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Is Soy Healthy? Can You Eat It If You Have Cancer?

​Is soy healthy or a health hazard? Discover which soy products you can eat if you have cancer. And also learn why you should avoid GMO soy and fake foods.


Legal Notice

The information is presented for educational purposes only and is not intended to diagnose, prescribe treat or cure cancer.This information is not intended as medical advice, please refer to a qualified healthcare professional.

​What Is Soy?

Soybeans originated in Southeast Asia. Chinese farmers domesticated them around 1100 BC. By the first century AD, soybeans spread to Japan and many other countries. It wasn’t until the 1940’s that soybean farming took off in America.

Soy is a vital part of the global food supply. We use most of it as animal feed. Soy has become one of the world’s biggest crops due to our desire for meat products. Around 75% of soy worldwide is livestock feed.

Soy farming

​Around 75% of soy worldwide is livestock feed

We classify soybeans as legumes, a group of plants whose seeds grow in enclosed pods, like peas or peanuts. The nutritional profile of soy is much different than most beans. Soybeans contain a lot of protein and fat and fewer carbohydrates.

In Asian countries, they eat soy from miso, tofu, soy sauce and more. Less than 5% of daily calories in the typical Japanese or Chinese diet comes from soybeans.

There are various soy products on the market, some of them are:

​Different Soy Products On The Market

Edamame: Edamame is a small, furry, dark green pod that has a mild flavor.

​Kecap Manis: Kecap is a type of thick, sweet soy sauce used in Malaysian and Indonesian cooking. It consists of dark soy sauce, palm sugar, star anise, and garlic.

Miso: Miso is a combination of soybeans and a grain such as rice or barley. It goes through a fermentation process with salt, and sometimes a unique mold. Miso has different colors such as white, yellow, red, and brown. You can find it in soups or seasonings.

Natto: Nato is a fermented soy food. You produce it by adding the bacterium Bacillus natto to steamed soybeans. After fermenting it for 15 to 24 hours, the soybeans develop a brown color. Natto requires no extra cooking. You can serve it as a topping for rice or noodles, or add it to miso soups, or salads.

Soybean sprouts: Soybean sprouts are soybeans that you sprout.

Soy cheese: Soy cheese can be both firm and soft. Soft soy cheese is an alternative to sour cream or cream cheese. Firm soy cheese looks like dairy cheeses, such as mozzarella or cheddar. Some brands of soy cheese may also contain dairy proteins. Like regular cheese, soy cheese can be high in sodium and fat.

Soy flour: Soy flour is roasted soybeans that you ground into a fine powder. It is a rich source of protein, isoflavones, folate, iron, and magnesium. Soy flour contains almost three times more protein than wheat flour. You can use it as a thickener in sauces or gravies.

Soy grits and soy flakes: Soy grits are toasted, cracked soybeans that look like coarse cornmeal. Soy flakes are dry-roasted whole soybeans that are often cooked and served as a hot cereal.

Soymilk: Soymilk is the liquid filtered from soybeans that you soak and then strain. It is often substituted for cow’s milk by people who have food allergies or who are lactose intolerant. Soymilk is often a milk replacement for vegans.

Soy sauce: Soy sauce is a dark brown, salty condiment that is popular throughout the world. You make this sauce by first fermenting soybeans and mixing it with roasted grains. The grain is often wheat, barley, or rice. This mixture is then injected with a special yeast, and flavored with salt.

Soynut butter: Soynut butter is roasted whole soybeans that you make to a spreadable form.

Soy protein isolate: Soy protein isolate comes from defatted soy flakes. It contains about 92% protein. You can find it in protein powders and fake soy meats.

Soy yogurt: Soy yogurt comes from soymilk. This product has the texture and consistency of dairy yogurt. Soy yogurt is available in different flavors, with and without active cultures.

Tempeh: This soyfood is a useful meat substitute and originated in Indonesia. Manufactures make it by culturing and fermenting soybeans into a cake form. Tempeh contains more protein than tofu and is a bit more flavorful.

Tofu: Tofu is a creamy white soy product sold in small blocks. You make it by coagulating the protein of soybeans in the same way you produce cheese. Tofu can be stir-fried, broiled, grilled, sautéed, or baked. There are two basic types of tofu, silken and regular.

Yuba: Yuba is the thin layer formed on the surface of heated soymilk once it has cooled.

​Soy oil: Soy oil is the fat extracted from soybeans.

​Chinese people have eaten soy for at least 1500 years and ​the Japanese for 1000 years. Both unfermented and fermented soy continue to be a big part of traditional Asian diets.

Soy is a controversial food. It has been well established that estrogen makes cancer more aggressive.

