Soy menopause side effects

I answer the question, is soy bad for you? A look at the research on the dangers of soy and menopause, breast cancer and heart health!

With the popularity of kale salads, juice cleanses and smoothie bowls, it’s no surprise that vegetarianism and veganism have become the diet du jour this year. And since a girl can’t live on produce alone (well unless you’re Freelee the Banana girl), plant-based sources of protein have become all the rage. Without meat, fish, eggs, or dairy, soy products (think edamame, tofu, miso, soy milk, and soy cheese) are now a more mainstream staple in the health-conscious foodies diet, but with them have come a lot of questioned about their impact on health. So is soy bad for you? Does it cause breast cancer? Let’s dig into the research.

Why Do People Think Soy is Bad for You?

It all comes down to the fact that soy contains compounds called isoflavones (a phytoestrogen) that mimics our body’s natural (endogenous) estrogen, so many people wonder what this so-called “artificial” hormone does in our body. Let’s start by looking at how estrogen works in our body. First of all, we have two types of receptors specific to endogenous estrogen in our human cells – estrogen receptor-alpha and estrogen receptor-beta. Different parts of our body have different amounts of each receptor. The isoflavones found in soy are selective estrogen receptor modulators (SERMs), which means that sometimes they act like estrogen and sometimes they do not. One study found that our natural hormone estrogen will bind to both receptors but isoflavones prefer to bind to the beta receptors. This study found that there is competition between the isoflavones and endogenous estrogen for the receptors. Interestingly, while isoflavones can mimic the effects estrogen and bind to estrogen receptors, they also have a weaker estrogen effect than the estrogen our bodies makes.

OKAY. So now that we know soy contains plant-estrogens (isoflavones) that sometimes act like estrogen, sometimes don’t, and sometimes even inhibit endogenous estrogen from binding to estrogen receptors… What does that mean for helping us answer the question is soy bad for you? There are three main areas that we will look at where isoflavones and soy may play a role: menopause, breast cancer, and cholesterol.

dangers of soy and menopause

Hot flashes, night sweats, dry vaginas, OH MY! These common symptoms of menopause sound pretty brutal but early research suggests that including soy in our diets may help us find relief!

While women no longer have to deal with their periods during menopause, this also means that our ovaries make less estrogen. These hormonal changes cause the uncomfortable side effects. The Journal of Obstectrics and Gynaecology Canada’s have created guidelines on managing menopause, which include estrogen hormonal therapy as one way to deal with these dreadful symptoms. There are, however, some risks involved with long-term use of hormonal therapy including increased breast cancer risk. Your doctor would be able to discuss these risks with you before prescribing any of these treatments.

A meta-analysis of 15 randomized control trials found that dietary isoflavones decreased the number of hot flashes with no serious side-effects. Another meta-analysis, that included 62 different studies and over 6000 women, found that phytoestrogen ingestion reduced hot flashes and vaginal dryness but did not have any effect on night sweats. The study also found similar results using dietary soy isoflavones and isoflavone supplements. However, it is very important to note that soy has not been found to be effective replacement to hormone therapy and there are mixed and limited data on the effectiveness of isoflavones for menopausal relief. Sorry ladies.

It looks like while there might be some good news in the future for some of us women on soy protecting against some of the uncomfortable side-effects of menopause, but there still needs to be more research before we know for sure.

dangers of soy and Breast Cancer

The American Cancer Society suggests that estrogen plays a role in breast cancer. Similar to how estrogen-replacement/hormonal therapy can increase the risk of breast cancer in post-menopausal women, women who have had more exposure to estrogen over their lives (due to having their periods early in life or starting menopause later, for example) are at increased risk of developing breast cancer. This leads us to question the safety of consuming estrogen-like compounds (isoflavones) in soy.

One of the drugs that is used to treat breast cancer works by binding to estrogen receptors, much like how isoflavones bind to selective estrogen receptor modulators (SERMs). Here comes the potential role of isoflavones. If you recall, isoflavones compete with endogenous estrogen for the estrogen receptors, are more likely to bind to some of the receptors but have weaker effects, and act somewhat like the drugs used in treatment.

