Don’t Give in to Tofu Tomfoolery — Soy’s Negative Rep is Overblown

<p>What seems like such a simple food in the grocery store has been caught up in debate over whether it is truly healthy. Tofu is found in a million recipes and is a staple of Asian and vegan diets, and it generally has a rep for being a healthy food, but that’s not the case in every quarter: there are concerns out there regarding its effect on heart health, breast cancer, and that it even “feminizes” men (more on that later).</p> <p>This might sound like news to you, but the tofu-averse are understandable given that the word from experts has fluctuated over the years. There has been mixed messaging over whether it really is beneficial for your heart, for example.</p> <p>The bottom line is that tofu is a fantastic addition to a healthy diet for most people. Although studies seem to hold conflicting findings on soy products, experts say this is down to the huge variation in how it is studied. More recent population studies have concluded that it has either a neutral or even positive effect on numerous health issues.</p> <figure><img alt="Tofu and broccoli | Source: vedanti/Pixabay" src="https://cdn.storymd.com/optimized/1dmjDXuLqp/thumbnail.jpg" /> <figcaption>Tofu and broccoli. <em>Source: vedanti/Pixabay</em></figcaption> </figure> <h2>What’s in that gooey block of tofu?</h2> <p>Tofu (also known as bean curd) is made of soybeans, water, and a coagulant (such as calcium sulfate) that are pressed into a block. At the supermarket you’ll find variations according to firmness, reflecting the water content. </p> <p>It’s high in protein and has all the essential amino acids your body needs, making it an excellent alternative to meat. It’s also a good supply of fats, carbs, and an array of vitamins and minerals. A 3.5oz (100g) serving of firm, calcium-set tofu offers:</p> <ul> <li>Calories: 144</li> <li>Protein: 17 g</li> <li>Fiber: 2 g</li> <li>Fat: 9 g</li> <li>Carbs: 3 g</li> <li>Calcium: 53% DV (daily value)</li> <li>Manganese: 51% DV</li> <li>Copper: 42% DV</li> <li>Selenium: 32% DV</li> <li>Vitamin A: 18% DV</li> <li>Phosphorus: 15% DV</li> <li>Iron: 15% DV</li> <li>Magnesium: 14% DV</li> <li>Zinc: 14% DV</li> </ul> <p>With such a diversity of nutrients and relatively few calories, tofu is considered a highly nutrient-dense food.</p> <h2>Tofu’s wonky history in heart health</h2> <p>Tofu, soy products, and isoflavones (natural plant compounds that act as phytoestrogens) have an inconsistent image in the United States. Back in the ‘90s, the FDA gave the green light for manufacturers of soy products to say they protected against coronary heart disease. Flash forward to 2006 and the American Heart Association issued an advisory saying that heart health benefits from soy isoflavones were “minimal at best”.</p> <p>The FDA subsequently worked at reevaluating the status of the claim, and there was a proposal to revoke it in 2017. This was because several studies presented findings that were inconsistent regarding the relationship between soy protein and heart disease. Some of these inconsistencies may have happened because soy was compared with such a large variety of alternative foods.</p> <p>More recent research has flown against the idea: a 2020 study examining data from over 210,000 healthcare professionals found that eating one serving of tofu a week lowered the risk of heart disease by 18% compared to those who rarely consumed it.</p> <p>A separate study in the BMJ reported that replacing red meat with plant proteins including soy foods, beans, and nuts was connected to a 14% lower risk of heart disease. Soy foods are thought to be generally beneficial for the heart and blood vessels because of their polyunsaturated fat, fiber, vitamins, and minerals. </p> <figure><img alt="Fatty Diet and Heart Disease | Source: TheVisualMD" src="https://cdn.storymd.com/optimized/j8dnX2cvAn/thumbnail.jpg" /> <figcaption>Replacing red meat with plant proteins, including soy foods, can lower risk of heart disease. <em>Source: TheVisualMD</em></figcaption> </figure> <p>Research published in a European journal involving roughly half a million people in China found that participants without a history of cardiovascular disease who ate soy four or more times a week had a lower risk of dying from a heart attack. </p> <h2>The whole “soy boy” thing</h2> <p>One of the more bizarre aspects of the gym bro side of the internet is people harping on about how soy products (including tofu) are bad for men because they stimulate the growth of breasts (gynecomastia). Others just say it makes you more feminine in some vague, generalized way.</p> <p>Given that large swathes of the world consume tofu and soy products regularly and have done so for millennia, this isn’t very credible. Nonetheless, you’ll find plenty of articles talking up soy’s “negative effects”, with the reasoning being that soy has lots of isoflavones, which have a chemical structure similar to estrogen. Soy therefore acts as estrogen in the body, they say, triggering feminizing effects.