How Much Is Too Much?

Clinical nutritionist Kaayla Daniel on the Dos and Don'ts of soy consumption

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Editor's Note: Kaayla Daniel is a certified clinical nutritionist with a Ph.D. in nutritional sciences and anti-aging therapies from the Union Institute and University of Cincinnati, Ohio. She is the author of The Whole Soy Story: The Dark Side of America's Favorite Health Food (New Trends, 2005).

What health problems do you see in your practice that can be traced back to overconsumption of soy?
I work mostly with midlife women, and they're likely to eat a lot of soy and drink a lot of soy milk. They're taking soy isoflavone supplements because they've heard that it's going to help them through menopause. A lot of these women are very intelligent and educated, and, unfortunately, they get this idea that if a little of something might be good, then they should do a lot of it. They start gaining weight, feeling fatigued; they get lethargic and depressed, and when they go to a regular doctor, they're told 'Well, what do you expect, you're getting old,' and that this is typical of menopause. In fact, the symptoms are almost entirely coming from that change in their diet, which had to do with soy.

How much soy does the average person consume in a day?
Someone on a junk-food diet is getting soy flour in the fast-food hamburger bun, soy protein in the burger itself, and soy oil in the fries; soy is in every one of these products because it's cheap and abundant. You'll find soy hidden in so many foods, and small quantities add up.

People often start by drinking a lot of soy milk. If they are taking supplements, they can be getting really high doses. Even scientists working for the soy industry will say they support soy food but do not support use of soy supplements. It is so dangerous at such a high level, and it's harming many people.

How does marketing affect soy consumption?
It's very much about marketing. If we look back, the soybean was used in this country for soy oil. They take apart the bean and take out the oil and turn it into margarines and shortenings and all those liquid vegetable oils. Once the oil is out, what they had left over was a whole lot of protein.

What's happened is that some of the things they tried to get rid of they're now marketing as things that can prevent cancer or prevent problems. They take something that's bad and turn it into something that's good. Every time they remove a component of soy, they have another thing they can sell.

In Kenya, the soy industry is talking to bakers, teaching them to use soy flour in baked goods, and down in Johannesburg they're working on using soy protein shake powders to help AIDS patients. When the tsunami hit [in 2004], the soy industry was right there giving people assistance and free soy products. Rather than helping people pick up the pieces and get their small farms back together, they're replacing local foods with something that's global.

Which soy product is the worst?
The biggest problem is soy milk. Those with lactose intolerance think that soy milk is a great alternative, and they're drinking a lot and getting a huge dose of isoflavones. If you're drinking soy milk, you're going to have a problem, or most people will sooner or later. We're all different--some people will start having problems in a day, and some people will think they're fine and a year later things will start to go downhill.

Drinking just one glass a day of soy milk will give someone the level of plant estrogens that has hurt the thyroids of healthy Japanese men and women. Most people are drinking several glasses, plus the soy protein energy bars and the bags of edamame.

If people are concerned about getting enough calcium, try a homemade coconut tonic made with coconut milk and dolomite powder. It will match the mineral content of milk and support the immune system and thyroid.

What provoked the Israeli health ministry warning on soy foods?
The Israeli health ministry issued an advisory saying that babies should not get soy formula and that children under 18 should eat soy no more than once a day, three times a week maximum. Adults should exercise caution due to the adverse effects on fertility and increased breast cancer risk.

It started a few years ago when several babies were hospitalized with severe beriberi and brain damage because of a soy infant formula that was deficient in vitamin B1. The manufacturer had gotten the idea that if soy is such a perfect food, already high in B vitamins, why should they add extra B vitamins? They didn't understand that babies need added B1 and that processing affects vitamins. National alerts were issued, the product was recalled, and all the babies on soy formula immediately got injections of B1.

That incident caused the Israeli health ministry to start looking into soy formula. They formed a committee including toxicologists, oncologists, pediatricians, and other experts, they reviewed literature, and they decided there are some risks. The Israeli soy industry has protested mightily and threatened to sue the government, but the health ministry maintained its position.

How much soy is OK?
I'll use the numbers the Israelis used. But, of course, some people are allergic to soy, some are sensitive to soy, some have thyroid problems already. Those people should probably avoid it. Then there's the issue of what types of soy we're talking about. I still enjoy miso soup.

Do you think we should have a warning label here in the United States?

That's the next step. I will be involved with three petitions to the Food and Drug Administration (FDA). The first will petition to remove from labels the current health claim that soy prevents heart disease. It's been on foods since November 1999, and soy food sales went from less than $1 billion to $4 billion [annually] between 1999 and 2004. [In 2006] the American Heart Association retracted its position on soy. They're now saying that soy does not prevent heart disease or lower cholesterol. Second, we're going to petition the FDA to remove the GRAS [generally recognized as safe] status for soy protein isolate. The third petition will have to do with putting warning labels on soy foods.

Do you think that labeling will ever be a reality?
We're hopeful that our petitions will work, but we're also bringing attention to the issues. What amazes me is that so many vegetarians and vegans will say that the FDA would never have approved a 'soy prevents heart disease' claim unless there was good strong evidence. Hello! This is the same FDA that gave us Vioxx and aspartame. I'm sure in Berkeley in the '60s there were little companies that made tofu and soy milk, and people still believe that soy is that kind of food. What they're not getting is that we have Big Pharma, and now we have Big Soy.


Excerpted from Terrain (Spring 2007). Subscriptions: $15/yr. (3 issues) from 2530 San Pablo Ave., Berkeley, CA 94702; www.ecologycenter.org/terrain.


Want more? Read the rest of Utne Reader's July/August package on the secrets of soy:

  • The Dark Side of Soy
    Is America's favorite health food making us sick?
    by Mary Vance, from Terrain
  • Whole New Diet
    A health-savvy cookbook shows how to get away from processed foods
    by Julie Hanus
  • Biofuel's Big Bean
    How large-scale soy is threatening the environment and a South American way of life
    by April Howard and Benjamin Dangl, from In These Times