One research review looked at 24 different studies examining the link between soy and breast cancer. Eight of the studies found no link between eating soy foods and risk of breast cancer while 12 of the studies found that there was an inverse association between consuming soy and breast cancer risk. In other words soy may lower the risk of breast cancer. One of the studies included over 36 000 post-menopausal women from the Multiethnic Cohort Study and they found that those who ate a diet with lots of soy products, and subsequently isoflavones, had a reduced risk of post-menopausal breast cancer. The authors of the review concluded that soy seems to play some sort of protective role in reducing the risk of breast cancer.

Another review had similar findings suggesting that a diet high in soy (defined as 13 grams soy protein per day) compared with diets with a low soy did not change the risk of initial breast cancer but does decrease the risk of death by 15% and recurrence by 25%. Another group of researchers found that moderate soy protein (5-10 grams everyday) was the most beneficial for people who already have been diagnosed with breast cancer.

So in conclusion, is soy bad for you if you’re prone to breast cancer? At this point, it seems that soy is safe for consumption after a breast cancer diagnosis (unless otherwise instructed by your doctor), but we need more research before there are recommendations about soy preventing future incidents of breast cancer. Part of the reason for this is because a number of studies found no link between soy consumption and breast cancer. The American Cancer Society recommends that as long as soy is consumed from food in moderation (3 servings per day), it is safe to eat/drink. However, there is not enough research to know whether soy supplements are safe for use following breast cancer and in fact, the American Cancer Society recommends avoiding high supplement doses. We also do not know exactly how much soy protein is beneficial. Clearly more research is certainly needed to answer questions on how much and whether soy is actually protective against breast cancer risk.

dangers of soy and Heart Health?

There was recently an article in the Financial Post talking about the growing soy industry in Canada due to a newly approved Health Canada Health Claim. The claim explains that products containing at least 6 g of soy protein can claim that their product helps lower cholesterol levels. If you are looking for the benefits of lowering cholesterol by eating soy protein you want to aim to eat at least 25 grams of soy protein per day.

Other Dietary Concerns and Soy

If you are following the Paleo diet, soy is technically a legume and is not paleo-approved. You can read more about the ins and outs of Paleo here.

If GMOs are a concern, we know from our first article on GMOs that soybeans are one of the most commonly found GMO crops in Canada. The good news is – there are both GMO and non-GMO soy products out there, so no matter your GMO preferences (or lack thereof), you can reap the benefits of soy protein!

Where to get Soy Protein?

Now that we know soy has some health benefits and does not increase our risk of breast cancer, let’s talk about where we can find soy protein in our diets!

Some people may say soy makes us fat, but they are not talking about WHOLE foods, they are talking about processed foods that use soy as an additive. So stick with whole foods instead of anything overly processed. Want some suggestions? Check out this easy infographic to find out the best whole food sources of soy protein to add to your diet.

How to incorporate soy into recipes

Vegan Crispy Tofu Poke Bowl
Vegan Celery, Kasha and Tofu Feta Salad
Zoodle Tofu Stirfry
Vegan Sriracha Grilled Tofu and Pineapple Skewers
Soy PB & Jelly Chia Pudding
PB & Banana Protein Pudding

research on the dangers of soy on breast cancer and heart health?

  1. Soy contains a compound called isoflavones, a plant estrogen, which competes with endogenous estrogen for receptors.
  2. Eating or taking a soy supplement may reduce frequency of hot flashes and vaginal dryness for menopausal women though more research is needed.
  3. Eating soy protein may potentially reduce risk of getting breast cancer and recurrence, and it is also likely safe to eat in remission -though more research is needed.
  4. 25 grams of soy protein daily can help reduce cholesterol. This Health Claim will now be found on food products in Canada.
  5. Try to get soy protein from minimally processed foods rather than ultra-processed foods and supplements

What are your thoughts on soy?
Do you like soy based products?
Is soy bad for you in your books?
Leave me a comment below – I would love to hear your thoughts!

Contribution by RD2B Maxine Seider

Abbey Sharp is a Registered Dietitian, an avid food writer and blogger, a cookbook author and the founder of Abbey’s Kitchen Inc.

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Most menopause symptoms are the result of low estrogen levels. Since the early 2000s, when health concerns caused people to stop using hormone replacement therapy, many women and their doctors have looked for alternative ways to manage symptoms. A soy diet has gained increasing attention lately as a possible treatment option, but how well does it work?

Why Soy?

Soy-based foods contain isoflavones, a type of phytoestrogen. Phytoestrogens are believed to work similarly to estrogen, and may be able to relieve menopause symptoms such as hot flashes and night sweats.

What Does the Research on Soy and Menopause Say?

