DISCLAIMER: This blogpost is not meant to replace any kind of professional health or medical advice. This is just to share my own exploration, experience and personal deductions on the evidence that has been put out there about soy. The dairy and soy industries are both very powerful and can easily influence what is being published out there. I recommend that you keep an open mind and stay varied with the information you seek and receive on the topic, for you to be able to draw your own conclusions.
“Adoi, I cannot take soy!” I have been told by a few customers when I serve food from my food booth containing tofu. The bad reputation swirling around soy intake has been prevalent amongst the Malaysian community since I can remember… Although up to now, it has only been conveyed to me as hearsay. What I’ve heard is that it can cause breast cancer, gout and man boobs. When I first came out as a vegan, soy was one of the most arresting apprehensions that people addressed to me, and its prominence as a dietary concern remains. The controversy has heated up once again with IKEA’s move to completely switch their soft serve dairy ice cream to soy-based ice cream (which I’ve tried and hits the spot in terms of taste and budget, to say the very least).
So I decided to bring up the findings I’ve recently had from long hours of digging around the internet to see what can be really said through studies on this protein-packed yet notorious little bean.
Soy contains a substance called isoflavones, with a chemical structure similar to the female sex hormone, estrogen. This is one of the things that people freak out about: that taking in extra hormones through our food will upset our natural hormonal balance.
That, is true. But there are fine details that the general public has seemed to miss.
I have read that isoflavones does seem to mimic the effects of estrogen whilst at the same time blocking other effects. This, however, appears to have beneficial outcomes, which I will get to later.
What helps to put things into perspective is that isoflavones are 100 to 1000 times weaker than human estrogen.
A more worrisome matter than soy is that most dietary estrogen, which happens to be identical to actual human estrogen, comes instead from dairy, meat and egg products.
Studies show that Genetically Modified Organisms (GMO foods) show no adverse effects on humans, but I’ve also been exposed to trustworthy sources that throw doubt on this revelation. Taking into account the environmental and human rights issues surrounding GMO crops, those alone are decent enough reasons for me to gravitate towards labels that say ‘GMO-free… not just on soy products, but any other packaged foods I buy.
The link between soy and gout is an unsound belief that almost half of Asian healthcare professionals stand by, as clinical studies have shown that the rise in uric acid levels from soy intake is insubstantial enough to cause alarm.
Soy is known to be a goitrogen, which adversely affects thyroid hormone production by interfering with the uptake of iodine. Various medical-based sources have explained that as long as you have a healthy thyroid gland and maintain a balanced diet that includes iodine (through food e.g. seaweed or supplementation), soy is safe to consume.
That being said, there is also another issue of supplementing oneself with too much Iodine which may lead to thyroid dysfunction too. Apparently there’s a very delicate balance to it! So to play safe, I personally take my Kelp supplement only once in a while.
Before doing my own thorough research, my general impression based on what I had heard was that soy helps to manage cholesterol. My overall research on soy took place last year, during which I came across a study published by the American Heart Association (AHA) that deduced that soy helps to reduce LDL (bad) cholesterol. It has now become a dead link, and I can’t help but have strong suspicions as to why. (If you have watched the documentary What The Health, that flings a spotlight on dangerously hypocritical actions exercised by the AHA, you may understand why.) Trying again now, I have found the findings of a 2006 study, linked to AHA (which may or may not be related to the study in the dead link) that shows that soy does help to reduce bad cholesterol, but the reduction percentage wasn’t worth boasting about. Given the strange circumstances of researching this part of the soy story, I’m not too sure what to make of it. I haven’t taken a cholesterol test lately to see what my levels are like now, but I’m a plant-based eater and currently doing the most cardio exercise I’ve done in my life to support my open water swimming pursuits. For now, I’d continue to consume soy on the basis of other health benefits.
It is interesting to observe the popular notion of soy being an accomplice in causing breast cancer, as majority of the links I’ve come across have disclosed opposite outcomes. One study has shown that consuming one cup of soymilk or half a cup of tofu a day reduced breast cancer risk by 30 percent.
In the comprehensive Shanghai Breast Cancer Survival study in 2008, spanning over 7 years and involving over 5000 female participants, breast cancer survivors who regularly consumed soy reduced cancer re-occurence by 32 percent.
The ongoing Okinawan Centenarian Study, which investigates the lifestyle of over 900 residents in Okinawa aged 100 years and over, shows that female subjects have notably low occurrences of age-related health complications such as hot flashes, hip fractures, or coronary heart disease. This is linked to the high levels of soy they consume. It’s also fascinating to read that Okinawans have 80% less breast cancer and prostate cancer occurrences than dairy-dependent North Americans.
Speaking of prostate…
Cancer prevention is not only detected in women. Study results reveal an association between soy consumption and a 26% decrease in risk of prostate cancer.
In terms of the effect of soy on male fertility, a study has shown that soy does not affect testosterone levels, sperm concentration nor sperm quality.
How about gynecomastia, also known as man boobs, also known as ‘moobs’? Most medical experts have said it’s not an issue worth worrying about. A 2005 study has shown that the raised estrogen levels in soy-eating men are statistically insignificant. There is only ONE case study I found where a 60-year-old man developed soy-induced breasts. It was discovered, however, that the patient was guzzling down 3.4 LITRES of soymilk EVERY DAY. If you know of a guy raiding a Jenny Hong truck on a daily basis to get a similar fix, please fill a brother in.
How about feeding soy to your kids? One study shows that there doesn’t seem to be any negative effects of infants being fed soy-based formula as opposed to a dairy-based one. Another study has revealed that an increased intake of soy at most life stages – even childhood – was associated with reduced breast cancer risk (something a little easier to read here). On the other hand, recent research points to childhood soy intake being linked to disease. Although there doesn’t seem to be enough studies to lead to a golden truth, the review of various studies suggests that soy is safe to include in a child’s diet, on the condition that it is a balanced one.
After all of this research, the one thing I can take away from all this is that soy is beneficial when taken in moderation, but this goes for everything else we eat. Too much of one thing is not good for anyone in the long run, no matter how big a halo hovers over a food type. I eat a fair amount of soy; I’d say that every third to fourth meal I eat has tofu, tempeh or any other soy-based food and, if it is in there, makes up about a fifth of the portion of the meal. So far I haven’t experienced any negative outcomes. But I’m in no place to say that this will be the same for you, as my body is unique to me. My advice to anyone – at any age – still stands at maintaining a balanced, broad-spectrum diet of fresh produce, nuts, pulses, legumes and grains, and to pay constant attention to what your body is telling you. Wishing you all the best in your journey of discovering what helps you and your family thrive!