Understanding How Soy Foods Impact Your Health

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Hi Sweet Friends,

Oh, boy, we’re talking about soy. It’s a hotly debated topic these days, especially in the plant-based community. You’ve probably heard mixed reviews on this elusive bean — some good, some bad and some very ugly. I know it can be frustrating, but don’t throw your tempeh piccata in the trash just yet. With a little extra smarts, you can make an educated decision on how, why and if soy should be part of your diet. I certainly include it in mine, but that doesn’t mean I’ll be signing up for a soy-dog-eating contest anytime soon. As you’ll learn in today’s blog, organic, non-GMO soy foods can provide many benefits when eaten in moderation.

What types of soy foods are best, and how much should you eat?

In my fridge, you’ll find a variety of whole and minimally-processed soy foods, such as edamame, tempeh, miso and tofu. These foods land on my plate 2-3 times per week, although I tend to use tofu the least since it’s one of the more processed choices in my soy repertoire. They’re all rich in nutrients, antioxidants, protein, essential omega-3 fatty acids and phytoestrogens. A word to the wise, almost all soy is genetically modified. That’s why I always buy organic and search for the non-GMO label. It’s best to look for both stamps of approval, since organic does not guarantee 100% GMO-free food.

Eating soy as nature intended (or very close to it) can be beneficial to your well-being in a variety of ways. Soy protein and omega-3s are important for heart health. They also keep your arteries clear and cholesterol levels low. And contrary to some unsubstantiated fear-based claims, phytoestrogens may actually help reduce breast cancer risk among premenopausal women (more on soy and cancer in the following section). In addition, whole soy foods are easier to digest and taste better than their processed cousins. Plus, the microflora in fermented soy products, such as miso and tempeh, are your belly’s BFF.

Again, keep processed soy foods (and processed foods in general) to an absolute minimum. You’ll often find soy protein isolate or concentrate — both at the top of my list to avoid—on their ingredient lists. Faux chicken nuggets, soydogs and other fake meats not only contain processed soy, but a laundry list of food additives and preservatives as well. While these foods aren’t the devil, they certainly aren’t real, and therefore should never be a dietary staple. Think of them as an occasional novelty. The one exception I’ll mention is for those transitioning from a meat-heavy to a plant-happy diet. Eating faux meats and cheeses as a crutch can be helpful, but they definitely shouldn’t hold center stage for long.

We often cling to processed soy foods because of our culture’s protein paranoia. News flash sweet friends — protein doesn’t need to be the main event on your plate at every meal. Now I’m not saying that you don’t need protein, you absolutely do. But if you’re consistently eating a varied, plant-based diet, filled with beans, legumes, nuts, seeds, grains and vegetables, you’re in good shape! And with such an abundance of protein-rich choices in the plant family, are you starting to understand why soy is optional?

If you’re still concerned about protein, simply calculate your daily requirement using the following formula: Your body weight (pounds) multiplied by .36 equals the amount of protein (grams) needed for a moderately active adult. For example, a 140 pound person needs about 50 grams of protein per day. Here are just a few of the high-protein plant foods out there: one cup of lentils contains 18 grams of protein, one cup of quinoa contains 8 grams of protein and two tablespoons of almond butter contain 7 grams of protein. See how easy it can be to meet your protein needs?

Soy seems pretty straightforward when you’re talking about quality and quantity, but the conversation gets trickier when you begin to explore the claims flying around about soy and certain health issues. Next up, soy dangers demystified!

Is there really a link between soy and cancer?

You may have heard that eating soy increases your risk of cancers such as prostate and breast cancer, but the opposite may be more likely. Recent research has shown that lung cancer patients with a history of eating soy have a better survival rate than those who have eaten less or no soy in the past. Men who consume soy have actually been found to have a reduced risk of prostate cancer. And then there’s the most frequently misunderstood relationship — soy and boobs.

When a woman regularly eats protein-rich and phytoestrogen-rich soy foods, studies show that her breast cancer risk drops. Soy’s potentially protective role may be due to its isoflavones which are phytoestrogens (literally meaning “plant estrogens”) and may block some of estrogen’s activity. It could also be the result of various anti-cancer phytochemicals in soybeans. To get the maximum benefit of soy’s protection, some studies show that healthy soy foods should be part of the diet during puberty and adolescence when breast tissue is forming. But that doesn’t mean that you should go soy-crazy. As we’ve discussed, quality and quantity matter. For example, the ladies who participated in the original studies connecting Asian women’s lower breast cancer risk to their regular soy consumption were eating small, moderate amounts of whole or minimally processed soy foods (not buckets of soy jerky!).

