Confused about soy? You’re not alone! There are a lot of opinions out there about soy, why you should eat it or why you shouldn’t, but we are curious what science says about consuming soy. While a very large majority of doctors, nutritionists, and researchers are proponents of including soy in the diet, there is certainly some controversy about the consumption of soy in the diet, as well. Does soy increase your risk of cancer? Does soy create feminine characteristics in men? Is soy dangerous? Why is soy controversial? What are the main food sources of soy? Questions like these, and more, we’ll go into the scientific facts without the fiction or opinion, to discover the shocking truth about soy, according to science.
Modern History of Soy
Soybeans – a powerful little bean that has numerous benefits and controversial claims. Soy is derived from soybeans, a tiny legume believed to have developed about 3,000 years ago in Manchuria, the northeast part of China.
- 1904, American chemist George Washington Carver discovered that soybeans are a valuable source of protein, oil, and that soybeans can even improve the quality of soil because of their ability to absorb nitrogen in the atmosphere.
- 1919 William Morse co-founded the American Soybean Association – at the time there were only 20 proven varieties of soybeans and by 1929 more than 10,000 soybean varieties had been discovered in the wild.
- 1935 Henry Ford provided scientists with soybeans asking them to create plastic-like functionalities for cars with them and the scientists did! By 1935 Ford was using one bushel of soybeans for every car he manufactured.
- 1940s soybean farming took off. The supply of soybeans from China was halted due to WWII and internal revolution. Soybeans at the time were heavily being used as oils, lubricants, plastics and other products, instead of food. US farmers stepped up to the planting and harvesting challenge, leading to a great prosperity.
- 1950s, by the end of WWII livestock farmers, due to the increased demand of meat, turned to soybeans as a food source (it’s a complete source of protein) for their livestock.
- 1990s was when improvements began coming to the soybean in the lab in order to withstand herbicides (control weeds w/o killing the plant).
- 2013 nearly 76 million acres of soybeans were planted with more than 3.2 billion bushels of soybeans harvested. Western diets don’t necessarily consume much soy as compared to Eastern diets. With that being said, just over 70 percent of the soybeans grown in the US are used for animal feed (poultry being number one). About 15 percent of US grown soybeans are used for human food consumption. About 5 percent of the US soybean market is for biodiesel (1)
The Main Food Sources of Soy
Soy can be found in a variety of foods consumed around the world and you may find yourself asking “what is soy!?”. Well for starters, if you haven’t figured it out yet, soy is the protein that comes from soybeans. Edamame, or fresh soybeans, literally means “beans on a branch” in Japanese. Inside the little pods are beans harvested to be eaten raw or made into other forms of soy foods.
In eastern cultures, the Japanese, Chinese and Indonesians (among other groups) habitually consume soy-containing foods in their diet. In the West, only a minority of people have incorporated soy regularly into their diets. Typically speaking, those who consume large amounts of soy should be very conscientious of the types and quality of the soy that they are consuming.
- Edamame (Fresh Soybeans)
- Soy Sauce
- Soy Milk
- Roasted Soybeans
Why is Soy in Everything?
You may be surprised to know that soy is included in a lot of food products, including supplements. So why is soy in so many products? Soybeans are versatile and can be used as food for humans, feed for animals, and other goods and products consumed around the world.
Modern day use of soy includes the following:
Soy-based rubber (used in cars such as floor mats, shifters, cup holders, etc.)
Food (complete source of protein, healthful nutrient profile)
Fat Emulsification (digestion)
Bind Water (keeps moistness of products without affecting other ingredients – i.e. soy lecithin)
Gel Texture (creamy, full-bodied feeling of drinks)
Additionally, soy is a relatively inexpensive crop that can thrive in a multitude of climates consumed by a wide variety of industries (2)
Different Types of Soy: Organic vs GMO Soy
The NON-GMO Project defines genetically modified organisms (GMOs) as living organisms whose genetic material has been artificially manipulated in a laboratory through genetic testing.2 As we learned in the historical timeline of Soy, scientists have been modifying soybeans for materialistic goods since the early 1990s. This doesn't mean that all soy is GMO and doesn’t mean that there isn’t organic soy available for purchase and consumption in the human diet.
Soybean farmers in the United States have the choice, based on production methods or access to direct end-user markets, to plant biotech, organic, or conventional soybean seeds on their farms. A farmer that produces soybeans for fuel and plastic-like goods isn’t the same farmer that produces soybeans for human consumption and visa versa. That being said, of the 76 million acres planted in 2013, 94 percent (more than 70 million acres) of the seeds were for biotech use.
Organic soybeans were planted on nearly 132,411 acres, comprising of 0.17 percent of the total soybean acres planted in 2011.3 The majority use for GMO soybeans are not used for human consumption, but rather produced and exported to China (the world’s largest importer of soybeans) for the production of materialistic goods (think tires, plastics, toys, clothing, etc.).4
Why are Soybeans Genetically Modified Organisms (GMOs)?
The simple answer: soybeans aren’t just used for human food or feed use and consumption and the majority that aren’t intended for human consumption have been heavily modified. Soybeans have been scientifically discovered to be able to be transformed and used in many non-food (industrial) products. Soybeans have been genetically modified in the industrial use area to yield stronger bonds and resemble plastic made from oil without the actual use of oil.
