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Soy and Breast Cancer - Is It Safe?

Like many other topics in the nutrition field, soy is surrounded by a lot of myths and has a bad reputation out there online with some groups..especially among women who have/had breast cancer. Soy (and many other other plant foods) contain “plant-estrogen” aka “phytoestrogen” which people fear mimics human estrogen and can stimulate cancer growth due to the chemical structure that looks similar to the estrogen found in a woman’s body. It is thought that higher levels of estrogen in a woman’s body is linked to an increased risk of breast cancer. And that refers to human estrogens for those affected...not plant or phytoestrogens from soy or other foods and that’s what we’re going to explore today!


I am here to tell you that the phytoestrogens present in soy are not the same as the female hormone estrogen that we produce. Soy contains its own special plant estrogens that do not increase your risk of developing breast cancer. In fact, soy has numerous health benefits that actually decrease our risk of developing breast cancer. With this being said, soy should definitely be included as part of any healthy dietary eating pattern. The idea of soy not being safe is outdated, and you should keep reading below to finally clear up all the myths surrounding this superfood. I’m so thrilled to be here talking about this incredibly important subject today - let’s bust some soy myths!





Is Soy Safe?


People tell me all the time “well, I don’t eat soy because it’s not good for you.” And then I ask in what way. And then they tell me that they heard it somewhere or read it online. If they’re open to it, I ask if I can give them some information about where these misconceptions come from and how I can help them better understand this important food. A lot of people do want to eat soy and enjoy tofu, tempeh, miso and edamame but are avoiding it out of feat. I’m excited to talk about the safety today based on current research out there.


Women who have estrogen-receptor positive breast cancer are among those who are most worried about the effects soy could potentially have on their cancer treatment. Women with this type of cancer are concerned over the fact that the phytoestrogens present in soy products may actually bind to our estrogen receptors within our own cells and stimulate cancer growth. According to the Dana-Farber Cancer Institute, the phytoestrogens present in soy products do not actually turn into estrogen that could successfully bind to our own estrogen receptors. These phytoestrogens are structurally different and significantly weaker than the estrogen we produce. This is fantastic news and goes a long way in clearing up soy’s bad reputation. This also means that soy even eaten in moderate amounts does not actually increase one’s risk of further cancer growth!


The American Cancer Society recommends the addition of soy into the diet as the isoflavones present in soy may actually work to block the natural estrogen we produce lowering the risk of cancer development. This research among other current research supports the notion to include soy products and foods into the diets of both those with estrogen-receptor positive breast cancer and breast cancer survivors.


The Susan G Komen Cancer Research Center also supports including soy in the diets of breast cancer survivors. In their analysis of research, they found that women who were eating at least 10mg of soy in their diets each day after a diagnosis of breast cancer had a 25% lower risk of the cancer returning compared to other women only consuming 4mg of soy or less. The Komen center states that eating moderate amounts of soy each day is part of an overall healthy eating pattern as turning to more plant-based sources of protein is a great way to maintain your health status and weight control which is a key factor in breast cancer risk. The truth is that soy products are completely safe and should be included in everyone’s diet due to their amazing health benefits!


Health Benefits of Soy


Soy products are a popular alternative to meat and for good reason. Foods including tofu, tempeh, edamame, miso, soybeans, nuts/oils, meat alternatives, and soy milks are all examples of ways to enjoy this group. Soy is an excellent source of protein because it is a complete protein meaning that it contains all 9 essential amino acids typically found in meat products. This is great news for any vegetarians or vegans who are worried about not getting enough protein. Please note that most vegetarians and vegans have no problem meeting their protein needs...especially if they eat beans and soy.


Additionally, soy is packed full with micronutrients including potassium, magnesium, and even fiber! Fiber is hugely important for its role in regulating bowel movements, helping you to feel fuller, and provide long-term satiety. Many soy products are fortified with even more nutrients like B-vitamins, calcium, and Vitamin D to ensure that all nutrient needs are being met. Not only is soy a superfood, but it also helps in lowering cardiovascular disease risk factors.


The macro and micronutrient composition of soy is remarkable. The obvious high quality of protein makes it nearly identical to that of meat, and it is also low in carbohydrates which makes it a perfect option for those who want to eat that way. Soy also contains essential fatty acids like omega 3’s which work to decrease inflammation within the body. Additionally, soy has been directly linked to heart health including assisting to lower LDL/bad cholesterol and even helping to lower blood pressure, reduce arterial stiffness, and promote vasodilation or blood pressure relaxation. Eating soy products may reduce rates of cardiovascular events, like heart attacks! This may be due to the fact that soy can help in decreasing your intake of saturated fats which are a leading cause of heart health issues. Substituting soy in place of animal proteins a few times per week is a great way to cut out those extra saturated fats and reduce your overall risk of heart disease.


How to Include Soy in your Diet


Incorporating soy into your diet can be challenging especially if you have never eaten or cooked this food before. As always, it is best to stick to a food first approach and consume your soy from food products rather than supplements as the research on supplementing with soy isoflavones is unclear. To slowly start incorporating soy into your diet you might consider 1-2 servings each day. A single serving of soy includes drinking 1 cup of soy milk, eating ½ cup of edamame, or ¼ cup of tofu.


If you are looking for more recipes on soy then look no further! I have tons of recipes on soy that will elevate your taste palate and introduce you to a wide variety of flavor profiles. Consider trying any of these recipes:


And for even more recipes and ideas check out my post on the 50 Best Plant-Based Recipes.


Soy and Your Lifestyle


Soy is one of the most widely researched foods in the world! There is a massive amount of research surrounding this superfood which means all of the bad reputation and myths circulating on the internet is completely uncalled for. Soy products are entirely safe to consume for those currently fighting breast cancer or who are breast cancer survivors. Soy is truly a superfood with amazing health benefits including lowering cardiovascular disease risk factors, it is a complete source of protein, and is high in fiber and micronutrients while still being low in saturated fat and cholesterol.


I cannot say enough about the powerful effects soy can have on your lifestyle. If soy is not something you have tried before then start slowly and gradually increase it in your current meal plan. I provided numerous links to amazing recipes that will help you navigate this food and all the endless flavor combinations. Soy is safe and can be included many times throughout the week to elevate anyone’s current dietary eating patterns to include a healthy and versatile ingredient!



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