Truth about soy — it’s good, to a point |

Truth about soy — it’s good, to a point

Dr. Greg Feinsinger
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Last week’s column was about the health benefits of daily consumption of legumes such as beans, lentils and chickpeas. Soybeans and soy products deserve a separate column because of misunderstandings many people have about them.

Like other beans, soybeans have even more protein than other plants. They are also loaded with fiber, iron, magnesium, potassium and zinc. Soy has been shown to help prevent breast cancer, prevent recurrence of breast cancer and increase survival in women with breast cancer. It has also been shown to lower cholesterol and risk of heart disease.

Soy products such as tofu are less apt to cause uncomfortable intestinal gas and bloating than other varieties of beans. (As noted in last week’s column, this issue with other beans tends to resolve after about 14 days of consistent, daily intake.)

The healthiest way to eat soy is by eating organic soybeans (edamame), which can be found in the frozen section of most grocery stores. If you thaw them out, they make a convenient, tasty, healthy snack.

Tempeh is a fermented, unprocessed soy patty and another healthy way to eat soy. Miso is another fermented whole soy food, in the form of a thick paste, and forms the base for miso soup, that is part of the traditional Japanese breakfast. Miso is salty, but the anti-hypertensive effects of the miso seem to outweigh the blood pressure-increasing effect of the salt, according to Dr. Michael Greger (, “How Not to Die” book).

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Another benefit of miso is that it contains probiotic bacteria. Tofu is processed soy, and half of the nutrients are lost in the processing. However, there are so many nutrients to begin with that tofu is still very nutritious. Soy milk is also processed, but if putting a little unsweetened soymilk on your oatmeal every morning makes the oatmeal more tasty, by all means do it.

One of the reasons soy gets a bad rap is that lots of “fake meat” products such as Beyond Chicken Grilled Strips and many veggie burgers are made from soy. In this case the soy is very processed, resulting in loss of most of the nutrients. However if these products keep you from eating meat, dairy and chicken, you’re still better off. These meat alternatives often have the same texture and taste as meat or chicken, but it’s best to break your addiction to these foods and just “get over” the desire to eat them. (I have to admit I enjoy Tofurky at Thanksgiving, and have to fight off the carnivores in my family who want to share it).

The other issue with soy is that Monsanto’s Roundup Ready soybeans are the No. 1 genetically modified crop. It’s not completely clear yet that GMO food itself causes problems in humans (at least GMO food should be labeled, though), but according to Dr. Greger, Roundup and other pesticides even in very small concentrations have estrogenic effects in humans. That means they stimulate the growth of estrogen-receptor-positive breast cancer cells. Roundup Ready GMO soy contains these harmful pesticides, whereas organic soybeans and soy products do not. So when buying soy products you definitely should buy organic.

One of the false beliefs about soy is that because it contains isoflavones, which are weak phytoestrogens (phyto refers to plant), it must cause breast cancer. According to Dr. Greger and other experts, the opposite is true. There are two types of estrogen receptors in the body, alpha and beta, and the effects of soy phytoestrogens on different tissues depend on the ratio of alpha to beta receptors in those tissues. So soy lowers breast cancer risk, which is an anti-estrogen effect, while decreasing hot flashes, which is a pro-estrogen effect.

Is there such a thing as too much soy? The answer is yes. In the daily dozen section of “How Not to Die,” legumes are listed as one of the foods we should be eating daily. Three servings a day of legumes are recommended, and a serving of soy would be a cup of edamame or ½ cup of tofu or tempeh. In Asia, where the breast cancer rate is one-sixth of what it is in the U.S., they eat amounts like that. However, in the U.S. some people eat much larger amounts of soy in the form of tofu, soymilk and fake meat, and this counteracts the benefits of the soy. It’s always better not to eat too much of one thing, because different vegetables have different health-promoting nutrients.

Dr. Feinsinger, who retired from Glenwood Medical Associates after 42 years as a family physician, now has a nonprofit Center For Prevention and Treatment of Disease Through Nutrition. He is available for free consultations about heart attack prevention and any other medical concerns. Call 970-379-5718 for an appointment. For questions about his columns, email him at

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