29 July 2013

Is soy safe?

Often I am asked “Are soybeans and their products safe to eat?” It seems some people would have us believe soy is full-on toxic. Others point to the low rates of breast cancer and menopausal difficulties in Asian women, link this to their regular soy consumption and suggest soy is something we would all benefit from.

Wherein lies the truth? Let us go Out on a Limb once more and examine the science behind soy and breast cancer so we can bring some logic and clarity to this often steamy debate. Then I will tell you what Ruth and I actually do, and not shirk from drawing some compelling conclusions and making recommendations.

Also a reminder Meditation in the Desert starts September 6th and we do have a couple of places still available.  LINK HERE. Attached is an amazing aerial shot of the desert taken near to where we go in the Western MacDonnell Ranges. Just like an aboriginal painting. Or is that Fred Williams?! The picture is even more remarkable full screen.


But first

Thought for the day
If information alone could change people, 
Everyone would be skinny, rich and happy.
                                              Les Brown, composer and band leader

Soy products have gained widespread popularity in the West over the last 50 years. The supermarkets are full of them and they are added to so many pre-prepared foods, yet whether they are really safe, and especially what to recommend in regard to breast cancer has been an issue of great contention this last decade. It is an area in which I have taken a great deal of interest. I have read widely, spoken to many authorities and fielded many questions.

What follows then is a major piece in two parts which aims firstly to bring understanding to the soy bean itself. Particularly when it comes to nutrition, I am of the view that if we can understand the principles, then the details follow fairly simply and we will have the confidence to make good choices.

And then next week, how does soy interact with breast cancer? Does it cause or prevent breast cancer? And what of its role for those who have developed breast cancer – does it help or hinder? And what about prostate cancer and our health in general?

As it seems the answers to these questions may well vary depending upon what type of soy foods we eat, let us begin by understanding the bean itself.

THE SOY BEAN (Glycine max)
1. The raw soybean (or soya bean as it is called in the UK) is a legume that originated in East Asia but is now classified as an oilseed rather than a pulse by the FAO. There are 2 main types, those used for eating (which make up about 15% of world production), and those for oil (85%).

Raw soybeans contain trypsin inhibitors that make them toxic to humans and all other animals with a single stomach. Happily, cooking with "wet" heat destroys the enzyme and solves this problem, so all edible forms of soy have been, or need to be cooked.

HINT: Do not sprout soybeans unless you plan to cook them.

2. The traditional use of soybeans fall into 2 categories:
i) Non-fermented foods including tofu, tofu skin and soy milk.

ii) Fermented foods including tamari (traditionally made pure soy sauce), miso (fermented soybean paste), and tempeh. Fermentation does lower the phytoestrogen content found in raw beans. People have claimed that historically soybeans were only used after fermentation, but we shall investigate whether or not this would seem to be a relevant issue.

3. Processed soy products are a more modern phenomena and usually stem from soy flour (made by roasting and grinding the beans) and its products.

One of the most common is TVP (Texturized Vegetable Protein – which also can be made from wheat, oats and cotton seeds). TVP is a de-fatted soy flour product that is a by-product of extracting soy oil. It has a protein content equivalent to that of meat and is often used as a meat substitute or extender.

Fat-free (defatted) soybean meal is a significant and cheap source of protein for animal feeds and many prepackaged meals. It is used widely. Processed soy may be found in many things from vegetable sausages to Mars bars.

SOY BEAN FACTS 

GMO 
In 1997, about 8% of all soybeans cultivated for the commercial market in the United States were genetically modified. In 2010, the figure was 93%. Unless a soy product stipulates that it is GMO free, or organically grown, it is almost certain to contain at least some genetically modified beans.

Soy oil 
Soy beans have a high oil content; around 20%; and soy oil accounts for about 65% of all oil used in commercial and home cooking. However, soy oil is low in Omega 3 fatty acids and high in Omega 6s. The ratio is .13 : 1, whereas flaxseed oil is 3.45 : 1; so for all the reasons why flaxseed oil is good for regular use, soy oil is not.

Tofu usually contains under 10% fat, so the oil type is not a major issue when eating it – unless you have very particular needs.

Soy protein
Soy beans are high in protein: around 38–45%.

Soybeans are an excellent source of complete protein. A complete protein contains in the one food all the essential amino acids in a good balance necessary for human health. Meat is well known as a complete protein and concerns have been raised (probably in a way that is highly overrated) that vegetarians may miss out on some amino acids.

