What You Need to Know About Soy

Welcome to the Soy World Order

In the last 20 years, the usage of soy products for everything from cereals to protein powders to milk substitutes has skyrocketed. The soy market is roughly $5 billion strong and has been growing steadily since the early 1990’s. With the demand for soy products going up, and the producers looking to capitalize on the public conception of soy products as being universally healthy, today we want to take a look at the history, benefits and drawbacks of a soy-heavy diet.

A Bit of History

Soy Bean History

One of the main arguments for any case is History: if it’s been working so far, it can’t be that bad, right? Many articles about the pro’s and con’s of soy use the supposed consumption of soy over the millennia in Asia as a main counterpoint to any claims that a soy-heavy diet has drawbacks. But are they barking up the wrong soybean?

Unfortunately, the claim that soy’s benefits have been proven over thousands of years is only half true. Soy has been grown in Asia for millennia, but it was originally used in crop rotation to fix the nitrogen content of the soil, which prepares the land for other crops. For most of it’s history as a crop, people weren’t eating it. It was a tool, rather than a food. There’s some debate on when, exactly, soybeans started to be raised as crops, but evidence shows the year to be somewhere between 5000 and 4000 BCE in China. At the least, records from 3500 BCE show that soybeans were being raised there, so at the least humans have been cultivating the plant for about 5,500 years.

It wasn’t until the people growing the plant thought to ferment it that consumption of soy products became common. Something similar to “soy milk” was recorded as being available as early as 82 CE and tofu use was indicated as early as 220 CE. The common condiment Soy Sauce was invented somewhere between the 3rd and 5th centuries CE.

Soy was introduced to North America in 1765 and used for a forage crop, a source of oil, meal (for animal feed) and industrial products, with very little used as food. In the 1920’s, with the Great Depression and starvation sweeping the nation, Henry Ford (yes, that Ford) invested heavily in soybean research for usage in cars and other manufactured products, but the time and money spent in developing soy products had a large impact on advancing it’s use as food.

Today, the primary use of soy is still as an animal feed, but the last 20 years have seen it increasingly included in human foods like protein supplements/substitutes, milk alternatives, cereal additives, and many other options. Using soy protein isolate as a food additive and the consumption of soy milk are large parts of the U.S. diet.

In Japan, the average consumption of soy runs about 8-9 grams of soy products a day (less than two teaspoons). Most of this consumption is of fermented options like Soy Sauce.

In China and Hong Kong, they’ve adopted a heavy consumption of soy beverages – even more than Europe and the U.S.

Countries with large vegetarian populations, most notably India, are exploring soy as a supplement protein source. It may end up being a good alternative for the large, less economically advantaged populations.

Soy Benefits

One thing to note is that most of the data supporting the benefits of soy foods are from more recent studies, and may of these are being funded by the agricultural industry that is selling the soy to begin with. Every benefit reported should be weighed against the drawbacks also being found, but not necessarily reported on by the proponents of the food. That being said, research has shown that soy does, in fact, have potential health benefits if you eat it. Here are some of the claims that are better supported:

Heart Health – Low daily consumption of soy products has been shown to lower your LDL Cholesterol (the bad one). A review of 30 studies shows benefits at about 25 grams of soy per day.

Breast Cancer Prevention – Recent research shows that women who ate as little as one daily serving of soy-foods in childhood and adolescence had lowered risk of developing breast cancer later in life, with as much as a 50% reduction in such cancers (but see Drawbacks, below).

Improving Menopause – According to a review of 17 studies, consuming the isoflavones in soy helps reduce the frequency and severity of hot flashes in some postmenopausal women by about 50% (but see Drawbacks, below).

Prostate Health – Studies in Asia show that men who consumer about 2 servings of soy per day have a reduced risk of prostate cancer (about 30% less likely) and that it may inhibit the growth of extant cancers (but see Drawbacks, below).

Weight Management – Soy is an excellent source of lean protein, cutting out the saturated fats that you find in most meat sources. This can help with weight management, as you consume fewer calories eating soy than you do eating natural meats (but see Drawbacks, below).

Soy Drawbacks

While the benefits of soy in your diet can be compelling, keep in mind that what may benefit one person won’t benefit you. Below are the most well-supported drawbacks to including soy in your diet. Some of these are in direct comparison to the benefits we talked about previously, so it’s very important to weight both sides of the coin before making a decision.

Breast Cancer Recurrence – While eating low amounts of soy in childhood may help reduce the risk of breast cancer, the same effect has not been seen on women in adulthood. In addition, women who have had breast cancer show an increased risk of cancer recurrence when they have soy in their diet!

Worsening Menopause – While some women see a decrease in hot flash frequency and severity, other women see no benefit or even a worsening of symptoms. Unfortunately the only way to know which category you fall into is to include a small amount of soy in your diet. If your symptoms worsen, STOP eating it! If your symptoms don’t improve after about two weeks, it’s a safe bet soy isn’t going to work for you at all.

Male Health – The isoflavones in soy act as a phytoestrogen (plant compound that acts like estrogen in the body), which means that men who consume a moderate to high daily soy volume may develop symptoms of too much estrogen in their body. Such symptoms can include gynecomastia (development of breasts), softening features, mood changes and erectile dysfunction. What’s worse, in some cases mild consumption over as little as six months had permanent side effects on the subjects.

