Bite Back with Abbey Sharp - The SHOCKING Truth About Soy: Hormones, Cancer, Fertility, Menopause & MORE!

Starting point is 00:00:00 Soy has been at the center of nutrition debates for years. So of all the rumors, what is actually true? And what does the science actually tell us about its health benefits like protein in comparison to its counterpart dairy? The anti-soil panic may be one of the most disastrous sets of nutrition myths of our generation. Welcome to another episode of Bite Back with Abby Sharp, where I dismantle diet culture rules, call out the charlatans spinning the pseudoscience and help you achieve food freedom for good. Of all the legumes in the legume family, soy has had a lot of highs and lows in the court of public opinion. Depending on what side of social media you're on, it's either now seen as an alternative to menopause, HRT, or an anachron-disrupting supervillain.

Starting point is 00:00:55 But the research tells us a much more nuanced story. So today, we are going to be separate the soy fear mongering from the facts. And now that I've got my profy, let's talk about why soy and nut chickpeas or lentils or peanuts is constantly stirring the controversy. And to do that, we really need to interrogate the mother of all soy claims that soy equals estrogen. So this is the myth that drives almost every other health-based soy fear, because soy uniquely contains natural compounds called isoflavone phytoestrogens. And this is where a lot of people get confused. The word phytoestrogen literally means plant estrogen. So many people hear that and assume that soy contains the same estrogen that our bodies produce. It does not. Phytoestrogens are plant

Starting point is 00:01:53 compounds that have somewhat similar structures to estrogen, which means that they can interact with some of the same receptors in the body. But they're not the same hormone. They bind much more weakly than human estrogen, and they tend to have more selective effects depending on the person, their hormone levels, and the tissue being studied. So in some situations, they may produce a very mild estrogen-like effect, and in others, they may compete with or dampen the effects of stronger endogenous estrogens. It's confusing. I know. So let's take a look at some of the soy health hysteria and where the research shakes out. Claim number one that soy feminizes men, aka the offensive man-boob hysteria. While the whole soy boy argument has, I guess, a nice ring to it,

Starting point is 00:02:48 it's a far bigger reflection of hypermasculinity panic than an actual public health concern. The theory goes that because soy contains these plant estrogens, it may inverse men's natural balance of higher testosterone and lower estrogen levels, resulting in men suddenly growing breast tissue, aka gynecomastia, and also potentially facing infertility due to damaged sperm. Some concerns about soy stem from isolated case reports, including very rare cases of breast tenderness or gynecomystia, but these reports typically involve extremely high intakes. Like in one well-known case study, for example, the individual was drinking nearly 12 cups of soy milk every day,

Starting point is 00:03:39 far more than what most people consume. Not surprisingly, when we control for confounders in actual peer-reviewed research, we can see that the boys are going to be all right. In one large meta-analysis of 41 human clinical studies, they found that neither soy protein nor isolated soy isoflavones impacted men's testosterone or estrogen hormones. As for sperm and fertility, one study on healthy men found that consuming soy isolates did not adversely affect semen quality, nor was it associated with IVF fertilization, embryo quality, implantation, clinical pregnancy, or live birth rates. Honestly, if drinking soy milk did make breasts grow,

Starting point is 00:04:30 we would expect to see huge population-level hormonal problems in Asian cultures where soy foods have been eaten for generations. And literally every Hollywood plastic surgeon would be put out of business. But as I said, the boys, and also those 9021010 docks, are doing just five. fine. This brings me to the next claim that soy messes with our menstrual cycle. And this one deserves a little bit more nuance. Some small studies have examined soy isoflavone supplements providing 45 to 100 milligrams of isoflavones per day, amounts that are generally higher than what most people consume through soy foods alone. These studies found slight changes in markers such as a longer follicular phase, moderately higher, SHBG, and slightly lower free estradiol. For context, three ounces of

Starting point is 00:05:27 tofu provides around 20 milligrams of isoflavones, while one cup of soy beverage contains around 10. And when we look at studies examining usual soy food intake, ovulation, IVF outcomes, and ovarian reserve markers, we do not see evidence of hormonal shifts. Instead, human studies show either no meaningful effects or in some cases potential benefits for IVF outcomes. In other word, your tofu is not going to wreck your fertility or your cycle. And that leads us to one of the most highly debated and high stakes concerns about soy, and that is that it causes breast cancer cell growth. Some breast cancers are estrogen receptor positive. And when estrogen binds to those receptors, it can stimulate the cancer's growth. So for years, oncologists were telling their

Starting point is 00:06:28 patients to avoid soy products out of fear that the isoflavones might do the same. Except that we now know, it doesn't. Soy isoflavones bind far weaker to estrogen receptors, preferentially binding to the ER beta, not the ER alpha receptors associated with estrogen responsive cancer. And in some cases, it may even compete with stronger estrogens to bind to that receptor. So when we look at cohort studies and also in meta-analyses, we see that soy consumption is consistently associated with lower breast cancer recurrence. Breast cancer-specific mortality also generally trends lower, although that finding is not statistically significant in every analysis.