In short, the research on soy and menopause is inconclusive. For seemingly every study that finds that a soy diet improves hot flashes and other symptoms, another study finds that there’s no effect. A review in The Journal of Nutrition evaluated 10 studies from the past two decades that focused on soy and its effect on vasomotor and urogenital symptoms, and found conflicting results. Likewise, a review from Virginia Tech found that some studies identified benefits of a soy diet for hot flashes and cognitive functioning, while others did not.

Researchers have noted that most studies evaluating soy have been fairly small with short durations, lasting only a few months. The University of Rochester Medical Center (URMC) finds that soy isoflavones are about one-third as effective as estrogen for reducing hot flashes, but URMC does suggest that daily soy consumption over the long term can reduce inflammatory proteins related to menopause.

What to Recommend to Patients

Given the conflicting evidence, choosing whether or not to advise patients on a menopause soy diet will likely come down to each individual. Which medications has she tried? Is she requesting a soy diet? How severe are her menopause symptoms?

Incorporating a reasonable amount of soy foods into a daily diet doesn’t pose health risks. The key is to recommend whole foods, rather than processed soy. Kaiser Permanente notes that isoflavones are short-acting, so it’s best to spread them throughout the day to get the greatest benefits.

Common sources of soy and their isoflavone content (in milligrams) include:

For example, a patient could have one cup of soy milk at breakfast, a snack of dry, roasted soybeans in the afternoon, and a side of boiled edamame at dinner.

Some people have an intolerance to soy, and too much can cause stomach pain, bloating, gas and diarrhea. Caution your patients to watch for signs of gastrointestinal distress as they add soy, and to stop if it causes them problems.

Despite conflicting evidence, there’s a real chance that for some women, a soy diet may improve menopause symptoms. Discuss the connection between soy and menopause with your patients and advise them on how they can incorporate soy-based foods into a healthy eating pattern.

Menopause and the Soy Question

As a result of their declining estrogen levels, women going through menopause often experience a range of uncomfortable symptoms — hot flashes, decreased sex drive, mood swings, increased abdominal fat, vaginal dryness, and more. Hormone replacement therapy — or HRT, the use of synthetic estrogen and sometimes progesterone to keep these symptoms at bay — was once thought to be the universal solution to this situation.

Then, the Women’s Health Initiative, a large clinical trial halted in 2002, found evidence that taking hormones after menopause appeared to increase breast cancer risk in some women. Many women immediately ceased their HRT and began looking instead to alternative strategies, including soy and other natural remedies, to relieve their menopausal symptoms.

So, just what are the benefits and risks of eating soy food or taking soy supplements? And what effect does soy have on specific menopausal symptoms? Here is an overview of the latest scientific information.

Soy and Hot Flashes

Soy products contain isoflavones, plant-based compounds with estrogen-like properties called phytoestrogens. They bind to estrogen receptors in the body and function like a weak form of the hormone. For this reason, soy-based foods and soy supplements have long been touted as natural ways to combat hot flashes, as well as other symptoms of menopause.

The evidence that this is a successful option is purely word of mouth, or anecdotal, however. “There is no new data or new studies that show that soy does much of anything for menopause symptoms,” says Nancy E. Reame, BSN, MSN, PhD, the Mary Dickey Lindsay Professor of Disease Prevention and Health Promotion at Columbia University Medical Center School of Nursing and chair of the Menopause Society Research Committee. “Plus, with hot flashes specifically, there’s a huge placebo effect: In a study of 100 women, researchers have found that half the placebo group will experience a reduction in hot flashes by as much as 50 percent.”

Indeed, most studies on the subject of soy and hot flashes have found no significant difference between the effect of a placebo and that of soy isoflavones on menopausal symptoms. Additionally, hot flashes are inextricably linked to a woman’s environment (Is it too hot?) and her mental state (Are you feeling stressed out?), and “anything with such a weak effect as soy in terms of estrogen activity is not likely to have a significant effect,” says Dr. Reame.

Doctors nonetheless recommend against taking dietary supplements with high doses (more than 100 milligrams) of soy isoflavones in them, because “there’s no FDA oversight, as there is with prescription medications,” says Reame. As for food products, the story is more complicated because they have a long history of safe use in many Asian cultures. “Different soy foods, however, contain very different doses of phytoestrogens,” she explains. “Soy milk, for example, is very low in it. You’d have to drink gallons to consume the same amount that you’ll get from a serving of tofu.”

