Soy - Good or Bad?
Updated: Nov 11, 2020
I just read a recent article about a study which tracked more than 52,000 North American women over an 8 year period. The study concluded that 1/4-1/3 cup of dairy milk daily was associated with a 30% increased risk of breast cancer. This may come as a surprise to many but it didn't shock me especially after reading The China Study. Dr. Colin T. Campbell is famed for his groundbreaking work in one of the most comprehensive 20-year nutrition studies ever done. Growing up on a dairy farm himself, Dr. Campbell didn't set out to prove that milk was bad. He set out to show the importance of protein. What he discovered would forever change the way he looked at nutrition. He started testing casein, a dairy milk protein, on lab mice and discovered that increasing casein in mice led to increased tumor size while decreasing casein caused the tumors to shrink. He was literally turning cancer on and off! This blew my mind! In my post on calcium, I talk about IGF-1, the growth hormone found in cow's milk. This is the hormone that helps grow a calf into a fully grown cow in 6 months. Scientists are linking this growth hormone to cancer. So no, I wasn't surprised by the study given what we know about casein and IGF-1.
The study didn't surprise me but what did shock me last year was a representative attending my daughter's school to extoll the benefits of milk. She was essentially marketing milk to classes. I happened to be in the school parking lot when she arrived with inflatable cow in hand. This was timely, right after Canada's Food Guide all but removed dairy from the guide. I mean, when was the last time something like that happened at the schools? The 1950s?! With all of the alternative milks out there not-to-mention allergies and lactose intolerance, why would anyone think this was a good idea? Someone at the school board clearly wasn't thinking straight. If you're going to extoll the benefits of cows milk, why not soy milk or oat milk? Why not broccoli? I'd love to see a rep come in and talk about any fruit or vegetable but there's no such thing as a broccoli board and there's no marketing budget behind asparagus. This was all very confusing to me because this was the same school that showed Cowspiracy to its students and lobbied for meatless Monday. Anyways, despite what you might think, I'm actually not that parent who usually phones the school with complaints however this was one situation where I felt a phone call was warranted.
But what about soy? The ever-controversial soy. Doesn't it increase estrogen and isn't estrogen linked to cancer? Interestingly, soy milk in this study didn't show any ill effects on the group of women. Whenever I'm not sure about something in the nutrition world, I refer to Dr. Michael Greger at nutrition facts. He has many videos on the soy topic. Check out this to get you started. Soy contains phytoestrogens which in studies have been shown to actually suppress estrogen. Dr. Greger talks about this and how people hear "estrogen" in the word "phytoestrogen" and assume it's bad when in fact, studies on soy have shown that its phytoestrogenic effects decrease chances of breast cancer as well as breast cancer recurrence. In 2012, a large study was conducted on almost 10,000 U.S. and Chinese breast cancer survivors. The study found that those who consumed soy had a "statistically significant reduced risk of recurrence". In fact, a 25% reduction.
Let's be clear though - when we talk about soy we're not talking about isolated soy protein which is found in many processed foods. No one should ever claim that "fake" deli meat or some of the new acclaimed fake burgers are health foods. The less processed the soy the better. Traditional Japanese diets have incorporated healthy sources of soy for decades in the form of miso, edamame, tofu and tempeh. Interestingly, they are a population that has some of the lowest incidents of breast cancer.
I shared the 52,000 woman study on my social media which was then shared by a couple of friends and received some interesting comments one of which was that the study is inconclusive and confusing and we should continue drinking milk as a healthy source of calcium for our bones. I don't normally engage in the chitter chatter on social media and I certainly don't pretend to tell people what to eat and not to eat. I just like to share information as I see it. However, I couldn't keep quiet on this one. I know there's conflicting information out there which is meant to confuse. Confusion quells change and causes people to just keep doing what they're doing even if it's not working for them. Now this was an observational study which can have some confounding factors. I agree that further study needs to be done on this subject however, even if there's a question in your mind that the information might be true, shouldn't we look at it? If not for ourselves but for our daughters, sisters, aunts, mothers? Might there be a reason that dairy was essentially dropped from Canada's Food Guide? The fact of the matter is we don't need dairy to thrive. We can do what the cows do and get calcium from other sources. In my blog, I mention some of those sources. Of course, everyone should conduct their own research and talk to their own health professional (I tend to exercise caution in the latter though as many doctors get the equivalent of only a few hours of nutrition information in medical school).
Here's the skinny on soy as I see it. I personally consume soy (the organic, non GMO variety). I like unsweetened soy milk (and a variety of other plant milks) as an alternative to cow's milk. I love making a delicious bowl of general tso's tofu and my kids love snacking on edamame. I consider these to be healthy foods. I don't overdo it as I wouldn't overdo it on any one form of food. However, I do think labelling soy as universally "bad" is doing a great disservice to people.