Soybeans can also be genetically modified to be more resilient against infection, disease, and pests. In a positive light, there are organic farmers within the United States that provide soybeans without any type of genetic modification or pesticide use. When looking for a soy product to consume in your nutritional lifestyle, we recommend making an organic selection.
Soy is very similar to all other foods in that, while it is and will continue to be researched, expert scientists still don’t know everything there is to know about soy. While there have been some research studies done in recent years that elude to soy being negative for human consumption, the food has been consumed for thousands of years and soy actually does have a good amount of beneficial properties to it.
The controversy surrounding soy comes down to this: where do you get your information from and is it conclusive? This is why we turn to fact, not fiction or opinion, for our information. Next, we’ll learn more about what is good (and bad) about soy in effort to come to the conclusion if soy is right for you and your dietary needs.
Soy Benefits: In Favor of Soy
Is soy good for you? Nutritionally, yes! Soybeans are a significant source of nutrients and are even found to have anticancer phytochemical molecules. Is soy bad for you? When you overconsume one type of food, or in this case soy, yes, soy can be bad for you!
What’s in soy? Soy-containing foods are high in protein, low in calories, carbs, and fats. Soy foods are a complete source of protein, meaning that they contain all nine of the essential amino acids. They don’t contain any cholesterol and are easy to digest within the human GI. Soy protein is higher in quality than other legume proteins and soy protein has been clinically shown to lower circulating LDL-cholesterol levels while modestly lowering blood pressure.6
The main phytochemical compounds found in soy are the polyphenols called isoflavones, which can help prevent illness and promote good health. Isoflavones are technically a plant hormone (phytoestrogen) that resembles human estrogen in chemical structure.
Soy & Cancer: The Answer Might Not What You’ve Heard
While many people create controversy over the structure of isoflavones found in soy, the striking resemblance between the two can actually provide anticancer benefits and anticancer properties because of it’s ability to block the activity of enzymes involved in the uncontrolled growth of tumor cells.
Hormone-dependent cancers, such as breast cancer and prostate cancer, rely on high levels of hormones within the blood to create uncontrolled growth and cancer within the body. Dietary elements, like regularly consuming soy products can help control sex hormones, like estrogen, to help prevent cancer or slow/halt the growth of cancerous tumors.
As compared to Asian populations (high soy consumption), Western diets consume higher amounts of animal fats and less of soy products, which intrigued scientists to embark on a 10-year long study of 21,852 Japanese women that consumed miso soup and an isoflavone intake of 25mg daily. They measured the women’s risk of breast cancer and found that consuming high amounts of isoflavones regulated hormone levels therefor starkly decreasing their risk of developing breast cancer.5
Soy and Fertility
Soy may actually be beneficial to those looking to increase their fertility as long as soy is consumed in moderation and not excessively (such is the rule of thumb with any food!). Soy foods in a study published in March 2016 were used to evaluate whether soy consumption modifies the relation between urinary BPA levels and infertility treatment outcomes among women undergoing assisted reproduction. Scientists discovered that regularly consuming soy foods may actually protect against the adverse reproductive effects of BPA by regulating hormone levels within the blood.6
In Opposition of Soy: Inconclusive Scientific Evidence
Just like any other food out there, research about the pros and cons of soy haven’t been solidly established and there’s a lot of conflicting information out there, especially on the internet. According to Harvard Medical School, soy foods can help you build a healthy diet, but be mindful about what you’re pushing off the plate if you’re adding or subtracting soy from your nutritional lifestyle. Dr. Meir Stampfer, professor of nutrition and epidemiology at the Harvard T.H. Chan School of Public Health says “I would not necessarily recommend eating more soy if your baseline diet is already healthy.”.
Additionally, the link between soy and menopause the controversy is a bit absurd – soy hasn’t been conclusively found to be harmful to women’s health, whether pre- or postmenopausal. The harmful effects in question with the proposed link between menopause and soy has to do with the formulations enriched with isoflavones used to treat side affects of menopause, which have very little to do with soy foods. You can read more about how isoflavones and soy are manipulated and used for pre- and postmenopausal pharmaceutical patented drugs by clicking HERE.
Another controversy surrounding soy is the topic of moobs, or man boobs. So should you avoid soy as a man? Is soy bad for men? No, it’s not. Should men avoid soy products? No, they shouldn’t. Studies are skewed and flawed because many lack control groups, have small numbers of test subjects, and neglect crucial date leading to inconclusive assumptions and predictions. In a 2010 meta-analysis published in Fertility and Sterility, studies show no effects of soy protein or isoflavones on reproductive hormones or testosterone production in men.7
How Much Soy Is Too Much
You may be finding yourself saying, “well, if soy isn’t bad, how much soy can you eat?” and the answer is this – the general recommendation for a varied diet (including a balanced range of nutrients) is about 15-25 grams of soy foods per day according to Toby Smithson on behalf of Academy of Nutrition and Dietetics8.
That doesn’t mean you should get all of your protein needs from soy (we don’t recommend this at all) but instead, the amount should be used as a guideline to a soy upper limit. Too much of anything is bad, including soy.