Soy and Post-Menopausal Health Issues

In women, estrogen plays a key role in maintaining bone density and promoting heart health. These two issues become particularly important after menopause when estrogen supplies start to wane. The hope was that soy could aid in post-menopausal management of these health concerns, but studies so far have not been convincing.

In an American Heart Association science advisory from 2006, for instance, 22 randomized studies were culled for evidence of soy’s effect on heart health. The majority showed it had no significant effect on high density lipids (HDL cholesterol), or on blood pressure in subjects given 50 grams of soy protein a day. In another study published in the Journal of the American Medical Association in 2004, over 200 women, ages 60 to 75, were randomly assigned to receive either soy protein or total milk protein in powder form on a daily basis for 12 months. Cognitive function, bone mineral density, and cholesterol levels did not differ significantly between the groups after a year. More recently, a 2008 study of 237 post-menopausal women who consumed high levels of isoflavone-rich soy products for a year found no difference in bone density between the test group and the control group.

Soy and Breast Cancer

Some evidence indicates that soy, if it’s consumed from an early age as it is in many Asian countries, might be helpful in preventing breast cancer, a disease whose risk peaks between the ages of 40 and 60. Conversely, “There are also studies that show that the intake of soy products in adult years can increase the incidence of breast cancer,” says Andrea Ronning, a nutritionist at New York-Presbyterian Hospital/Allen Pavilion. This is particularly true for women who are at high risk for breast cancer — or who have had it in the past. According to the American Cancer Society, these women should avoid soy products, especially supplements, altogether.

Soy and Your General Health

While there may be no scientific evidence to support soy’s efficacy in relieving menopausal symptoms, doctors still recommend incorporating a variety of soy foods into your diet for other basic health reasons. “To counteract potential weight gain during menopause, we recommend increasing your intake of plant-based proteins like soy as a substitute for high-fat animal proteins,” says Ronning.

It appears that soy-based foods can be beneficial to post-menopausal women for many reasons. They are rich in fiber, vitamins, and minerals, and they have a high content of polyunsaturated fats, and low amounts of saturated fats.

Is soy a safe alternative to HRT?

Most women who are going through menopause will have experienced some of the annoying (or, occasionally, debilitating) side effects that come with it. These unpleasant side effects, which can include hot flushes, mood swings, and vaginal dryness, are due to low levels of oestrogen.

A common treatment prescribed for the management of menopausal symptoms is hormone replacement therapy (HRT). This is normally oestrogen alone or combined with another hormone, progestin, given in the form of patches or as tablets.

However, HRT is not suitable for everyone. Women who have a history of breast cancer, heart disease, previous blood clots, stroke, active liver disease, or high risk of endometrial cancer should not have HRT.1 This is because HRT is associated with a higher risk of causing these conditions, or making them worse. As a result, some high risk women may want to consider alternative treatments for managing their symptoms.

Why soy?

Soy contains isoflavones, which are plant-based compounds containing a weak plant oestrogen called phytoestrogen. These phytoestrogens bind to oestrogen receptors in the body and work like a weak form of oestrogen. Many people, therefore, believe that eating soy, and in doing so taking in more phytoestrogen, will provide the same effects as HRT in helping menopausal symptoms.

Everyone absorbs a variable amount of isoflavone from the same soy product, which means the effects of the soy consumed may be different in different women.

But not all soy protein contains the same amount of isoflavone. Depending on how the food is processed, soy protein can contain almost no isoflavone to a few milligrams.2 The structure of the isoflavone is also important because, in its natural form, isoflavone is attached to a sugar molecule which must be removed before it can be absorbed by the gut.

The removal of this sugar molecule is done by intestinal enzymes which vary in quantity between different people. Therefore everyone absorbs a variable amount of isoflavone from the same soy product, which means the effects of the soy consumed may be different in different women.

If you want to increase isoflavone intake it is important to check food labels to see how much isoflavone each product contains. Examples of foods that contain soy include miso soup, tofu, soy milk, and edamame.

Does soy actually help control menopause symptoms?

There haven’t been many studies done to test whether increasing consumption of soy leads to definite health benefits, and the results of the ones that have been done are generally conflicting. At present it is not entirely clear whether soy is a good alternative to HRT or not, in terms of reduction of menopause symptoms.

