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What’s The Deal With Soy?

What’s The Deal With Soy?

Another controversial topic in the nutrition world is soy. Science with soy can be inconclusive because with every bad study, there is a study touting the benefits of it, which is why I think people become confused. Let’s start digging!

What Are Soybeans?

Soybeans are technically legumes. This means they have very similar properties that legumes have, which are anti-nutrients like phytic acid and lectins. They also are made up of goitrogens, trypsin inhibitors, and plant estrogens. I’ll break all those down for you & how they relate to our body in a second. Soybeans do have nutrients, like B vitamins, calcium, it’s a source of protein, fiber, amino acids.

Unfortunately, almost all soy comes from genetically modified crops. They are a heavily dosed pesticide crop, which means it has lots and lots of Roundup. There are lots of ‘foods’ that are processed from soy, which is why it’s not a health food like some people think. Soy milk, soy cheese, soy protein, soybean oil, soy sauce, etc are all processed forms. Soybean oil is a very popular oil in processed foods because it’s cheap to make and use. It’s highly inflammatory because it doesn’t have the correct omega-6 to omega-3 ratio. It’s higher in omega-6, which the Standard American Diet is already high in.

Soybean oil is also extracted with a chemical called hexane. These can cause health problems and should be avoided. This is what our country eats – the processed crap. Whole, fermented sources of soybean are better to eat, still in moderation though. These are miso, natto, and tempeh. If you can find these fermented organic soy products, they are definitely okay in moderation. Soy should NOT be a staple in your diet. Now I’ll start getting into all those scientific food terms and how it relates to why processed soy is not good for you.


Plants are made of anti-nutrients. This is their protection from being ingested by animals and humans. Plants are alive, just like us. Phytic acid is what binds phosphorus in a plant and it can strip nutrients from us, so these essential nutrients aren’t absorbed that we eat in our food & we can become deficient. Phytic acid can block iron, calcium, zinc, and more. Lectins is another anti-nutrient. Lectins can become destructive to the lining of our gut by binding to the small villi on our intestines and opening the ‘doorway’ to let undigested food particles, viruses, and bacteria into our body.

This is leaky gut, which can start a horrible cycle of chronic diseases. 80% of our immune system is in our gut! (A healthy gut is a healthy human) Not only can it lead to leaky gut, but nutrient absorption fails, altered gut bacteria, etc. This is why it’s VERY IMPORTANT to properly prepare legumes by soaking, sprouting, and fermenting. Just like our ancestors used to do! When whole soy products are properly prepared, like miso, natto, and tempeh, these anti-nutrients are diminished and the body has an easier time digesting. Processed soy on the other hand do not have these benefits and are still full of active anti-nutrients.


It is also are made up of goitrogens. Goitrogens can mess with thyroid function because it inhibits absorption of iodine. Iodine is needed for the production of thyroid hormones. Thyroid problems are VERY common today. A common thyroid problem I see is hypothyroid – this can lead to slow metabolism, low energy, weight gain, and more. Not very fun stuff. This study shows that isoflavones in soy does inhibit thyroid function. Rats consuming soy in this study showed that thyroid peroxidase becomes inactive and there is a deficiency in iodine. Soy can disrupt the endocrine system.

Trypsin Inhibitors

It also has trypsin inhibitors and this can block digestion of protein. Processed soy products aren’t cooked or prepared properly, so trypsin inhibitors can still be at large. These trypsin inhibitors have also been studied to harm animals by enlarging pancreas – ultimately making them sick animals. Guess what is fed to conventional cows, chickens, farm-raised fish, etc? You guessed it. Soybean meal. Gross. Our animals are NOT meant to eat that cheap stuff. If we eat sick animals, we will become sick.

Plant Estrogens (Isoflavones)

This is one of the most talked about components! These plant estrogens can raise estrogen levels in woman, lowers testosterone levels, and simply interferes with the endocrine system, which makes our essential hormones. If a man eats lots of soy products, their testosterone levels can be lowered, which causes weight gain, low sex drive, and stamina problems. The higher estrogen levels for women can cause hormonal problems that can affect her menstrual cycle, fertility, and ‘women’ cancers like breast and ovarian. Hormones is what makes our body work. We need to eat foods that support it!

This study shows that isoflavones can act like a antagonist or agonist depending on the estrogen activity. Another study shows how isoflavones can bind to estrogen receptors and how it also stimulates MCF-7 cells. MCF-7 are a kind of breast cancer cells. Here is an extra study that shows the increase of MCF-7 while intaking soy. The American Journal of Clinical Nutrition did a study with two groups of women, one eating soy protein. The group that ate soy protein had more pre-cancerous cells in the breast. I hear woman say that their doctors recommend soy for minimizing menopause symptoms. There was a study that did help with short-term menopause symptoms, but it does not show how soy affects us in the long-term, which is what matters. The American Journal of Clinical Nutrition did another study with eating soy and the affect it had on a woman’s menstrual cycle. The higher intake of soy can lead to a period that is irregular and longer.

Other people believe that soy can prevent the risk of heart disease. The American Heart Association did a study that did not support the intake of phytoestrogens in reducing the risk for heart disease.

Because soy is so controversial and there are studies that show the dangers of soy, I recommend to stay away from processed soy.

Processed soy (well, processed anything!) has no place in our diet. It is not prepared properly and still has many harmful things still intact that leads to health problems. In general, the soy that is in the U.S. is genetically modified and heavily dosed with Roundup. Most people just want to avoid just that anyways. If you do want to have fermented organic soy (miso, tempeh, and natto), go ahead. Those are much better choices because correct preparation methods are used to reduce harmful effects from anti-nutrients, goitrogens, etc.!

Stay healthy, friends!

If you’re wondering about if wheat is okay, learn about it here!

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Lahana Vigliano

Lahana Vigliano is a Certified Clinical Nutritionist and CEO of Nuvitru Wellness. She has her Bachelor's Degree in Nutrition Science and Masters Degree in Nutrition Science and Functional Medicine. She is currently pursuing her doctorate degree in Clinical Nutrition. Lahana and her team help support women who struggle with weight loss, hormonal imbalances, digestive issues, chronic fatigue, and many other lingering issues that leaves women not feeling their best. She uses food as medicine, as well as herbs and supplements when needed, to support her clients. She looks at the whole body holistically making sure women are understanding how nutrition, sleep, stress, and their environment impact their health. Connect with her on Facebook + Instagram (@nuvitruwellness).