Epidemiological studies have shown that Asians, particularly in Japan and China, have a lower incidence of breast and prostate cancer than people in the United States, and many of these studies credit a traditional diet that includes soy. But Asian diets include small amounts–about nine grams a day–of primarily fermented soy products, such as miso, natto, and tempeh, and some tofu. Fermenting soy creates health-promoting probiotics, the good bacteria our bodies need to maintain digestive and overall wellness. By contrast, in the United States, processed soy food snacks or shakes can contain over 20 grams of non-fermented soy protein in one serving.

‘There is important information on the cancer-protective values of soy,’ says clinical nutritionist Ed Bauman, head of Bauman Clinic in Sebastopol, California, and director of Bauman College. ‘As with any food, it can have benefits in one system and detriments in another. [An individual who is sensitive to it] may have an adverse response to soy. And not all soy is alike.’

‘Soy is not a food that is native to North America or Europe, and you have issues when you move food from one part of the world to another,’ Bauman says. ‘We fare better when we eat according to our ethnicity. Soy is a viable food, but we need to look at how it’s used.’

Once considered a small-scale poverty food, soy exploded onto the American market. Studies–some funded by the industry–promoted soy’s ability to lower disease risk while absolving guilt associated with eating meat. ‘The soy industry has come a long way from when hippies were boiling up the beans,’ says Daniel.

These days the industry has discovered ways to use every part of the bean for profit. Soy oil has become the base for most vegetable oils; soy lecithin, the waste product left over after the soy bean is processed, is used as an emulsifier; soy flour appears in baked and packaged goods; different forms of processed soy protein are added to everything from animal feed to muscle-building protein powders.

Soy protein isolate was invented for use in cardboard,’ Daniel says. ‘It hasn’t actually been approved as a food ingredient.’

Soy is everywhere in our food supply, as the star in cereals and health-promoting foods and hidden in processed foods. Even if you read every label and avoid cardboard boxes, you are likely to find soy in your supplements and vitamins (look out for vitamin E derived from soy oil), in foods such as canned tuna, soups, sauces, breads, meats (injected under poultry skin), and chocolate, and in pet food and body-care products. It hides in tofu dogs under aliases such as textured vegetable protein, hydrolysed vegetable protein, and lecithin–which is troubling, since the processing required to hydrolyse soy protein into vegetable protein produces excitotoxins such as glutamate (think MSG) and aspartate (a component of aspartame), which cause brain-cell death.

Soy also is one of the foods–in addition to wheat, corn, eggs, milk, nuts, and shellfish–most likely to cause allergic reactions. Most people equate food allergies with anaphylaxis, or a severe emergency immune response, but it is possible to have a sub clinical sensitivity, which can lead to health problems over time (and is exacerbated by the lack of variety common in today’s American diet).

‘People can do an empirical food sensitivity test by eliminating the food for a period of time and reintroducing it to see if there’s an immune response, but most don’t do this,’ says Bauman. ‘Genetically modified (GM) soy is the most problematic, and that’s probably what most people are eating if they’re not paying attention. People can develop sensitivity to a food that has antigens or bacteria not originally in the food chain, as is the case with GM foods.’

Yet avoiding GM soy doesn’t mean all is well, Daniel says:

‘One question I get all the time is, ?What if I only eat organic soy?’ The assumption is that GM soy is problematic and organic is fine. Certainly, organic is better, but the bottom line is that soy beans naturally contain plant estrogens, toxins, and anti-nutrients, and you can’t remove those.’

The highest risk is for infants who are fed soy formula.

‘It’s the only thing they’re eating, they’re very small, and they’re at a key stage developmentally,’ says Daniel. ‘The estrogens in soy will affect the hormonal development of these children, and it will certainly affect their growing brains, reproductive systems, and thyroids.’

Soy formula also contains large amounts of manganese, which has been linked to attention deficit disorder and neurotoxicity in infants. The Israeli health ministry recently issued an advisory stating that infants should avoid soy formula altogether.

Anti-nutrients in soy block enzymes needed for digestion, and naturally occur-ring phytates block absorption of essential minerals. This is most worrisome for vegans and vegetarians who eat soy as their main source of protein, and for women in menopause who up their soy intake through supplements.

Soy contains phytochemicals–plant nutrients with disease-fighting activity–called isoflavones. Studies claim isoflavones can mimic the body’s own estrogens, raising a woman’s estrogen levels, which fall after menopause, causing hot flashes and other symptoms. On the other hand, isoflavones may also block the body’s estrogens, which can help reduce high estrogen levels, therefore reducing risk for breast cancer or uterine cancer before menopause. (High estrogen levels have been linked to cancers of the reproductive system in women.)