In one large study of 1106 premenopausal Japanese women it was found that women who consumed more soy and had a higher isoflavone intake experienced fewer hot flushes.3 But in another study of 87 menopausal women who were given one muffin a day containing soy, it was found that there was no difference in frequency or severity of hot flushes between them and women who didn’t consume extra soy.4

Women who have hot flushes and take HRT, however, seems to have improved quality of life.5 There are no studies that compare soy to HRT in how well they treat hot flushes, so we do not know which is more effective.

Some human studies suggest eating too much soy (more than 100 mg soy isoflavones a day) leads to reduced ovarian function, with lower circulating sex hormones.10 In general, diets containing 1-2 servings of soy a day are considered safe.

In another trial of 25 postmenopausal women who supplemented their diet with soy flour, linseed or red clover sprouts, it was found that there was more vaginal hormonal release with soy flour compared to the latter two foodstuffs.6 This suggests that soy may help with menopause-related vaginal dryness. However, this was a very small study, so more research needs to be done.

Is taking soy safe?

In general, soy is well tolerated in most women. Some women may experience minor stomach cramps and bloating because of the starches in the soy products, however. Studies are conflicting about the harmful effects of consuming soy in large quantities. There are animal studies that suggest excessive soy can affect fertility, embryo development, and cause early puberty.8,9

Some human studies suggest eating too much soy (more than 100 mg soy isoflavones a day) leads to reduced ovarian function, with lower circulating sex hormones.10 In general, diets containing 1-2 servings of soy a day are considered safe.

Is soy more beneficial than HRT?

As the effects of soy are variable between different people, it isn’t possible to say whether or not it is better or more effective than HRT for each individual. In general, the effects of soy are deemed weaker than those of HRT, because soy contains weaker oestrogen. Whether or not you personally find soy beneficial, there is no harm in taking it, in moderation, as part of a healthy balanced diet.

If soy does not help with your menopausal symptoms and you are able to take HRT, it may be worthwhile trying HRT. There is less evidence for soy’s benefits compared with HRT for certain menopausal symptoms, which may mean you are at a higher risk of some side effects if soy is your sole alternative to HRT.

For example, the evidence for soy’s use in preventing osteoporosis is limited, and it is still unclear whether or not it is helpful in preventing bone thinning.11 There is good evidence, however, that HRT helps reducing hip fractures,12 so a danger of substituting soy for HRT is that it could potentially leave you are higher risk of bone thinning.

If HRT is not a suitable option, there are other therapies available, and soy is not the only alternative. Lifestyle measures such as taking regular exercise, maintaining a balanced diet, cutting down on spicy foods, alcohol, and coffee, stopping smoking, and reducing stress levels may help with mood.

Vaginal lubricants or moisturisers can help with vaginal dryness, and prescription medications such as tibolone and clonidine may help with symptoms of hot flushes. Finally, antidepressants may be helpful if you are experiencing low mood and are unable to take HRT. It is worth discussing your options with your GP and they will be able to help you decide which treatment is best for you.

Featured image show two women in a kitchen pouring a pot of yoghurt or milk into a blender full of fruit. The image is cropped so you can only see their torsos.

Last updated June 2018
Next update due 2020

Are soya foods beneficial during menopause?

Read the full video transcript below

Hello and welcome to my weekly video blog. And today, on A.Vogel Talks Menopause, I’m going to be discussing the use of soya products and foods in the menopause.

Should I be adding more soya to my diet?

Now, I get asked this an awful lot. Women are emailing in saying, “Should I be adding more soya into my diet? I’ve read so much about it. Soya seems to be really good at helping with menopause symptoms. What should I do?” And we’re talking here about whole soya foods. So these would be things like soya milk, soya cheese, soya yoghurt, and your sort of textured vegetable protein packets that you can get to make up into your own dishes.

Why would I not recommend these foods?

Now, I tend not to recommend these foods. And you might well be thinking, “But why? Because we do know and research has showed that soya can be something that’s very beneficial in the menopause.” Well, the reason is that the use of soya in the menopause has basically been lost in translation.

If you look to the Far East where they have soya in their diet, you look over there and menopause symptoms seem to be very few and far between, and those women who are eating a traditional diet that includes little bits of soya tend to do very well during the menopause.

But the problem is that here in the West, they’ve looked at what’s going on in the East and they’ve gone, “Soya’s great. Let’s add it to our diet.” So we’ve got a huge number of women who are approaching the menopause. They may be in their late 30s, early 40s, suddenly starting to add lots of soya foods into their diet. And this is the problem because whole soya foods can cause a whole range of issues.

