is a far more common source they totally ignore.
Much more common is a non-dietary source you encounter multiple times per day, one that is likely to be entering your blood steam through your skin. It’s the coating on thermal receipt papers. That slightly wet and sticky film covering the receipt is loaded with xenoestrogens. In one study, over 80% of receipts tested contained BPA (2).
Next time the cashier tries handing you a receipt, tell them to put it in the bag. At the restaurants where you pay for the food before eating, it’s probably best to say “no thanks” when they hand it to you (that’s what we do). You don’t want BPA on the same fingers you’re holding your sandwich with.
Wash your hands you say? Well, that study did specifically state “it can enter the skin to such a depth that it can no longer be washed off.” If you wait on touching the receipt until 2 hours after it was printed, you should be good as the drying decreases how absorbable it is.
Of course, how much (or how little) the natural and synthetic versions affect us is a hotly debated topic.
Types of natural estrogen in food
It’s important to realize that plants aren’t the only dietary source. There is also estrogen content in animal-based foods such as meat, dairy, eggs, fish, and seafood. To date almost all research has focused on the plant-derived versions and “very little” research has been conducted on animal sources, which is “leading to an underestimation of intake” according to paper published in the Journal of Agricultural and Food Chemistry (3).
In addition, there are fungi estrogens; mycoestrogens. Like those coming from animals, these have very little research relative to plant sources. Mushroom mycoestrogens from dietary sources of fungus (i.e. the white button or portabella mushrooms we eat) aren’t a concern so far in terms of having a biological effect in the human body. Rather, what is a definite concern are some types of fungi which grow on contaminated grains – either prior to harvest or during storage – that have the potential to produce mycotoxins which can be dangerous to humans (4).
Research has suggested these grains contaminated may interfere with the growth of adolescent girls, including their height and breast tissue growth (5).
Top 3 types in plants
They are actually a specific type of isoflavonoids. However when talking about estrogen foods like soy, most people use the word isoflavonoid rather than the sub-category name isoflavones.
Among the dietary sources of estrogens, the vast majority comes from isoflavones. For example, if you look below at how much phytoestrogen is in soy milk, you will see that 99.6% comes from the isoflavones category. The remaining comes from lignans (0.4%) and a minuscule amount from coumestan (it’s actually 0.0% when rounded). The breakdown of how much is in soy like tofu, edamame, and tempeh follows a similar pattern.
When it comes to natural herbal remedies to increase estrogen levels overall (the amount produced by the body + plant sources), many if not most supplements use isoflavones.
The most common types of isoflavones found in food are daidzein, formononetin, genistein, glycitein, and biochanin A.
Even a layman will notice how their chemical structures are quite similar, so it’s understandable why they may have a similar biological affect. How much their differences affect the bio-activity of xenoestrogens in the human body is not a black and white answer. Both sides have good evidence to back up their positions.
That may be because the sensitivity to them can differ greatly between genders and individuals. For example in men, how high or low their natural testosterone level is to begin with would presumably affect whether or not the dietary and environmental exposure to estrogen is high enough to cause side effects. Research also suggests there may be more safety concerns for babies, boys, and teens versus grown men (6). Avoiding unnecessary increased exposure in young males may be a good idea.
This is the 2nd most common phytoestrogen. The lignan category includes pinoresinol, lariciresinol, secoisolariciresinol, sesamin, hydroxymatairesinol, matairesinol, and syringaresinol.
As the name implies, sesamin is from sesame seeds and it’s the only place you will find it. Since we eat very little in our diet (only a few seeds sprinkled on a bagel or muffin), the process of extracting these lignans and using them in sesamin supplements is one way they’re used.
