What New Vegans Ought to Know About Soy

If the soy controversy is driving you crazy, you’re not alone.

I have been going through a rather annoying cycle of eating it, then panicking and deciding not to eat it. A few weeks ago, I decided to put an end to the madness by reading as much as I could about soy. I studied peer-reviewed journal articles, medical and organic farming websites, and textbooks.

I have now come to my own conclusion about it. But, before I tell you where I stand, I want to share everything I learned about soy to help you make your own decision.

Let’s go back to basics…

Soy is available in many forms these days. You can eat it as a whole bean, a roasted nut, or in the form of  tofu. You can drink its milk, have it as a yogurt or as a cheese. Asians typically ferment it to make tempeh or miso.

Some manufacturers isolate soy proteins to make products like isolated soy protein (ISP), soy protein concentrate, and soy flour. These ingredients are typically found in highly processed foods such as body building protein powders, vegan protein powder blends, meal replacement bars and shakes, and in some ‘healthy’ snack bars.

Each of those isolated soy proteins can be processed even further to make texturized soy protein or texturized vegetable protein, which are typically found in meat replacement products.

Its nutritional value

The main reason you eat soy is probably because it is promoted as a health food. Indeed, when you study its nutritional composition, you will find that it is rich in high-quality protein. Its protein is of high quality because it provides all of the nine essential amino acids you need to thrive.

Soy is a good source of omega-6 fatty acids, specifically linoleic acid, and a good source of linolenic acid, an omega-3 fatty acid.

It provides most of the B-vitamins, which your body needs to convert glucose into energy. It also provides antioxidants that mop up dangerous oxygen compounds (aka free radicals) in your body.

Soy is a good source of minerals including potassium, calcium, magnesium and iron. It also contains a range of other compounds including;

  • Isoflavones
  • Phytosterols
  • Saponins
  • Ferritins

These compounds, especially the isoflavones account for a large part of the health benefits associated with eating soy.

Health benefits with scientific evidence


If your cholesterol levels are abnormally high, there is evidence to suggest that you can lower it by eating ≥25g of soy protein daily.

The backing for this recommendation comes from the results of a year long clinical study done in 2006. The study showed that individuals who ate a diet rich in soy lowered their cholesterol levels by 29.7%. Several other studies have supported this finding.

Although scientists don’t completely understand how soy protein lowers cholesterol levels, they know that the fibre, phytosterols and in particular, the isoflavones they contain play a significant role.

Soy isoflavones need to be present within the protein in order for you to experience its maximum cholesterol-lowering effects.

Unprocessed forms of soy naturally contain these isoflavones. However, processed varieties such as isolated soy protein, textured soy proteins etc do not always contain them.

Why you ask?

Because manufacturer’s extract soy proteins by washing them either with ethanol or with water. Ethanol-washing destroys isoflavones, while water-washing preserves them.

Bear in mind that you may never know which method a particular manufacturer uses to isolate the proteins unless you ask them.


Soybeans apparently contain many compounds that help to prevent cancer cells from growing. Although most of its anti-cancer properties are attributed to its isoflavones, other anti-cancer compounds are being identified.

Breast cancer

You may be able to reduce your risk of developing breast cancer if you eat soybeans regularly. However, this finding only holds true if you’re of Asian descent. Soy doesn’t have an effect on your breast cancer risk if you’re Western.

A study in 2011 showed that soy does not increase your risk of a relapse if you’re a breast cancer survivor.

However, another study in the same year showed that soy may increase the growth of cancer cells in women with early stage breast cancer. One thing to note is that the women in this study were fed soy protein protein powder.

Firstly, soy protein powder is a highly processed food, which may or may not contain the beneficial isoflavones as I mentioned earlier. Secondly soybean processors sometimes use hexane, a known neurotoxin, as a solvent for extracting its oil and its protein.

It is possible that the increased growth of cancer cells in those patients could be due to the hexane rather than the soy itself.

The hexane processing is not just specific to soybeans, it is also used to extract oils from corn, canola, cotton seed, safflower seeds, sunflower seeds and other oil seeds. If you cook with vegetable oils, your oils may also be contaminated with it.