Starting point is 00:07:19 So it's more important to note here that this does not mean soy treats cancer, nor does it mean that high-dose soy supplements are beneficial. Rather, the current body of evidence suggests that including whole soy foods such as tofu, tempe and amami, miso, and soy beverage appear to be safe and may even offer some potential benefits as part of a healthy dietary pattern. So now that we've dealt with the hormone hysteria, the so-called man boobs, the infertility panic, and the breast cancer fears, we need to talk about a different category of soy misinformation. Much of the remaining debate around soy has shifted away from hormones and towards perceptions of processing. But processing alone doesn't determine whether a food is healthy or harmful.

Starting point is 00:08:14 Soybeans are one of the world's major. agricultural commodities because they are incredibly versatile. They appear often in culturally significant foods like tofu, tempe, miso, natto, soy beverage, and edamame. And they are also used to produce animal feed, soybean oil, biofuels, adhesives, inks, plastics, and other industrial products. Because soy has so many different applications, it's easy to assume that all soy products are the same. But in reality, foods made from soy vary wildly on how they're processed and their nutritional profile. So some people may see that soy could be processed into products that humans would never eat directly and then conclude that all soy foods belong in the same category of

Starting point is 00:09:06 processed or unhealthy foods. The health effects of a food depend on its overall nutritional profile, not simply the fact that it is being processed in some way. So collapsing all soy foods into processed junk or franken food because the crop has industrial or highly processed food applications completely ignores how chemistry works. Like just because soybean oil can become like a biodiesel doesn't mean that an amami is suddenly a biohazard. Nor does the fact that we can process soybeans into a high sodium frozen meatless chicken nugget product mean that tofu or soy beverage are now quote unquote ultra-processed junk.

Starting point is 00:09:48 Processed foods are not created equal. In some cases like tofu, where it's literally just soybeans, water, and a coagulant like calcium or magnesium, it is simply making a whole food more easily accessible and digestible. In other cases, it may actually be making a food safer or more nutritious. Another concern people sometimes raise about soy is, pesticide use. Like many conventionally grown crops, some soybeans are grown using herbicides, such as glyphosite. However, regulatory agencies set very strict limits on pesticide residues in foods, and routine monitoring consistently shows that soy foods sold to consumers fall well within established safety limits. So whether you choose conventional or certified organic soy foods,

Starting point is 00:10:38 the evidence supports them as safe and nutritious options. The final myth I've got to address here is this idea that soy is full of, quote, anti-nutrients that deplete the nutritional value of your meal. Like many plant foods, soy naturally contains compounds such as phytates and trypsin inhibitors, which can bind to certain minerals or interfere with protein digestion. However, here's an important part of the story that often gets overlooked. Cooking, soaking, sprouting, and fermenting soy foods significantly reduces these compounds while also improving digestibility and nutrient absorption.

Starting point is 00:11:18 This is one reason why some forms of processing, such as the methods used to make tofu, can actually improve a food's nutritional value. And ultimately, any small reductions in nutrient absorption are far outweighed by soy's overall nutritional benefits. And now that we've explained why soy isn't the hormone-recking, cancer-causing, testosterone-crushing super villain that the internet sometimes makes it out to be, let's shift the conversation to what soy can offer as part of a balanced diet. The evidence suggests that soy isn't just safe to eat. It can also be a nutritious source of high-quality protein and other important nutrients. So soy for when is a built-in hunger-crushing combo that can help you reach and maintain a

Starting point is 00:12:07 healthy body weight and stabilize your blood sugars because it offers very lean plant-based protein in a low-calorie high-volume package. Most soy-based products offer around one gram of protein per 10 calories, which is a premium ratio when weight loss or blood sugar management is the goal. Soy protein is also a heart-healthy alternative to animal proteins that are high in saturated fat, with one large men analysis of 46 trials showing that consuming 25 grams of soy protein per day for about six weeks, reduced LDL cholesterol by 3 to 4%. The plant protein in soy is also a really great option for supporting bones, especially calcium-set tofu and fortified soy milks, which are often fortified with nutrients like calcium, magnesium, phosphorus, and vitamin D3. Now, obviously, those attributes

Starting point is 00:13:03 benefit everyone, but they become even more critical for us women as we enter midlife and begin the paramenopause pilgrimage. When our natural estrogen levels decline, we tend to see more age-related muscle loss, bone loss, increased risk of heart disease, a propensity to gain more belly fat, and other not-so-sexy middle-age gripes. Thankfully, soy understands the assignment. Early research suggests that the isoflavones in soy may help to modestly reduce common menopause symptoms, including hot flashes, vaginal dryness, and eugenital symptoms. While there's no official recommendations for soy intake during parmenopause or menopause, a lot of the research has used the equivalent of around 40 milligrams of total isoflavones, which translates to around a quarter

Starting point is 00:13:58 cup of whole soybeans, one and a half cups of soy milk, 3.5 ounces of extra firm tofu, or 7 ounces of silken tofu. You know, the funny and unfortunate thing about soy is that we have spent decades now debating whether it's dangerous for us, when if it weren't such an affordable, accessible, and culturally significant staple, the wellness industry would probably have been singing its praises for years. But I guess it's hard to build a billion dollar industry around a humble bean. And on that note, that is all that I have for you all today. Signing off with Science and SaaS, I'm Abby Sharp. Thanks for listening.

Bite Back with Abbey Sharp - The SHOCKING Truth About Soy: Hormones, Cancer, Fertility, Menopause & MORE!

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