So why are people still concerned about soy when it comes to estrogen-sensitive diseases like breast cancer? We’re still not sure how much soy is safe for individuals such as breast cancer patients and survivors, so doctors often recommend that their patients play it safe by avoiding soy completely. This is a very common approach because hormone-sensitive cancer receptors are stimulated by human estrogen and the structure of soy is similar to human estrogen. At the same time, eating soy foods can actually be beneficial to these types of patients and often recommended to patients in moderation during hormone blocking treatment. And it’s also important to mention that soy supplements (not soy foods) are frequently used in the animal studies that point an accusatory finger at soy and cause alarm.

In Life Over Cancer, Keith Block, Oncologist MD, states that based on his review of the current research, “both premenopausal and postmenopausal women with ER+ tumors can safely eat soy foods such as tempeh and tofu about two or three times per week.” Interestingly enough, many of the same doctors who tell patients to avoid soy altogether never mention the abundant amounts of estrogen and other growth hormones found in meat and dairy products! So if you’re avoiding soy as a result of a cancer diagnosis, think twice about animal products as well.

What about soy-loving fellas?

Good news for boys and men! Despite the buzz that “girlie” phytoestrogens may have a negative effect on hormones and fertility for males, there isn’t a single study showing this—nothing linking these issues to soy formula for baby boys or tofu burgers for boy scouts—nada. In fact, a huge study published in 2009 showed that soy food consumption actually reduced prostate cancer risk by 26 percent among soy-strong men. If you’re pregnant and concerned about soy affecting your baby boy, remember that any studies on the subject have involved animals consuming “large” or “high” amounts of soy—not something that fits into our model of eating a moderate amount of unprocessed, whole soy foods.

If you’re concerned about male reproductive issues, it might be time to look more closely at your dairy consumption. A recent study found that consuming high-fat dairy products like cheese and sour cream may lower sperm quality and fertility, perhaps due to the naturally occurring reproductive hormone, pesticides, chlorinated pollutants and/or heavy metals present in dairy foods.

Does soy impact thyroid health?

Another soy misunderstanding: Much like the confusion surrounding cruciferous veggies and thyroid function, soy isoflavones do not cause hypothyroidism or exacerbate hypothyroidism. Research published in the Journal of Clinical Endocrinology and Metabolism studied two groups of women: one group with 2 mg of phytoestrogens (plant estrogens in soy) and one group with 16 mg of phytoestrogens. They found a small percentage of the high-soy intake group had some decrease in thyroid function, but it should also be noted that the high-soy intake group also saw significant health benefits from this increased soy consumption, such as decreased insulin resistance, decreased inflammation markers and lower blood pressure.

You should be aware that soy isoflavones may absorb some of the iodine needed to make thyroid hormones, which could increase the body’s need for iodine. But, as long as iodine intake is sufficient, soy shouldn’t be a problem for the thyroid. Iodine is especially high in sea veggies, which means that miso soup with tofu cubes and wakame seaweed is not only a soothing combo, but also a match made in thyroid health heaven.

Please note that soy foods may affect the absorption of meds used to treat hypothyroidism. If you take medicine to treat hypothyroidism and love soy, check with your doctor so that your dosages can be adjusted accordingly. And still eat seaweed — it’s good for you!

If soy isn’t a great fit for me, what are the best alternatives?

While soy can be a convenient and healthy part of your diet, know that if you’re allergic (soy allergies are quite common), feel congested after eating it or need to avoid soy for other reasons, it’s not an essential part of a plant-based diet and can be eliminated without compromising your health. As I mentioned earlier, plant protein and essential fatty acids are found in a variety of beans, lentils, nuts, seeds, quinoa and whole grains. And soy-free milk, cheese and meat alternatives are widely available today. Be a label detective and choose products with a short list of ingredients you can pronounce. I opt for a variety of nut, seed and grain-based alternatives, such as almond milk, hemp milk, flax milk, nut cheese and grain meat.

For more soy schooling, check out these highly researched and credible resources:

Whether or not you decide to include soy in your diet is very personal decision that only you can make, but hopefully you feel much more prepared to make that choice with this knowledge under your belt.

Peace & edamame,

Kris Carr