Soy protein isolate - what's wrong?

What's wrong with soy protein isolate, a person once asked on a vegan forum. He knew that "some people don't think it's healthy" but could not understand why.

The first few reponses were all in praise of the substance. "No fat, no fibre, but best of all no need to cook it..." one person wrote. Another added that he / she had been taking soy protein isolate every morning - as a soy smoothie - for a few months and had not experienced any problems.

Then someone posted a YouTube video by Dr John McDougall, a medical doctor and author of several health books that advocate a vegetarian / vegan diet, which, for many people, would include fair amounts of soy products.

The discussion took a dramatic U-turn. The next person wrote: "Wow. Interesting stuff. That's me not taking it again." The one after had just one word to express disappointment: "Rats."

So what did Dr John McDougall say? For the most part of his lecture, he was actually talking about the harm of cow's milk and other dairy products.

He talked about Insulin-like Growth Factor 1 (IGF-1), a powerful growth hormone and noted that it is associated with shorter lifespans. For example, small animals and small-built people (I think of ex-Chinese leader Deng Xiaoping) tend to lead longer lives.

Dr John McDougall further pointed out that IGF-1 promotes ALL forms of growth, including the growth of cancer cells. He cited scientific studies that showed dairy protein increased IGF-1 activity in the body much more than, say, meat protein.

Then came the shocker. Near the end of his lecture, Dr John McDougall presented scientific evidence that soy protein isolate was twice as powerful as milk protein in increasing IGF-1 activity. As little as 40 grams of this soy protein increases IGF-1 activity by 69 percent, compared with 36 percent from an equivalent amount of milk protein.

How much is 40 grams? Not much. It might come from one soy-based "chicken" patty and two soy burgers, or one soy candy bar and a glass of soy "milkshake". These are commonly regarded as "healthy foods". Dr John McDougall had himself eaten such foods regularly in the past. He realised his mistake and is now telling others not to repeat it.

The above incidents show how people can ignorant and easily misguided people can be. The few people who initially responded to the forum question simply assumed that soy protein isolate is healthy and safe - just because they had been taking it for a few months without adverse effects.

Back in the 1990s, when I first discovered textured vegetable protein (TVP) - which is made from soy flour and soy concentrate, products similar to soy protein isolate - I also just assumed that it is healthy. After all it is a vegetarian product and the thought that a vegetarian food might be unhealthy never crossed my mind.

I did not question. Even a learned doctor and health writer like Dr John McDougall also initially did not question. So let's ask a few questions, like:

• What is soy protein isolate?
• How is it made?
• Why is it made and what is it used for?

Some of the answers may surprise you!

An industrial (waste) product

Soy protein isolate is described (in a Wikipedia article) as "a highly refined or purified form of soy protein with a minimum protein content of 90 percent on a moisture-free basis."

The fact that it is highly refined should already raise alarm bells. Experience tells us that highly refined foods, like refined sugar and refined sea salt, tend to be harmful to health. In nature, no food is highly refined.

No natural food is pure either. It is not natural and not healthy to eat pure protein. Yet many people do so - in the form of protein powders by bodybuilders, athletes and those attempting to lose weight, as well as in the form of egg whites without the yolks by people who are afraid of cholesterol. Food is not meant to be eaten this way!

When you learn about how and why soy protein isolate, you will have more reasons not to eat it. The manufacturing process is highly industrial and this is not something you can produce in your kitchen:

• The basic raw material is de-fatted soy beans - that is, soy beans with the oils removed for the production of soybean oil. So this is actually made from the waste product of soybean oil production.
• The beans are soaked in an alkaline solution to remove fibre
• The mixture is then separated with an acid wash. This usually takes place in an aluminium container and it leaches toxic aluminium into the final product.
• Finally it is neutralised in alkaline again.
• The process results in a curd, which is then spray dried at high temperatures to produce a dry protein powder.
• In the manufacture of textured vegetable protein, a "fake meat", both high temperature and high pressure are used to extrude the curd.

The very high temperature process removes most, but not all, of the trypsin inhibitors in soy protein. Unfortunately, it also alters the nature of some proteins and forms toxic by-products. Finally, chemical additives are introduced to remove the "beany" flavour and improve taste.

Uses of soy protein

More interesting are the reasons why soy protein was manufactured in the first place - to extract commercial value out of the waste product from making soybean oil.

The manufacturing process was developed in 1936. Initially, the industrial soy protein was inedible and used for, among other things, paper manufacturing and the production of fire-fighting foam. It was only in 1959 that food-grade soy protein because available. This was used as a cheap filler for meat products like hamburger patties and sausages, so that they could maintain high protein levels while using less meat to reduce costs.

Over the years, the use of soy protein isolate expanded. Then in 1988, the US Food and Drug Administration allowed a health claim that soy protein could protect against heart disease. And so, from being just an ingredient for manufacturing meat products cheaply, soy protein became marketed direcly as a "health product" as well.

Today, apart from being used to adulterate foods, soy protein isolate is also used in products such as:

• protein powders and other "health drinks" for muscle buidling, weight loss and other objectives
• infant soy forumla
• soy milk
• soy "meats" like vegetarian burgers and soy sausages
• "health" or "energy" snack bars
• soy cheese
• soy desserts like pudding and "ice-cream".

Many of these are being marketed as "health foods" and many supposedly health-conscious consumers are taking this highly artifical food in the mistaken belief that it is healthy.

Only a small group of health writers are warning against the dangers of these modern soy foods. Particularly active in their campaign against soy are Sally Fallon and Dr Mary Enig of the Weston Price Foundation, an organisation that promotes the value of traditional diets.

Slly Fallon and Dr Mary Enig have been so vacal against modern soy foods that they are sometimes labelled "anti-soy campaigners". But if you read their writings carefully, you will realise that they are NOT against soy per se. They have no issues with of fermented soy products such as miso, natto, soy sauce and tempeh.

They also have no quarrels with non-fermented soy foods like tofu and soymilk, provided they are made the traditional way and consumed the traditional way, in small amounts as side dishes. They are only against the high consumption of modern, unnatural soy foods.

They are not alone. As noted above, even health writers like Dr John McDougall, who in the past ate and recommended soy foods, have begun to warn against the dangers of soy foods, especially soy protein isolate.

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