Why is Soy Bad for You, and Why It’s Good Too

What is the deal with soy? People have been eating it for thousands of years, vegetarians of modern times have praised it for decades, but what’s all this about hormones and GMO’s?

Soy is one of those foods that seems to be just about everywhere. It’s a main ingredient in a significant number of processed foods at the grocery store. The majority of protein bars and powders include some version of soy. And of course there are more recognizable forms like soy sauce, tofu, and the whole bean itself (edamame). But because a food is widely used is by no means a sign of its worthiness as part of the human diet. So what’s the deal? Is it a health food wonder, or a toxic substance to avoid? Should we eat soy or not?

According to the study, “The Effects of Soy on Health Outcomes” by the Agency for HealthCare Research and Quality, after a rigorous review of thousands of studies, the conclusion was, “The dangers of soy are overstated. The benefits may be too.” In other words, the science community is stumped.

In regards to whether we should eat soy, the answer may not be as simple as we’d like, but it’s not as complicated as some may think either. Honestly, when it comes down to it, the science is so inconclusive and contradictory that it can be assumed the answer lies in the middle of the road. It’s not as bad as some would have you think, and it’s not as good as others suggest.

To tackle this topic, let’s start with a few things that we do know for certain.

#1 – Choosing Organic Soy is a Must
Roughly 80% of soy is grown using genetically modified (GM) seeds. What does that mean? These seeds have been genetically altered to show desired traits, such as drought or pest resistance for example. This is not done in traditional breeding methods, but by gene splicing where genes of unrelated species are combined.

Is it dangerous? Is it good for you? Who knows? But while no one knows, and the potential for severely disastrous health and environmental benefits is very high, these crops are grown all over the world and being tested on the human population as one big experiment. The only way to know your soy has not been altered, and to opt out of the experiment, is to purchase organic soy. Because so much of the supply has been modified, you have to assume that unless it is organic, it is a GM product.

#2 – Fermented soy is better than non-fermented soy
Who’s been eating soy longer than the traditional Asian cultures? We’d be wise to look at how they eat it, which is normally to ferment the soy beans first. Soy beans – like many beans, nuts, and seeds – have a compound called phytates which can bind to minerals in your body and have negative impact on your health. The fermentation process breaks down the soy, in essence ‘pre-digesting’ it, making it easier to digest when you eat it.

This process also adds other nutrients including probiotics, which are always a good thing. Fermented options include miso, natto, and tempeh. Tofu isn’t necessarily a fermented product but has also been used in traditional cultures for thousands of years along with the fermented forms and could generally be accepted in that list.

Now for what is still up for debate.

#1 – Soy causes breast cancer
There’s been a lot of worry generated from the hormone-mimicking compounds in soy called isoflavones, sometimes referred to as phytoestrogens. The concern is that these compounds increase estrogen levels which could then increase the likelihood for breast cancer, which is heavily influenced by hormone levels.

The studies done on this aspect have been all over the place. However, the only studies that showed an increased risk of cancer were done on mice with no ovaries or with damaged immune systems and that ate high amounts of processed soy. Other studies showed soy having no effect at all or actually reducing cancer risk. ¹

#2 – Soy can destroy your thyroid
This is another example where the studies are contradictory and most of the studies showing negative outcomes were poorly designed, often using soy levels that are so high you’d have to eat unseemly amounts of soy at every meal to see similar results. A review of studies done on this topic showed no significant effects of soy on the thyroid except in people who were iodine deficient, which is not commonly seen in our country.

Researchers in another study looked at the effects on hormones, including the thyroid hormone, at common consumption levels. This study, published in the American Journal of Clinical Nutrition, found no significant effect from soy. ²

Other common statements against soy include it being dangerous to babies, that it can interfere with digestion and mineral absorption, and even play a role in developing Alzheimer’s disease. More concrete data would be helpful, but as in the other examples, it simply doesn’t exist. Just as many studies that show a correlation show just the opposite. A study in the Journal of the American Medical Association showed no difference in the in the health of adults ranging from 20 to 34 years old who had been fed soy formula as infants. ³

In the case of soy, observing traditional cultures is very helpful, showing that when consumed appropriately, soy can be a healthy part of a traditional diet.

So with those questions, why eat soy at all? The truth is that soy, especially the fermented varieties, have a long list of nutrition and health benefits that make it worth including in your diet.

First item to note is soy’s high level of magnesium. Magnesium is responsible for a number of enzymatic processes in the body and a lack of this mineral can have detrimental effects on the body. Headaches, cramps, and stiffness are all signs that you are low in magnesium. Soy can help you increase magnesium levels naturally.

In addition, soy has been shown to have a significant positive impact on cholesterol, including one study that showed it to be just as beneficial as statin drugs. In addition, soy can help balance your blood sugar, which is crucial in preventing obesity and cardiovascular diseases.

On the positive side of hormone effects, soy can reduce abnormally high levels of testosterone, it can reduce PMS symptoms, and can balance hormone levels throughout the body’s various systems.

A Few Caveats

Being a major ingredient in the majority of heavily processed foods, soy in heavily processed forms – just like wheat and corn – can have major negative consequences on your health. Avoid highly processed versions, and in that list we include protein isolates that are the main ingredient in so many protein bars and powders as well as many of the vegetarian/vegan fake meat products. As always, say no to fake, processed “foods.”

As for soy milk, because it’s hard to find brands that don’t include oils, colors, and thickening agents that are best avoided, Kelli and I are big on making our own dairy-free milks at home. When done right soy milk can be healthy, and it’s so easy to do with little more than soybeans, water, and a blender. If you want soy milk, do yourself a favor and make your own.

To wrap it up, we’re not saying that soy is a wonderfood that you should eat for breakfast, lunch, and dinner. What we are saying is that it’s not something that you need to be afraid of or alter your eating patterns to avoid. Answering our original question, should we eat soy, a correct answer is yes, when eating the right forms. It can certainly be a healthy part of your diet. Remember, in choosing how to include soy in your diet, we are only recommending whole and traditional versions. Also consider that the vast majority of soy crops have been genetically modified (GM). Always choose organic soy.

Focus on the fermented options, experiment to find ones you like and different ways to use them, relax and have fun.

References
1 Messina, M. 2010. A brief historical overview of the past two decades of soy and isoflavone research. J Nutr. 140(7): 1350S–4S.
2 Persky, V.W., Turyk, M.E., Wang, L. et al. 2002. Effect of soy protein on endogenous hormones in postmenopausal women.Am J Clin Nutr. 75(1): 145–53.
3 Strom, B.L., Schinnar, R., Ziegler, E.E. et al. 2001. Exposure to soy-based formula in infancy and endocrinological and reproductive outcomes in young adulthood. JAMA. 286(7): 807–14.