Weight Mis-Management – Soy does not have all the other nutrients that many meats contain, and so diets heavy in soy have a predisposition to lead to malnutrition and being underweight. If you include soy as a major protein source, you need to be sure to also include sources of amino acids, vitamins, dietary minerals, etc. that you would normally be getting from animal proteins.

Thyroid Issues – The isoflavones in soy can inhibit the body’s natural ability to make thyroid hormone, which play a role in many things including metabolism and body temperature. Some studies suggest that over time, consuming soy can lead to hypothyroidism (a condition characterized by weight gain, fatigue and cold intolerance). The good news is that some other studies show that soy has these negative effects only in people deficient in iodine, which is uncommon in the U.S.

Brain Atrophy -Poor performance on cognitive tests, ventricle enlargement, and low brain weight have been associated with higher tofu consumption in mid-life. In the short term, less than 1 oz of soy milk per day can lead to memory loss.

Goiter – Abnormal enlargement of the butterfly-shaped gland below the Adam’s apple (the thyroid)

Allergens – Soy has been classified as one of the Top 8 allergens in the food supply by the Food & Drug Administration, which means it is one of the most commonly reacted to substances for the most people.

Don’t Feed Soy to Babies, Seriously

There are soy-based foods out there marketed for infants, but we’re going to come out right now and say don’t use them unless your kid is literally going to starve otherwise. The drawbacks for babies being provided a high soy diet are way too scary and pronounced to take the chance.

All the issues we’ve seem with soy products and the increase in phytoestrogens is going to be amplified astronomically in infants and toddlers. Mainly, this is because they have a much lower body weight, and can’t deal with the isoflavones as adequately as adults. Baby foods based on soy have about the same content as soy foods marketed to adults, but because of their smaller body weight their proportionate exposure to isoflavones is 6 to 11 times higher than an adult. The isoflavone concentration of soy-based baby formulas is about 0.04 grams per liter. It may not seem like much until you take into account the fact that human breasts milk has an isoflavone concentration of only 0.00005 grams per liter!

So to break that all down:

  • Isoflavones act as estrogens in the body, and can cause issues in high doses.
  • On average, the isoflavone concentration in soy formula is 800 times higher than in human breast milk.
  • Consuming that level of isoflavones in their diet can lead to blood estradiol levels 13,000 to 22,000 higher than in breast-milk fed babies.

So what does this do? It means that all of the negative effects we’ve talked about in adults will occur in infants and children at a highly accelerated rate. Some examples of effects children will experience include:

Goiters – As adults

Thyroid Problems – As adults

Sexual Anarchy -Infants with testosterone levels like that of adult males, and girls showing signs of puberty as young as age three.

Uterine Fibroids – Uterine fibroids manifests as noncancerous growths of the uterus, resulting in pain (pelvis, abdomen, lower back), irregular/heavy/painful menstruation, and abnormal bleeding/distension/cramping. As reported in Environmental Health Perspectives in March 2010; a 4-year, 50,000 participant study found that women who were fed soy milk in infancy had a 25% higher incidence of uterine fibroids by age 35.


There are very specific cases in which consuming soy may be beneficial to your health and well-being, but no matter the use you need to be consuming it is small, manageable quantities. Some specific cases that may apply:

For girls who have already hit puberty and come from a family predisposed to breast cancer, eating small amounts of soy on a daily basis may help reduce the chance that they develop that cancer later in life.

For women who have reached menopause and have severe hot flash symptoms, consuming a small daily amount of soy may help reduce those symptoms. BUT it may also make them worse. Proceed with caution.

For men predisposed to prostate cancer, small amounts of soy daily may help reduce risk of that cancer. BUT signs of feminization or other hormone disorders should be monitored very closely to prevent irreversible side effects.

For people with high LDL cholesterol where medications or other options to lower it aren’t available, a small daily does of soy may reduce LDL by about 10%.

For people who have trouble managing their weight and are not predisposed to any of the conditions associated with overeating soy, a small amount of soy as a replacement for other protein sources may help manage calorie intake effectively.

As you can see, most beneficial scenarios are very specific subsets of the population, and in every case there is still the chance that the drawbacks associated with soy consumption could outweigh the benefits. In the end, soy may be a tool you can use for specific situational needs, but the reality is that other changes to your diet, daily routine, exercise, and negative health habits (like smoking, etc.) will likely have a bigger benefit with lower risk than consuming soy products.

Generally speaking, consuming whole foods that have not been processed – fruits, vegetables, lean meats, some nuts/seeds, and healthy oils – is going to be the best decision you can make for your diet. Soy is not a natural food stuff for humans, no matter how long it’s been growing in China. In it’s 7,000 year history, we’ve been trying to include it in the human diet as a regular factor for a couple hundred years, and at the time when it is being most consumed, we are seeing the worst side effects. It doesn’t take an FBI code breaker to see the pattern, and our recommendation is eat healthy, don’t eat soy, and…

For the love of Gerber, don’t give soy products to babies. Seriously.

Below is a list of references that inform the facts and opinions provided in this article

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