However the most popular choice among women who want a natural estrogen supplement remains to be plant sources other than sesame. For example, these bestsellers use black cohosh, soy, and/or other forms which lend themselves better to dietary supplements and creams:
How much lignans are in flaxseed? It represents the bulk of their content; 99.9%. The remaining 0.1% comes almost entirely from isoflavones, as you would have to go out several digits right of the decimal point to represent the percentage coming from coumestan. Even when you compare flax versus soy, by a landslide flax wins as the food highest in estrogen. That fact, combined with its high omega 3 content, makes it a popular choice among women for how to increase intake.
Others high in lignans include sesame, grains (e.g. rye, wheat, oat, barley), brassica vegetables (e.g. kale, Brussels sprouts, cabbage, cauliflower, collards), and red wine. However it’s really not fair to compare flax and sesame versus the other sources, since they contain amounts which are exponentially more.
A study done at Abo Akademi University in Finland analyzed lignan content in 24 sources. Here are a few samples.
|Examples of Foods Rich In Lignans (amounts in µg per 100g)|
|SEC = secoisolariciresinol
SES = sesamin
PIN = pinoresinol
HYD = hydroxymatairesinol
LAR = lariciresinol
SYR = syringaresinol
MAT = Matairesinol
Source: Smeds AI, Eklund PC, Sjöholm RE, et al. Quantification of a broad spectrum of lignans in cereals, oilseeds, and nuts. J Agric Food Chem. 2007;55(4):1337-46. (7)
Even though the bran of grains contains a lot, most breads made from grain will contain very little.
This is because bran is the outer husk which is removed during the milling process, the remainder (what’s inside) is the flour that is ground into powder and used for baked goods. As you will see in the phytoestrogen food chart below, the measurements in breads are very low. The flour itself contains almost none and any found in it is likely coming from remnants of the bran.
However, breads made with bran (i.e. multigrain) may contain large amounts.
The least common phytoestrogen are coumestans. You won’t find a supplement or cream using it as the primary active ingredient. In almost all foods that contain estrogens, the coumestans represent less than 1% of the total.
The exception to that rule are some legumes, especially beans. That’s where you will find coumestan in higher concentration, up to 30% of the total phytoestrogen content. Examples include split peas, lima beans, mung beans, and pinto beans. Regardless, all of the aforementioned are a relatively low dietary source and most would have only a negligible impact of increasing estrogen. With the exception of soy, as you will see below not many beans even make the top 50 and for those that do, most are near the bottom of the food chart.
Top 50 phytoestrogen foods list
Most people are aware that soy products such as tofu and edamame are natural sources, as they are particularly rich in the isoflavones genistein and daidzein. Though aside from soybeans, both women and men are largely unaware as to the phytoestrogen herbs and foods they may be consuming on a daily basis.
Whatever your opinion on them may be, you should have a right to know if you’re eating a food with high amounts. Males are more likely to avoid them, while some females want more in their diet and others may wish to minimize or avoid consumption due to safety concerns. Unfortunately, manufacturers fail to disclose this information and U.S. labeling laws do not require or even allow it to be stated within the nutrition facts box.
Below is a chart of the 50 highest natural sources to help you identify what to include in your diet (or not) depending on your preference. Many women swear by estrogen rich foods for menopause symptoms. Some medical opinions go so far as to “emphasize the need for the intake of foods containing” them because they reportedly “can take out the postmenopausal indications to a large extent” such as hot flashes (8). Whether or not they can help hormonal imbalances is something you need to discuss with your doctor before ever using them for that purpose.
These amounts are based on a study that was conducted at the University of Toronto (source details at bottom). In the study, they analyzed a total of 121 common foods relevant to the Western diet that were known to contain the phyto form. Many would call these estrogen increasing foods, but please understand the researchers only measured how much is in them and not how they react in the human body.
A couple caveats:
- Being that it’s only found in one dietary source, they didn’t measure sesame seed lignans (i.e. sesamin). For that reason, it ranks #10 on their list. However if you added in the sesamin content, sesame would really rank at #2.