Whole soya foods, the phytoestrogens, if you like. The ingredients that we are looking for, the hormonal action that we’re looking for in soya is locked into the soya foods themselves, and whole soya foods can be very, very difficult to digest. They can cause bloating. And especially if your digestive system is not used to them and all of a sudden you start putting lots of soya foods into your diet, you can end up with bloating, you can end up with wind, you can end up with constipation.

And I’ve had people who are drinking, you know, a litre of soya milk a day and then wondering why they feel really awful all the time. And it’s purely because the majority of us here, our digestive systems can’t cope with whole soya foods.

Fermented Soya – What’s the difference?

So if you go back to the Far East, in their traditional diet, the soya foods that are eaten are things like miso, tempeh, annatto, and fermented soy sauces and other foods such as these.

Now, fermented soya is very different to whole soya foods. They’ve been fermented and, in that process, these phytoestrogens have almost been unlocked from the soya foods, so they are much more bioavailable in our digestive system, and our digestive system doesn’t have to work so hard at dealing with them.

And if you think about it, one of the big symptoms in the menopause is that our digestion can get weaker as we go through the menopause. So having soya foods that have already been partly digested, if you like, through the fermentation process can make it much easier on our digestion. And because these phytoestrogens have been partially released, we are going to get a lot more benefit from them eating less soya products.

Let your digestive system get used to it

So all I would say here is that if you want to start adding soya foods into your diet, go along to your local health food shop. They will have a range of fermented soya foods and you can start. Just do it very slowly so that your digestion will get used to it and you’ll know whether these foods are actually going to be helpful for you or not.

What about tofu

Now, the one thing that a lot of people ask is tofu. Tofu is not normally fermented. In small amounts, it’s absolutely fine. And again, this isn’t something you should be putting into your daily diet. I love tofu, especially the smooth tofu. I love it in salads and in stir fries. But I’ll maybe only have it once a fortnight or something like that and just have small amounts as well. Again, if you look at the traditional Eastern diet, they will have tofu, but it would just be part of the meal. It won’t be the major product that’s in the meal. So just take care with soya products.

Getting digestive problems?

If you have been eating a lot of soya products and you suddenly notice you’re getting digestive problems, hopefully, you will now know the reason why. There will also be those of you asking, “But you have soya in your menopause support products.” Yes, we do, and it’s fermented soya. And that’s the reason that we put fermented soya in the product, is to make sure that it’s actually going to be beneficial for you and it’s not likely to cause any particular problems.

Menopause Support

Menopause Support can be used to help you through all stages of the menopause.

Using fermented soya beans means that the important phytooestrogenic soy compounds (genistein, daidzein and glycitein) are more easily absorbed by the body.

Find out more

So I hope this has maybe given you a little bit of food for thought and, hopefully, that will help you. So I look forward to seeing you next week on another edition of A.Vogel Talks Menopause.

Ask the experts

I read that soy isoflavones help ease menopause symptoms, is this true?

Doctor’s response

Isoflavones are chemical compounds found in soy and other plants that are phytoestrogens, or plant-derived estrogens. They have a chemical structure that is similar to the estrogens naturally produced by the body, but their effectiveness as an estrogen has been estimated to be much lower than true estrogens. Two types of isoflavones, genistein and daidzein, are found in soy beans, chick peas, and lentils, and are considered to be the most potent estrogens of the phytoestrogens. Still, the estrogen potency of phytoestrogens is estimated to be only 1/1000 to 1/100,000 of that of estradiol, natural estrogen.

Some studies have shown that these compounds can help relieve the symptoms of menopause, and many women do use soy products to help control the symptoms of menopause. In particular, women who have had breast cancer and do not want to take hormone therapy (HT) with estrogen sometimes use soy products for relief of menopausal symptoms. However, some phytoestrogens can actually have anti-estrogenic properties in certain situations, and the overall risks of these preparations have not yet been determined. For example, researchers have shown that long-term use of phytoestrogens in postmenopausal women led to an increase in endometrial hyperplasia (overgrowth of the tissues lining the uterus) which can be a precursor to cancer. Further research is needed to fully characterize the safety and potential risks of phytoestrogens.

There is also a perception among many women that these products are “natural” and therefore safer than HT, but this has never been proven scientifically. If you are experiencing uncomfortable symptoms of menopause, your doctor can help you decide what type of treatment is appropriate for your individual situation.


