Soy losing its reputation as a fringe food, growing as nutritional choice for table

Soy, which most Americans once considered the province of vegetarians, the lactose-intolerant and Asian cuisine lovers, is losing its reputation as a fringe food.

Americans' joy for soy has grown so much that consumption doubled between 1997 and 2003, either through whole foods such as tofu and tempeh or through soy isoflavone concentrates added to processed foods including nutrition bars, yogurt and baked goods.

“I think there's a lot of good marketing going on,” says dietitian Mary Beth Kavanagh, a nutrition instructor at Case Western Reserve University. “There's a perception that it's healthier than other foods.”

Soy's reputation as a heart-healthy food increased in recent years after clinical studies showed consumption of at least 25 grams of soy protein per day moderately lowered total and low-density lipoprotein (the “bad” cholesterol).

High cholesterol is a major risk factor for coronary heart disease, which can lead to heart attack.

Some scientists point to soybean components, such as the isoflavones genistein and daidzein, as being responsible for soy's cholesterol-lowering properties.

To eat the 25 grams of soy protein necessary per day to lower cholesterol takes some dedication, however. You would need to drink 3.5 cups of soy milk (7 grams of protein per serving). Or, eat 2.5, half-cup servings of tofu (10 grams of protein per serving).

But even if you don't eat enough soy to improve your heart health, it still is a good choice nutritionally.

Soy is high in good-quality protein and contains all the essential amino acids. It has a healthy balance of carbohydrate and fat and is loaded with vitamins and minerals. To get the full health benefits, eat it in its whole forms: soy milk, tempeh, tofu, roasted soybeans or soy flour.

Processed soy foods, such as hot dogs, chips, burgers and snack bars, are high in protein but typically contain low levels of isoflavones.

“You can't compare them for the benefits,” says Amy LeJeune, a dietician at University Hospitals' Ireland Cancer Center. “It's like adding junk food in some regard.”

If you can't stomach the thought of eating tofu, sorry: Soy isoflavone supplements in food or pill form aren't going to do the job, says an advisory published by the American Heart Association.

That's probably because supplements are absorbed differently from whole foods, LeJeune says.

“Most people want to take a pill and be done with it,” she says. “But there's synergy with food.”