Prostate cancer

Prostate cancer is the second most common cancer in men.

In Asian populations where soybeans are a regular component of the diet, the rates of prostate cancer are very low. In fact, Asian men seem to have a 50% lower risk of developing prostate cancer than Western men.

A compound in soybeans ‘Genistein’ is mainly responsible for this protective effect. Non-fermented foods, especially tofu provide the most protection against prostate cancer.


Hot flashes are a common symptom among menopausal women.  Since soy isoflavones can weakly mimic the effect of oestrogens in your body, many researchers have studied their impact on hot flashes.

Some studies have been unable to show a clear benefit of eating soy, but a key study in 2012 showed that soy can alleviate hot flashes.


Your risk of developing weaker bones and joints increase as you age regardless of your ethnicity. If you’re going through menopause,  you have a higher risk of developing fractures because your oestrogen levels are very low.

Your lower levels of oestrogen causes your bones to breakdown. It also  leads to the loss of calcium. If you do nothing about it, your bones will progressively become weak and brittle, with tiny holes inside of them. This condition is known as osteoporosis.

Studies done in Chinese populations show that women who eat a lot of soy have a 33% lower risk of developing fractures than women who don’t. Other studies additionally show that women who take soy isoflavone extracts maintain the integrity of their bones.


If you have type 2 diabetes, your chances of developing high blood pressure, atherosclerosis and high cholesterol levels are high. You also have a higher risk of developing kidney disease, due to excessive loss of protein through your urine.

By eating soy protein, you can reduce the amount of protein you lose through your urine and thereby reduce your risk of developing kidney disease.

Preliminary evidence suggest that soy may be valuable for treating inflammation, depression, and fertility. But there are more studies negating these findings than supporting them so I’ve left them out.

What is all the fuss about?

How can soy have so many health benefits, but still be bad for you? Well…

You may have heard the notion that men who eat soybeans develop breasts and have lower testosterone levels. This has been discounted by lot of recent studies, which show that soy proteins or their isoflavones have no adverse effect on sexual hormones in men.

Soy is also purported to affect the thyroid….

If you have not been diagnosed with a thyroid condition, and otherwise have a healthy thyroid, eating soy should not affect your thyroid. However, if you suffer with hypothyroidism and take medication for it, soy can prevent your body from absorbing sufficient amounts of  your thyroid medication.

Soy can also interfere with the functioning of your thyroid if you have undiagnosed hypothyroidism and/or if you don’t eat enough iodine in your diet.

There’s also not much evidence to suggest that soy increases your risk of endometrial cancer.

This is what should really concern you

The key problem with soy is that most of it is genetically modified. Apparently up to 95% of the soy available in the US is genetically modified. The UK currently has a ban on companies growing GMO crops, but GMO crops can be imported into the country. Very unfortunate…

If you’re wondering what is wrong with GMO soy, it may be best to understand why GMO crops were made in the first place…

Scientists initially started modifying soybeans to meet consumer demand and to solve the problems associated with its growing process. As technology advanced, they began to modify them to contain genes that could improve their nutrient content and therapeutic benefits.

Monsanto was the first company to make GMO soybeans. Their beans are specifically resistant to a certain group of herbicides called glyphosate (commercially known as Roundup). These soybeans can withstand exceptionally high levels of glyphosates without being killed, but the weed around them is destroyed.

Monsanto’s soybeans were commercially approved in the United States in 1996, and they are now eaten in various countries including, Canada, Japan, Argentina, Uruguay, Mexico, Brazil and South Africa.

The problem with GMO crops…

Glyphosate were once thought to be non-toxic to humans, but new studies are suggesting that they may be a key cause of the obesity epidemic, autism epidemic and several other diseases and conditions present in society today.

Glyphosates can increase the growth of bad bacteria in your gut, and thereby reduce the amount of beneficial bacteria. These bad bacteria can destroy the lining of your gut, allowing substances leak into your bloodstream.

In effect causing, leaky gut syndrome.

Bad bacteria can increase the production of cancer-causing compounds that negatively affect your nervous system, cardiovascular system, lungs, kidney and liver.