- Flax will always be highest, but here the amount of lignans was substantially more than in the Finnish study discussed above. Possible reasons for this may be that the Toronto study used a high-lignan flax and/or the Finnish study used a different form of the seed (whole versus shelled flax seed, etc.).
|Foods High In Phytoestrogens (amounts in µg per 100g of food/beverage)|
|6.||Textured veggie protein (soy)||2.4||16,122.2||99.4||16,223.9|
|9.||Soy protein powder||0.5||8823.8||16.5||8840.7|
|10.||Sesame seeds||0.4||10.5||7,997.2 (excludes sesamin)||8,008.1 (excludes sesamin)
|12.||Soy bacon bits||nd||5,998.6||35.1||6,033.7|
|13.||Black bean sauce||0.6||5,319.2||10.5||5,330.3|
|18.||Soy veggie burger||0.2||1,656.0||15.2||1,671.5|
|22.||Soy bean sprouts||nd||787.5||2.2||789.6|
|24.||Mung bean sprouts||136.6||229.8||128.7||495.1|
|Source: Phytoestrogen content of foods consumed in Canada, including isoflavones, lignans, and coumestan (9)
Authors: Thompson, L.U., Boucher, B.A., Liu, Z., et al.
Publication Name: Nutrition and Cancer
Publication Details: Volume 54, Number 2, Pages 184-201. The 50 highest sources are reflected above. You may purchase/access the report here consisting of 191 foods in total, which includes granular details for each such as the types of lignans and isoflavones as well as a breakdown of their amounts (formononetin, daidzein, genistein, glycitein, matairesinol, lariciresinol, pinoresinol, secoisolariciresinol).
Which foods to avoid if you’re a man?
The good news is that for men who are afraid of affecting their hormones, they really don’t need to cut out a lot.
Since herbs, spices, and nuts aren’t potent sources, it really simplifies the situation by not having to worry about those. True, garlic is #23 on the list, but remember it’s how much that’s found in 100 grams worth (3.5 ounces). In a meal, it’s unlikely you’re even consuming 1/10th that amount of garlic, which would put the phytoestrogen intake at less than a glass of red wine (5 ounces is average glass size). No one would really consider that an estrogen increasing food.
Since the top 10 or 20 foods have exponentially more than even the top ranked fruits, nuts, and vegetables, a man can dramatically reduce the amount he eats simply but cutting the foods highest in estrogen. Being that 8 of the top 10 are soy, reducing or eliminating that alone will already be a huge improvement.
For those who enjoy tempeh, tofu, and the like, unfortunately cooking is not a viable method for how to decrease estrogen in males. In fact, the production of tofu already involves boiling soybeans for an extended period of time and as you saw in the above table, its levels are still extremely high.
For a cheat sheet, just remember this listing of 5 estrogen foods to avoid or eat less of:
- Flax – Avoiding oatmeal, cereals, and snacks that include this seed. Given that it’s the highest food by far, this one should be prioritized. You may want to avoid flax milk and use almond milk instead. Need another good omega 3 source? Use walnuts, which contain only 0.04% of the amount of phytoestrogens in flax seeds (those have nearly 3,000x more).
- Soy – Whether your tofu is organic or not will make no difference. All soy products will naturally have large amounts.
- Sesame – The tiny amount sprinkled on a bagel or burger bun shouldn’t concern you. However you may want to tread carefully with sesame crackers and similar foods using rich amounts.
- Brans – It’s why multigrain bread cracks the top 20. Luckily most offenders will have the word bran in their name – bran muffins, Raisin Bran, etc. Some will not though, like certain types of Fiber One bars. The phytoestrogens in bread using milled flour should be trivial.
- Doughnuts – Singling these out for the top 5 may not be fair, but we figure it might be good motivation for you to eat fewer doughnuts!
Vegans and vegetarians are more likely to have higher amounts in their diets. The men here at Superfoodly who are vegan try to consume tofu/tempeh no more than 2-3 meals per week for that very reason. It’s not always easy to do since it’s the cheapest meat alternative and hence, the most common plant-based option offered at restaurants.