</p> <p>Nope.</p> <p>Multiple meta-analyses on the topic have failed to back up the assertions from this crowd. A 2021 review covering 41 studies and 1,753 men echoed the findings of a 2010 meta-analysis, reporting that “…neither soy nor isoflavone intake affects total or bioavailable circulating testosterone concentrations in men.”</p> <p>Isoflavones were shown to not significantly alter estrogen levels in men across nine studies, according to another review, even when consumed at levels found in a typical Japanese diet. These compounds may be similar to human estrogen, but they are much weaker, and they’re also markedly different from synthetic estrogen, which may contribute to certain health issues.</p> <h2>Breast cancer</h2> <p>One longstanding claim against soy is that its estrogen-like isoflavones could promote breast cancer, but many studies have shown the opposite. Women who consume soy products have been found to have no greater risk or even a lower risk of developing breast cancer than those who eat little or none. However, the available evidence is too limited to draw firm conclusions.</p> <p>It’s true that estrogen can fuel certain cancers and isoflavones bind to estrogen receptors in the body, but they only cause weak estrogenic activity. Isoflavones are structurally different from bodily estrogen, and the plant-based type doesn’t convert into regular estrogen when we consume it. That means it doesn’t drive cancer growth the same way bodily estrogen does. </p> <p>One of the sources of concern is evidence showing that soy can stimulate breast cancer in rodents. However, soy metabolizes differently in animals, and the outcomes in these studies have failed to be replicated in human studies.</p> <p>Human studies have shown that soy seems to have either no effect or reduces breast cancer risk (particularly in Asian countries where intake is higher). This could be because isoflavones block the more powerful natural estrogens in the blood. The effects of soy may vary according to menopausal status, the age of the consumer, and the type of breast cancer.</p> <p>Both pre- and postmenopausal women have been found to experience benefits in preventing breast cancer. Postmenopausal women on a soy-rich diet before and after a diagnosis could be 28% less likely to experience a recurrence once their cancer is in remission, according to a 2018 review. Similarly, an epidemiological study of 300,000 Chinese women found that both pre- and postmenopausal women may have up to a 27% lower risk of cancer.</p> <p>“Soy is actually helpful for both preventing cancer and reducing its recurrence,” said Julia Brockway-Marchello, a Memorial Sloan Kettering Cancer Center breast medical oncologist. “When we look at populations of people who have soy-based diets, we’ve seen lower rates of cancer, especially in breast cancer.”</p> <p>There appears to be some benefit for at least certain groups of people from regularly eating soy-rich foods like tofu, but more research is needed to figure out which populations would benefit most.</p> <h2>Final word on tofu</h2> <p>Soy products like tofu are nutrient-dense and can be safely consumed, barring those with an allergy. It is also likely to offer health benefits, especially when used as an alternative to red and processed meat. Soy has been associated with lowered cholesterol and may even help stroke patients to recover.</p> <p>“Soy is a great alternative to animal protein to include in your daily diet,” commented Christie Siebel, a senior clinical dietitian at MD Anderson Cancer Center. “There’s no reason to avoid eating soy.”</p> <p>With that in mind, there are some things to keep in mind when cooking tofu. A lot of people aren’t keen on the bland taste, but there are lots of ways you can spice it up. Remember, however, that not all these ways are good for you as preparations with excess sugar or salt can do damage. </p> <p>Tofu and tempeh (made from fermented soybeans) absorb the flavor of whatever you cook them with, making them akin to a blank canvas for taste. They can be sautéed, baked, crisped in an air fryer, or simmered in a sauce. Other ways to incorporate soy protein include snacking on soy nuts, steamed edamame, or using soy milk (unsweetened) as part of your smoothies.</p> <h2>More on Soy</h2><ul><li><a href="https://soulivity.storymd.com/journal/jb8ap2l02j-tofu" target="_blank">Tofu (Bean Curd)</a></li><li><a href="https://soulivity.storymd.com/journal/mrpxqavizj-soy-allergy" target="_blank">Soy Food Allergy</a></li><li><a href="https://soulivity.storymd.com/journal/wdl2akou4j-wellness-and-nutrition-protein" target="_blank">Wellness and Nutrition: Protein</a></li></ul>