Soy is undoubtedly one of the most controversial foods there are. The debate over estrogens, pesticides, soybean oil, processed foods, protein, phytates, and cholesterol rages over many a health website, whether it be a reputable information source or a biased blog.
Even though soy is just one ingredient you can use in our machines, it’s important to understand the basic facts about soy.
The compounds in soy that have come under the most fire are isoflavones, or phytoestrogens. They can attach to estrogen receptors in the body. This means that they can “pretend” to be estrogens, and the body can be fooled into thinking they are a human hormone.
This may sound terrifying, and it has indeed been used to scare people away. But it’s important to look at the science under the sensationalism, and understand what this really means.
Estrogen is the main female sex hormone, so it regulates the traits that make women different from men. It’s important to note that men also have estrogen – just in smaller amounts. Similarly, women also have testosterone. Registered dietician Jack Norris points out that because of the sheer volume of studies that have been performed on soy, it’s easy to find a number of studies that point to the same conclusion, whether it be “soy causes cancer”, or “soy prevents cancer.” In Soy: What’s the Harm?, Norris states,
“The large number of studies allow people who want to make a case against soy to simply highlight a handful when the bulk of research provides a different view.”
The important point is that while some studies declare a strong correlation between soy and negative health effects, many, if not most, are inconclusive. Animal studies that dose rodents with huge amounts of anything often end up having similarly huge results. Furthermore, many studies (in both people and animals) use concentrated soybean oil or protein instead of real soy foods like tofu and soymilk. Animals are not the same as humans, and rarely will someone suddenly begin eating bucketfuls of soy protein powder. As the time-worn saying goes, moderation is key.
It also helps to observe cultures that consume large amounts of soy, not in the form of soy products in processed food, but whole soy foods like tofu, soymilk, miso, tempeh and soy sauce. Soy has been a big part of Asian cuisine for thousands of years, and (contrary to popular misconception) mostly in its unfermented form.
Data compiled by the CDC shows that in 2011, Asian/Pacific Islander women (blue line) had the second-lowest rate of breast cancer, and the lowest death rates from breast cancer.
Interestingly, a study published by Food Science And Human Wellness notes that leaving soy behind may increase the risk of breast cancer. It states,
“…there is an increasing trend of breast cancer incidence in China, partially due to the recent switch of traditional dietary styles to the “Westernized” styles”
The same study also points out that Asian people have a higher rate of digesting a certain isoflavone in soy, likely due to their longer history consuming soy. Because of that, soy may provide larger benefits to Asians than Caucasians.
Indeed, many studies among Chinese women show that soy reduced their risk for getting breast cancer, whether it be in testing for specific compounds or the rate of recurrence. The evidence is overwhelming towards the benefits of soy for this demographic.
However, a study published in the American Journal of Clinical Nutrition comparing the effects of soy on breast cancer in both Chinese and American women show that both benefitted from soy.
Regardless of ethnicity, soy undoubtedly has many health benefits. Soy provides a complete source of protein – all the amino acids the body needs to build muscle and tissue. Unlike wheat gluten, it’s other abused cousin, soy ranks a 1.0 on the PDCAAS scale, versus wheat gluten’s mere 0.25. This puts it among eggs and milk in it’s protein quality.
Soy is a great balance of complex carbs, saturated and unsaturated fats, and complete proteins. It’s also full of magnesium, phosphorus, vitamin K, and manganese.
The majority of studies on soy’s relation with cholesterol levels agree that eating soy can significantly reduce LDL “bad cholesterol” levels and triglyceride (“blood fat”) levels. A number of other studies show that replacing animal protein with soy protein significantly decreased the levels of these two compounds.
It’s easy to get caught up in the online debate, and while we may be contributing it it ourselves, it’s important to take everything with a grain of salt. It’s best to do your own research – read some studies, crunch some statistics. If that doesn’t sound like fun, we have some bottom line advice:
Feel free to eat soy, especially in its wholesome forms. Don’t go overboard with it, especially with processed protein bars or powder isolates. In fact, don’t go overboard with any one food, for that matter. If you are Asian, consider keeping up with your tofu and soymilk. Otherwise, if you aren’t used to it, or your body isn’t responding well, simply hold back. If you want to cash in on the health benefits but don’t enjoy eating it, then find another way to cook it, or just don’t.
And remember – it’s just one of the many foods that that can be part of a healthy and delicious life.
He, Fen-Jin, and Jin-Qiang Chen. “Consumption of Soybean, Soy Foods, Soy Isoflavones and Breast Cancer Incidence: Differences between Chinese Women and Women in Western Countries and Possible Mechanisms.” Food Science and Human Wellness 2.3-4 (2013): 146-61. Science Direct. Web. 2 Aug. 2015.
R.G. Ziegler, W.F. Anderson, M.H. Gail, Increasing breast cancer incidence in China: the numbers add up, J. Natl. Cancer Inst., 100 (19) (2008), pp. 1339–1341
Nechuta, S. J., B. J. Caan, W. Y. Chen, W. Lu, Z. Chen, M. L. Kwan, S. W. Flatt, Y. Zheng, W. Zheng, J. P. Pierce, and X. O. Shu. “Soy Food Intake after Diagnosis of Breast Cancer and Survival: An In-depth Analysis of Combined Evidence from Cohort Studies of US and Chinese Women.”American Journal of Clinical Nutrition 96.1 (2012): 123-32. The American Journal Of Clinical Nutrition. Web. 2 Aug. 2015.