If you are intolerant to wheat, but you still experience bloating and other symptoms associated with gluten intolerance, it could be because you have an overgrowth of bad bacteria. You may want to check your diet to make sure that you are not eating products that are contaminated with glyphosates.

If you have non-vegan friends who struggle with IBS/celiac disease despite eating gluten-free diets, tell them to choose only organic produce. A lot of non-organically grown animals are given GMO feed, and just like in humans, glyphosates disrupt their gut bacteria balance.

Pigs fed GMO corn and maize develop severe stomach inflammation, while poultry animals develop higher levels of bad bacteria than good bacteria. This in turn affects the quality of their meat.

Glyphosates also play a crucial role in birth defects, kidney disease, anaemia, liver disease and respiratory distress.

According to Dr Mercola, GMO soy is predominantly used to make soy protein powders and soy flour. It is also used to make textured vegetable and soy proteins. They are also included in processed products under the following names:

  • Soy lecithin
  • Soya, soja or Yuba
  • Mono-diglyceride

Will I continue to eat soy?


I’ve thought long and hard about this one, and I’ve decided to err on the side of caution.

In as much as I would like to avoid soy completely, I know it is unnecessary. I also know that I will be depriving myself from an easy source of quality protein.

My decision right now is to keep eating whole soy, but only the organic, non-GMO versions. From my research, the problem with soy is not with the crop itself, but with the way it is grown and the ways it is processed to form other products.

I will continue to eat organic tofu and soy yoghurt, when I feel like eating them. Almond milk tastes so much better than soy milk to me now so I have stopped drinking it, and it is essentially no longer in my diet.

I’m yet to try tempeh, but if/when I do, I will make sure it is organic.

I will no longer eat any form of soy product in restaurants/cafe’s etc, unless there’s a  guarantee that the soy is non-GMO and organic. I say that, but being the skeptic I am, I bet I won’t eat it anyway.

I’ve already removed processed foods from my diet, but this research has given me more incentive to stick with my decision. You’d be surprised at the number of every day products that contain soya lecithin or isolated soy protein.

It is pretty shocking!

Over to you…

Now that you know my decision, will you continue to eat soy? If you’ve already stopped eating soy, what rocked the boat for you?



  1. Lauryn
    25th June 2017 / 10:13 AM

    Hey Somi, thanks again for another informative article. Which brand of tofu do you eat?


    • 25th June 2017 / 5:28 PM

      Hey Lauryn

      Thanks so much for reading :)!

      I eat the Cauldron brand of tofu.

  2. Nikki
    9th July 2017 / 2:01 AM

    What about the destruction of rainforests in order to produce soy? That is a far bigger issue for humanity and the Earth than GMO.

    • 12th March 2018 / 6:03 AM

      70% of soy is used for animal crops. 6% for human food. The rest for soybean oil.

      • 12th March 2018 / 1:55 PM

        Thank you for that insight 🙂

  3. Lisa
    9th July 2017 / 8:10 PM

    Hi Somi, thanks for this info; very interesting. I drink soy milk every day and have done so for years (I have it in chai in the mornings and sometimes make a lassi with it on an evening as well!). And I eat tofu. I buy organic, non-GMO versions of the soy milk and the tofu–and having read your article, I’m glad I do.

    • 12th July 2017 / 9:33 AM

      Organic and non-GMO is definitely the way to go! It’s awesome you’ve been doing that already 🙂

      Somi, x

  4. 11th March 2018 / 10:42 PM

    Thanks, I am pretty shocked with this article.
    have always bought organic TOFU or organic Soy milk. Is it safe to give my kids soy milk to drink every day?
    Organic, of course. But sometimes I have eaten soy Silk yogurt…. I guess it is better to skip this, right?
    Thanks again, it is really useful

    • 12th March 2018 / 1:53 PM

      Hello Olga,

      It’s difficult for me to say what you should or shouldn’t do. According to Dr Greger of nutrition facts, 3-4 servings of soy a day is fine to stay on the safe side. If you think you’re having way more than that amount, you could consider swapping your soy milk with another nut milk just to stay on the safe side.

      I hope that helps 🙂

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