The sound of soy

Have you ever wondered why the edamame appetizer at sushi restaurants is so expensive? It’s just a small pile of steamed and salted soybeans, still in their pods, and yet can cost $4 to $5.

Soybeans — America’s second-largest cash crop behind corn — are currently selling for 7.7 cents per pound, according to the Chicago Board of Trade. The beans at the sushi bar, relieved of their pods and dried like commodity soybeans, weigh roughly 1/20 of a pound, which would be worth about two-fifths of a cent. Of course, the edamame beans were picked green, frozen, and shipped, all of which add to the cost. But I guarantee the raw materials for edamame are less expensive than the raw materials for a spicy tuna roll, which goes for roughly the same price.

You might suspect price gouging, but I’d suggest it’s related to something else: If you eat too many soybeans, you’ll have enough gas to chase even the dog out of bed.  

That soybeans give you gas isn’t news to most vegetarians — nor their spouses, friends, co-workers, classmates and neighbors. The chief culprits are two soybean oligosaccharides, which we don’t have the enzymes to digest. These indigestible complex sugars slowly ferment in the colon, producing gas. While a small dose of soy will produce relatively benign levels of personal emissions, things tend to blow up, so to speak, as the dosage increases. Therein lies the answer to the edamame question: small portions so you don’t fart your way home, larger price tag to limit your consumption to a few harmless nibbles.

While 45 percent of the world’s soybeans are currently grown in the United States, Brazil is rapidly replacing its forests with soybean plantations, and catching up. Virtually all soybeans are grown by large agribusinesses that find much to love in this crop. First, it’s a legume, which means it manufactures its own nitrogen fertilizer. Soybeans can also be turned into all sorts of value-added products, like paint, plastic, resin, ink, fuel, and clothing. Finally, they’re high in oil, and are the most efficient form of plant protein we can grow, which makes soy good for animal feed and as a meat substitute for vegetarians.

A 1995 study, published in the New England Journal of Medicine and financed by DuPont, presented compelling evidence that soy is good at lowering “bad” cholesterol. That persuaded the FDA to allow the soy industry to claim: “25 grams of soy protein a day, as part of a diet low in saturated fat and cholesterol, may reduce the risk of heart disease.” This correlation, which has done wonders for the popularity of soy products, has been challenged by a growing legion of people and organizations who question whether soy is really that good for you.

Regardless of whether it lowers bad cholesterol, soy isn’t unhealthy. Perhaps the only bad news — aside from the gas — is soy contains high levels of the isoflavanoids genistein and daidzein. These compounds can bind cellular estrogen receptors, which means they can mimic the effect of estrogen in the body.  

While estrogen is important, especially for women, and has been shown to be good for the brain — which might explain why women are so smart — upsetting the body’s balance of the hormone does have drawbacks. Dietary estrogen-like compounds can throw female hormonal cycles out of whack. In men, estrogen-like compounds can reduce testosterone levels and lead to what are medically referred to as “man-boobs.” Then there’s some controversial and contested research by the National Institute of Health suggesting soy-based estrogen-like compounds can disrupt sexual development if given to infants.

While some of this research is far from settled and still up for debate, the one undisputed and more immediate issue is the digestive one. And the soy industry apparently agrees, recently funding studies with names like “Flavor and flatulence factors in soybean protein products” and “Effects of various soybean products on flatulence in the adult man.”

It seems to me that the answer lies in the processing. In China and Japan, where soy has been used for thousands of years, you see it most often in sauces, like hoisin or soy sauce, or miso (which is already fermented). Tofu, which has those difficult-to-digest oligosaccharides removed, is also a common soy source, and like the above sauces much easier to digest.

The exception is soy milk. Although it’s tough to generalize because commercial processors have many ways of making soy milk, it’s generally understood that it will give you gas.

To research this assertion, I bought 39 cents worth of dried, organic soybeans. After soaking them overnight, I rinsed and then blended them with water. I filtered the mixture through a cloth, squeezing out all the liquid, and discarded the bean solids. Then I simmered the milk for 10 minutes, added vanilla and maple syrup, and let it cool. Boy, it was good, perhaps the best soy milk I’ve ever had. I couldn’t stop drinking it, and drank nearly a quart. That night I slept alone. 




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