Soy protein has the nutritional equivalent of meat, eggs, and casein for human growth and health. So, as confirmed by the US Food and Drug Administration, soy is a good source of protein for vegetarians and vegans.

Tofu – how it is made 
Soaked soybeans are ground; water is added and boiled.  The pulp is then removed leaving soymilk. Next, a natural mineral coagulant such as calcium sulfate, magnesium chloride, or a mixture of both is added, causing the soymilk to curdle. The curds are removed, placed in a cloth-lined box and varying amounts of pressure applied to form soft, regular, firm or extra firm tofu.

The firmer the tofu, the higher the protein and fat levels.

Silken tofu is made when either calcium sulfate or glucono-delta-lactone is added to a thick, rich soymilk. The mixture is put into a package that is then heated to activate the coagulation and produce the tofu in the package. 

Typically, tofu contains between 10 and 15% protein and 5 to 9% fat.  It is relatively low in carbohydrates and in fibre (as the pulp was removed), making it easy to digest.

Soy production and the environment
Soybeans produce

   . at least twice as much protein per acre compared to most other major vegetables or grains.

   . five to 10 times more protein per acre than land set aside for grazing animals to make milk.

   . up to 15 times more protein per acre than land set aside for meat production.

Environmental groups have reported increased soybean cultivation in Brazil has destroyed huge areas of Amazon rainforest. However, most of the soybeans  grown contribute to livestock fodder and oil production, so there is still great environmental merit in eating less meat and more soybeans.

NEXT WEEK

How is breast cancer affected by oestrogen? Do the phyto-oestrogens (natural, oestrogen-like substances) in soybeans cause breast cancer, protect from it, help or hinder recovering from it? And what of soy and prostate cancer and our health in general?

RELATED BLOG
Eating Well, Being Well

NOTICEBOARD

1. Meditation in the Desert September 6th to 15th


Seven days meditating in one of the world’s best natural meditation environments, followed by several days hanging out with senior local indigenous people. A rare chance to glimpse something of this sadly disappearing, or at least, dramatically changing, traditional culture.


To the right, the view of the Western MacDonnell Ranges from Hamilton Downs where we sit to meditate.


Just a couple of places still available. For enquiries LINK HERE or ring +61 3 59666130

2. Meditation classes in Albury, 6th August 2013
Kaye Ellis is someone I know well and can recommend. Her next meditation course in Albury runs weekly for 6 consecutive weeks beginning on Tuesday 6th August 2013 at 2pm. Each class runs for 1 and a half hours. Kaye does not charge for the courses but asks that if able, participants donate $10 per session which she then gives to the Gawler Foundation.

Details about the course and Kaye’s interest in meditation can be found at meditationalbury.weebly.com. Contact Kaye Ellis: kaye.ellis3@gmail.com

GREAT TED TALK
Your genes are not your fate, with Dean Ornish. To find out how to change your genes, LINK HERE

8 comments:

  1. Love your blog Ian! Thanks for researching this so carefully and getting it clear what some of the issues are. It's the best summary I have read about soy and it is such a subject of confusion and misinformation. Thanks largely to the dairy industry and meat eaters who feel a need to justify their habits.

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    1. I am of the opinion that it is helpful to understand that there is a turf war going on between the dairy and soy industries. One only has to think back a decade or so and remember how hard it was to find any reliable soy products; now every supermarket is full of them, In studying the research, in this field as in most others, it is independent research that we need to be guided by. There are clearly powerful vested interests at work on both sides of this argument.

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  2. Ian this is a really great breakdown of a topic that as you say is confusing to many. One thing I've heard is that fermented soy products are OK but unfermented are not. It sounds like you might be covering this in the next instalment :)

    Thank you for tackling this contentious issue!

    Claire

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    Replies
    1. Thanks for the feedback Claire and the question which is a common one that I hear.
      From all I read and understand, it is not the fermentation that is the issue, but processing. If we eat soy in its traditional forms, and that includes in my definition unfermented forms, then it seems all will be well. We may get real benefits; we almost certainly will get no harm. the more processed soy is, the more problematic the literature tells us it becomes.
      And yes, more on this next week!

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  3. I have been to 3 different doctors asking this question as a soya only person and raising my daughters on soya, I'm very interested in this post. Thanks Lea

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  4. Amazing photos of the desert. The aerial shot looks incredible when blown up. How extraordinary that aboriginals lived in this environment for thousands of years with no mod-cons! I wish I could be going to meet with some of them and maybe learn something.

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