Few foods are as divisive as soy.
Is it healthy or harmful?
Depends on who you talk to.
© Ryan K Liebe
It’s far from obvious.
Clean-eating and paleo blogs tend to be antisoy; author and part-time vegan Mark Bittman embraces it.
“People went from embracing soy to fearfully avoiding it.”
© Ryan K Liebe
In any case, soy is almost everywhere.
Americans spent $4.5 billion on soy foods in 2013, up from $1 billion in 1996.
Meanwhile, fast-food restaurants like Chipotle are serving up veggie mains like tofusofritas.
So what’s the real storycan soy harm us or heal us?
Then it caught on quickly, and for good reason.
Soy foods are also cholesterol-free and low in saturated fat.
(The Japanese eat around 9 grams a day, versus about 1 gram for Americans.)
Soy products began flying off supermarket shelves.
Meanwhile, soy was getting buzz for another reason: its possible role in preventing cancer.
Those same population studies were showing that Asian women had a fivefold lower breast cancer risk than American women.
Eager to understand why, researchers focused on compounds called isoflavones.
Soybeans are by far the richest source: They have 50 times more isoflavones by weight than split peas.
Could isoflavones also protect humans?
It certainly seemed possible.
Scientists have spent decades trying to understand how isoflavones act inside our bodies.
But generally, after you eat a soy burger, its isoflavones travel from your intestines into your bloodstream.
There, they chemically look a lot like the female hormone estrogen.
But like most nutritional stars, soy soon fell off its pedestal.
At any rate, a 3 percent drop is probably not a big deal.
There was more bad news to come.
Helferich also found that genistein made these tumors less responsive to anticancer drugs like tamoxifen.
Because soy was still such a nutritional darling, Helferich’s findings were initially met with derision.
But with further research, Helferich says, “the tide started to shift.”
Want to read the remainder of this story?
Click below to download the digital issue for the full feature.
Photo Credit: Ryan Liebe