By John R. Lee, M.D. and Virginia Hopkins

Today, it’s all but impossible to find a health-related magazine or TV show that doesn’t shout out the benefits of soy foods for the prevention of menopause symptoms, breast and other cancers, heart disease and osteoporosis. In the past decade, the soy industry has poured hundreds of millions of dollars into the research, marketing and advertising of soy foods, and it has been well rewarded for its efforts. However, while we agree that certain soy foods, eaten in moderation, can be a healthy addition to the diet, we believe that women who are eating soy with every meal, or even every day, may be damaging their health. Soy has its good side, but it also has its bad side, which has been largely ignored by those rushing to cash in on this nutritional fad.

Traditional Asian soy foods such as tofu, tempeh, and miso have been a dietary staple in that part of the world for centuries, and they are increasingly found in Western diets. Western food manufacturers have also developed a slew of new soy foods, using these little beige beans as an ingredient in protein powders, hot dogs, burgers, cheese, cereals, sports bars, and other convenience foods. Soy milk, texturized soy protein, and soy cheese have been touted as nutritious alternatives to cow’s milk products and meat. Supplement companies create pills from soy phytochemicals and advertise them as natural medicines for relief of menopause symptoms, or as protection against cancer, heart disease, or osteoporosis. Soy powders are sold as supposedly healthy meal alternatives. Some of these products are good for you, and some are best avoided. In this chapter you’ll find out how to eat soy foods so they enhance your health….


With all that we know about the pitfalls of conventional medicine’s treatment of women in menopause, it makes sense that women are turning to natural approaches to relieve menopausal discomforts. The beneficial effects of estrogen on these discomforts are indisputable, but as women become more informed they see that the risks – especially of breast cancer – may be too great to justify its use. Others stop using conventional HRT because of side effects, and look to natural remedies to help them control their menopause symptoms.

This growing interest in natural solutions for treating menopausal symptoms has prompted the food and supplement industries to develop alternatives to conventional pharmaceutical estrogens such as Premarin. The soy foods industry has been poised to benefit most from this search for natural remedies for menopause because of soy’s high phytoestrogen content.

The lay press and the soy industry have widely promoted the message that soy phytoestrogens act, in effect, as surrogate estrogens. Such a message gives women the impression that they can use soy to naturally relieve symptoms of falling estrogen levels at menopause. While the research does show that isoflavones behave like estrogens in the body the conclusion that they are all the medicine a woman needs to help her through menopause is not borne out by recent clinical studies on soy and menopausal symptoms.

Soy phytoestrogens have very little effect on vasomotor symptoms such as hot flashes, night sweats and vaginal dryness. In one comprehensive study from the Bowman Gray School of Medicine in North Carolina, researchers looked at the effects of soy phytoestrogens on women aged 45 to 55 with menopausal symptoms. This study was big news because the women who took a phytoestrogen-rich soy supplement reported a 50 percent decrease in the severity of their hot flashes. What most news stories didn’t mention, however, is that the placebo group reported a 35 percent reduction. Furthermore, this study showed small reductions in the severity of hot flashes, but none on their frequency. In other words, these women were having just as many hot flashes as they did before they added soy foods or supplements, but the intensity of those hot flashes were diminished. While decreased intensity is certainly a good thing when it comes to hot flashes, soy estrogens are clearly not as potent as many forms of conventional estrogen replacement which often eliminate hot flashes quickly and completely.

A recent study of women with vasomotor symptoms at the Mayo Clinic showed no benefits from soy protein isolates, which have high levels of phytoestrogens. This has also been Dr. Zava’s experience in analyzing saliva hormone level results accompanied by detailed questionnaires; soy phytoestrogens simply don’t work well to control vasomotor symptoms. The isoflavones in soy are aromatase inhibitors which lower the levels of estrogens made by the body, which is counter-productive to controlling vasomotor symptoms.

Soy phytoestrogens do have the estrogenic effect of stimulating the growth of breast cancer cells in tissue cultures. Several studies presented at a recent soy symposium showed that soy protein isolates stimulate the growth of normal breast cells much the way that natural estrogens do, and of course this would add to breast cancer risk if progesterone is not present.

To read more about how to eat soy so that it helps not hurts, please read Dr. Lee’s book, What Your Doctor May Not Tell You About Breast Cancer

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