Soy has a component called phytoestrogen that mimics estrogen. Therefore many experts believe that soy causes more cancer. ​

​So is soy healthy? ​Can it cause cancer?

​Is Soy Healthy​ If You Have Cancer?

Many reports warn about phytoestrogens in soy products. This chemical looks like estrogen. Because estrogen fuels many breast cancers, soy has long been a source of concern. People worry that it might raise their risk of hormone-related cancers.

But these initial reports where false. Even if soy contains phytoestrogen which looks like estrogen, it doesn't behave like it. Soy is not a hormonal food. The phytonutrients in soy may protect against cancer.

Phytoestrogens are 1000 times less potent than estrogens. They cannot turn on the same cells that estrogen can. Because of that, they can block cell receptor sites.

cancer cells treated with soy

​Cancer cells treated with ​soy

Scientists have not found that diets high in soy increase our breast cancer risk. All long-term human studies of soy show that it has a protective effect against cancer. There have never been any direct correlations between soy and cancer.

Breast cancer survivors who eat soy foods have a lower risk of cancer recurrence. Some researchers tested phytonutrients on cancer cells. The soy repaired the DNA and turned on tumor-suppressor genes BRCA1 and BRCA2.

So we have now established that soy from whole foods doesn't cause more cancer. But there are some ways that soy can worsen our cancer.

​​Fake Soy ​Products Are A Health Hazard

Soy from whole foods prevents cancer. Some people, therefore, believe that all soy products have anti-cancer properties. However, there is also a dark side to soy. Like other foods soy become unhealthy when you process it.

All highly processed foods whether plant-based or otherwise increase our health risks. As we transition to a vegan diet, we sometimes think that avoiding animal products is enough. The label vegan often lures us into the convenience trap.  

Over the past two decades, there has been an explosion of fake soy products. New vegans often get fooled into consuming artificial soy products. We can buy various soy foods that resemble our favorite meat and dairy products.

dish meat fake soy meat

​Soy meats contain soy protein isolate, ​picture by Maksym Kozlenko 

Manufacturing processes remove the dietary fibers, carbohydrates, fats, vitamins, and minerals from the soy. The whole process leaves behind almost pure soy protein. We call this product soy protein isolate. Soy protein isolate contains about 92% protein.

It replaces dairy protein in candy bars, yogurt, ice cream, bread, and cookies. Our modern technology turns these mixtures into products that look and taste like meat. These new fake foods in no way resemble nature’s creations.

Phytochemicals found in plants are essential ingredients for radiant health. But you must get it from traditional soy foods to reap the most benefits. Processed soy products like soy nuggets, burgers, and sausages are not healthy.

One thing ​in soy protein isolate that increases our cancer risk is IGF-1.

​IGF-1 In Soy Protein Isolate Can Feed Cancer

IGF-1 is a growth hormone that makes cancer more aggressive. Plants contain little IGF-1, and animal products have lots of it. When you isolate one component and concentrate it, you make a health food a health hazard.

protein shake

​Soy protein isolate in protein powders raise our IGF-1 levels, picture by Sandstein

Soy protein isolate raises our IGF-1 levels and feeds our cancer cells. You can find soy protein isolate in many processed junk foods like soy meats. Also look out for it in baby instant formulas. They usually contain soy protein isolate, canola oil, sugar, and other junk.

Avoid processed forms of soy, including supplements and fake meats. Instead, choose whole forms of soy, like organic edamame, soy nuts, miso, tempeh, and tofu.

Another soy product you should avoid is soy oil.

Soy Oil Is Unhealthy Too

Soybean oil is a vegetable oil extracted from the fat of the soybean. It is one of the most used cooking oils on the market. There are two methods of producing soybean oil.

One approach is mechanical. The producer squeezes oil out from seeds and kernels without cooking the seeds. Another way to extract soy oil is to heat the beans. This method yields more results than the mechanical process.

To produce the oil, the manufacturer heats the beans to between 60 and 88 ºC (140–190 °F). They then use hexanes and other processes to create the oil.

soy oil

​Soy oils contain 100% fat, picture by United Soybean Board

Vegetable oils are not healthy. It doesn't matter if they are cold-pressed or hydrogenated. Soy oil is a highly processed product that is detrimental to our health. As with soy protein isolate you extract one component and concentrate it.

Oils contain 100% fat and nothing else from the plant. If you want to be healthy, then you need to eat a whole food plant-based diet with no added oil.

Oils are as unhealthy as white sugar. So why does everyone say that sugar is unhealthy? It's because you separate all the nutrients from the sugar beet and make a white powder that is 100% carbs. There are no nutrients or fibers from the plant.