Although soy’s isoflavones may have an adaptogenic effect (contributing to an estrogen-boosting or -blocking effect where needed), they also have the potential to promote hormone-sensitive cancers in some people. Studies on the effects of isoflavones on human estrogen levels are conflicting, and it’s possible that they affect people differently. In men, soy has been shown to lower testosterone levels and sex drive, according to Daniel.

Bauman believes processed soy foods are problematic but maintains that soy has beneficial hormone-mediating effects.

‘People are largely convenience-driven,’ he says. ‘We’re looking at this whole processed-food convenience market and we’re making generalisations about a plant. Is soy the problem, or is it the handling and packaging and processing of the plant that’s the problem?

‘Primary sources of food are a good thing. Once there was a bean, but then it got cooked and squeezed and the pulp was separated out, and it was heated and processed for better shelf life and mouth feel. Soy milk is second or third level in terms of processing.’

Bauman’s eating-for-health approach calls for a variety of natural and seasonal unprocessed whole foods, including soy in moderation, tailored to individual biochemistry and sensitivities.

‘Using soy as part of a diet can bring relief for peri-menopause, for example,’ he says. ‘Throw out the soy and you throw out the isoflavones.’ (It is possible to obtain plant estrogens to a lesser extent from other foods, such as Lima beans or flax.) ‘The literature is extensive on the benefits of soy, and that should always be stated, just as the hazards should be. That’s science. These studies are not ridiculous or contrived, but take a look at them. Who’s funding them?’ asks Bauman.

‘There are a lot of problems with these studies,’ Daniel says, adding that the 1999 heart health claim was an industry-funded initiative. ‘Even if there is positive information, and even if these studies are well designed, we need to weigh that against the fact that we’ve also got really good studies showing the dangers. Better safe than sorry is the precautionary principle. Possible benefits are far outweighed by proven risks.’

Daniel and Bauman agree on the benefits of variety. ‘My experience as a clinical nutritionist is that people who have a varied diet tend not to get into trouble,’ says Daniel.

‘We like to demonize certain foods in this society,’ says Bauman. ‘If you want to find a fault, you’ll find it. The bottom line is: What is a healthy diet?’

Soy ‘Nuggets’ Tofu
Soy milk, curdled and pressed into cubes of varying firmness. Often used as meat substitute. A non-fermented product, tofu contains anti-nutrients, which can block absorption of essential minerals.

Fermented soy bean paste, used in soups and sauces. Rich in probiotics, good bacteria that aid vitamin absorption. Miso is high in sodium but is considered one of the healthiest soy products.

Soy bean Oil
To extract oil, soy beans are superheated, ground, pressed, mixed with chemicals, and washed in a centrifuge. Soy bean oil accounts for 80 percent of all liquid oils consumed annually in the United States.

Soy Milk
A processed beverage made of ground soy beans mixed with water and boiled, which removes some toxins. Sugar is added to improve flavour. An eight-ounce serving contains up to 35 milligrams of isoflavones, which may change estrogen levels and hormonal function.

Snack Food
Highly processed, a source of trans-fat. Check your labels: Potato chips, tortilla crisps, and many other deep-fried things have been cooked in soy oil–straight up or partially hydrogenated.

Whole soy beans pressed into loaves, which are then fermented. Often used as a meat substitute. Tempeh is rich in B vitamins, minerals, and omega-3 fatty acids.

Fast Food
A source of hidden soy. Processed soy proteins extend some burgers and chicken (nuggets, patties, even ‘grilled breasts’). Buns contain soy oil and to a lesser extent soy flour and lecithin. Soy oil also appears in dressings and dips, in American ‘cheese,’ and as the No. 2 ingredient in fries. There’s even soy in Big Mac’s secret sauce: Soy bean oil nets top billing.

Whole soy beans, commonly boiled in the pod and eaten as a snack. Most commercial edamame has been preheated to make digestion easier, but it still contains anti-nutrients.

How Much Soy Is Too Much?

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 soy bean 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 hospitalised 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, paediatricians, 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?

That’s the next step.  The first 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 going to petition the FDA to remove the GRAS [generally recognised 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 labelling will ever be a reality?
We’re hopeful that the petitions out there will work, but its also good to bring 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.