Soy foods enjoyed heightened popularity during the early 2000’s, due to a rise in awareness of lactose intolerance, allergies, and chronic disease prevention. Big health claims were made, and by 2006, the United Soybean Board announced that 82% of Americans viewed soy foods as healthy. But the hype caused critics to pop up and publish entire “anti-soy” books. Eventually, some of the soy health claims were retracted, and consumers were left with a bad taste in their mouth. The tables had turned and soy sales were on the decline. Today, Americans are divided on the topic, with 50% buying soy each month. So what is the truth? Is soy healthy? In this post, we’ll cover the facts and share insights on this controversial dairy-free topic.
This post is for informational purposes only and is not intended to diagnose, treat, or make any medical or dietary recommendations. Always consult your physician if dealing with acne or any other skin condition, and before any change in diet.
Is Soy Healthy? What Everyone Agrees On
There are a few soy facts that receive little argument from either side of the debate:
- Soy provides a complete source of dietary protein. Unlike most plant proteins, soy contains all of the essential amino acids in one neat little package. It’s typically touted as a high-quality protein.
- Soymilk rivalsdairy milk in natural protein. It’s the only pure milk alternative on the market (just water and soybeans needed) that contains 8 grams of protein, just like dairy milk. Other types of milk alternatives have to be supplemented to achieve those nutrition levels. This is one of the main reasons that soymilk is the only dairy-free milk approved by the National School Lunch Program in the U.S.
- Soy is a nutrient dense food. Beyond protein, soy beans are also a good natural source of antioxidants, iron, fiber, omega-3 fats, dairy-free calcium (especially certain forms), magnesium, manganese, vitamin K, folate, riboflavin, potassium, and other key micronutrients. This is a great list of nutrients for people on a dairy-free diet.
- Soy is a top allergen. Like dairy, and any other food, it is possible to be allergic to soy. Soy is a legume, and it’s one of the top nine allergens in the U.S. Only about .4% of children have a soy allergy, but the likelihood increases in kids that have other food allergies. One small study found that 14% of children with a milk allergy also had a soy allergy. Your physician might recommend complete avoidance of soy if a soy allergy is suspected.
The Whole Soy Story
Once you get past the facts above, the pro-soy and anti-soy camps diverge. For every study that touts soy in the prevention of heart disease, cancer, osteoporosis, menopausal symptoms, etc., there seems to be an opposing one that pops up. But here are some important things to understand about challenges with soy studies.
Most experimental food studies use concentrates or isolates
Observational research typically includes concentrated and whole foods. But the vast majority of soy intervention studies use soy protein concentrate or soy protein isolate in high quantities. Whether the results are positive or negative, this poses two real world problems. First, by using concentrates, the study participants (often rats) are typically ingesting proportionately higher amounts of soy protein than is realistic for your average person. Second, consumption of extracted components like isolates could produce different effects in the body than the food as a whole. Isolates have an array of naturally-occurring chemical compounds stripped away that may work in unison.
Though there are many studies that support soy as healthful, the majority of the negative soy studies used high levels of soy protein isolates for their research. By using concentrates or isolates, the soy studies are merely finding potential benefit or detriment for certain populations in high level supplementation. They are rarely looking at regular dietary consumption of whole soy foods by your average consumer.
Observational studies have limited scope and excessive variables
Specific food observational studies are difficult, since you must factor out lifestyle differences, regional differences, possible genetic differences, and a whole array of dietary and food differences. In many cases it also involves participant memory recall and truthful compliance. This is why you might see completely opposite results on the same topic from different observational studies. It’s all about the group selected, what’s reported, variables considered, and how the researchers gather and interpret the data.
As an example, many soy observational studies have been done with Asian populations, since soy is a bigger part of Asian diets than Western diets. But Asians typically have lower, sometimes much lower, rates of many of the health issues focused on in these studies than people in Western countries. The fact that Asians consume much more soy on average than a group that has a higher incidence of the condition almost nullifies any anti-soy results. It suggests the scope of the study is too limited, and implies other factors might have a bigger role than soy consumption.
So is Soy Healthy for a Dairy-Free Diet?
It’s well documented that Asian cultures have healthfully consumed soy foods for centuries. Although reports differ as to the actual amounts, most agree that Asians do consume far more dietary soy than Americans. A 2003 report from the UN Food and Agriculture Organization, estimated that on average, the Japanese eat nine times more soy protein than Europeans and North Americans.
In Asia, fermented soy foods were the traditional modes of soy consumption. And to this day, they are considered to be quite healthy in most circles. Popular fermented soy foods are tempeh, natto, and miso. Non-fermented soy foods, like tofu and soymilk, were introduced later, but are now the predominant types of soy consumed in Asian countries. Both types have been linked to positive health benefits in many studies.
Some of the key concerns raised about soy products are related to the weak estrogen-like activity of soy isoflavones. Consequently, hormone-related conditions like thyroid disease and breast cancer have been at the forefront of these conversations. Yet, a 2022 review looked at 417 studies and determined that soy consumption did not have a negative effect on thyroid function or thyroid hormone levels.And breast cancer incidence is much lower in Asia. In fact, one study showed that Asian Americans, who tended to eat less soy, had a higher risk of breast cancer than their Asian counterparts. And those Asian Americans saw a decrease in breast cancer incidence when they increased their soy consumption.
This isn’t to say soy is the magic ingredient for good health and that it’s the perfect food for everyone. I don’t believe any single food is. The fact is, only you and your doctor can decide if a food is right for your specific dietary needs and health concerns.
The Soy “Rules” that I Follow
For my personal dairy-free needs, my doctor and I have found that whole soy is a healthy option. These are the personal choice “rules” that I generally follow in regards to soy intake. They are based on my own research and body. It is up to each individual and their physician to decide what diet is best for them.
- Limit soy protein isolates (sometimes labeled as just “soy protein”), soy protein concentrates, and soy isoflavones as much as possible. They are used in protein bars and other processed foods. I don’t strictly avoid them, but opt for whole foods over isolates when possible.
- Avoid GMO soy when possible. We really don’t know much about the long term effects of GMOs on us or the environment, so I prefer to steer clear at home. Brands like Silk and Edensoy are non-GMO and even have organic options available. Under current government guidelines, certified organic foods must be non-GMO.
- Enjoy whole soy foods in moderation, as I would any other single food. This includes consuming conveniences like soy milk, soy yogurt, edamame, and tofu that are made with whole soy.
- Incorporate fermented whole soy foods whenever the opportunity arises. Miso adds a wonderful “cheesy” element to sauces. Tempeh has a stronger flavor and denser texture than tofu, so it can be more pleasing chopped up in sauces. Natto is definitely an acquired taste.