It's the same way with oils. When you make oils you strip out all the nutrients from the plant and create a product that is 100% fat. 1 cup of soy oil contains about 1962 calories. Oils may cause weight gain, even so-called "healthy oils," like olive oil.

We don't need oils to be healthy. It's better to get our fat from whole foods instead of highly processed foods.

Another thing you should look out for when it comes to soy is GMOs.

90% Of The Soy Grown In USA ​Are GMOs ​​

Genetically modified organisms or GMO is another health hazard. They are creations of biotech companies like Monsanto. Over 90% of the soy processed in the USA are GMOs. Animals eat most of this soy.  

Not a single human clinical trial on GMOs exist. The FDA says that GMOs are harmless. They deemed them safe based on basic nutrition or taste, sight, smell, and touch.

GMO crops

GMOs may cause health problems and environmental damages

GMO soy contains two new proteins with allergenic properties. It also has up to seven times more trypsin inhibitors, a known soy allergen. Skin prick tests show some people react to GMO, but not to non-GMO soy.

GMO plants, have foreign genes forced into their DNA. The inserted genes come from species, such as bacteria and viruses. Biotech companies like Monsanto can even patent their ​seeds.

Monsanto Can Patent GMOs

According to US law, you can't patent plants, but you can patent GMOs.You are likely eating GMO foods every day, without knowing it. In the US, producers don't have to disclose if their products contain GMOs.

​If Monsanto can patent GMOs, then that must mean that the plants changed a lot. That doesn't sound safe to me. So long as we don't know the safety of GMOs, we should not put them in our mouths.

Monsanto protest

GMOs kill us and independent farming

The only sure way to tell if the soy is GMO-free is by buying organic soy. In Europe however, they already label GMO foods.

Monsanto has a long history of malpractice and shady business. Why should we trust them when they have shown to do evil things before?

One controversial product they created was their cancer causing herbicide Roundup.

Monsanto's Herbicide Roundup May Cause Cancer

Monsanto's GMOs can withstand their toxic herbicide Roundup. Roundup contains a toxin called glyphosate which ​breaks down into formaldehyde. ​​Formaldehyde is a known class 1 carcinogen. Meaning it’s likely to cause cancer.

On August 10, 2018, Monsanto lost a legal case to Dewayne Johnson. Dewayne sued the company for causing his skin cancer.


​Roundup contains a toxin called glyphosate which can cause more cancer, picture by Mike Mozart

Johnson used Roundup and a similar product, Ranger Pro, at his job as a school district groundskeeper. The jury awarded him with $289 million in damages.

Like many plant-based foods, soy can be a healthy part of a nutritious diet, even for cancer survivors. If you choose to eat soy, make sure they're not GMOs.

Choose organic ​soy instead. Also, avoid isolated soy protein and other processed soy, and you should be fine.


​Soybeans originated in Southeast Asia.

Phytoestrogens in unprocessed soy does not cause cancer.

Processed soy products ​that contain soy protein isolate ​can increase our cancer risk. 

Soy oils contain 100% fat and ​are unhealthy.

Genetically modified ​soy is ​ahealth hazard.

Roundup contains a toxin called glyphosate which can cause more cancer.

​How To Eat Soy Without Increasing Cancer

​1. Eat ​unprocessed soy

​2. ​Avoid soy protein isolate

​3. ​Don't use soy oil

​4. ​Buy organic soy

Action Steps

​A low-fat, whole-plant food diet, is the way to a healthier life. Soybeans are high in fat and protein. You should, therefore, see them as treats and not a staple. Like nuts, seeds, avocados, and olives you should only eat them on special occasions.

Soy, like all high-protein foods, can be a little hard to digest. Fermented forms of soy like tempeh, miso or natto are the easiest to ingest. ​Tofu is fine, too. Marinating it may help to break down the proteins and make more nutrients available. ​

​Don't overeat soy products that contain too much salt like soy sauce and ​miso.

​Avoid eating soy protein isolate found in fake meats and protein powders. Don't use soy oil in your cooking or GMOs. Buy organic soy to avoid toxic GMOs and herbicides.

You don't need to eat soy to be healthy. There are other plants and starchy vegetables that contain all the nutrients and protein that you need.

Join our 12-day vegan cancer challenge to learn how to eat a healthy anti-cancer diet. Discover what to eat if you have cancer and what to avoid. As a bonus for joining this challenge you also receive a free recipe book.

​>>Click here to join this challenge.<<

​Resource & Citations:

About the Author Simon Persson

Simon Persson is a holistic cancer blogger with a passion for natural health cures. When he is not blogging, he enjoys nature, cooking and learning about the latest gadgets on the market.


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