Is soy safe? – part 2

As you tuck into a delightful tofu and veggie stir-fry, or maybe even some tofu ice-cream, is there a lingering doubt? Is this really doing me good? Am I contributing to the prevention of breast and prostate cancer, or am I, as some would have us believe, contributing to their increased likelihood?

If so, you need the answer to this question: Do the phyto-oestrogens in soybeans act like oestrogen or Tamoxifen? Need a full explanation? Let us go Out on a Limb again, follow on from the earlier post this week where we explored the soybean itself, and using the evidence-base available, explore how cancer and soy beans interact, but first




Thought for the day


The doctor of the future will give no medicine,
But will instruct his patient in the care of the human frame,
In diet and in the cause and prevention of disease

                    Thomas Edison, 1902



WHY LINK SOY and BREAST CANCER?
1. There are historically low breast cancer incidence rates in Asia, where traditional soyfoods are a staple.

2. Research demonstrates isoflavones in soy may exert anti-oestrogenic effects.

3. Some epidemiologic data shows a higher soy intake results in a lower breast cancer risk.

4. Rodent studies demonstrate soy protects against carcinogen-induced mammary cancer.

HOW BREAST CANCER is AFFECTED by OESTROGEN
In broad terms, there are 2 types of breast cancer; oestrogen positive and oestrogen negative. Our discussion relates to oestrogen positive cancers in particular and these make up about 70% of all breast cancers.

Oestrogen positive cancers are aggravated by oestrogen (the main female sex hormone). How this happens is that on the surface of oestrogen positive cancer cells there are receptors for oestrogen. When an oestrogen molecule comes into proximity with such a receptor, it attaches (but does not go into the cell) and creates a cascade of reactions within the cell that speeds up the cancer’s progression.

In earlier times, removal of the ovaries was attempted as a way to reduce oestrogen levels in women with breast cancer. But oestrogen is made in other parts of the body, so only in exceptional circumstances has this proven useful.

Many people will have heard of tamoxifen. This was heralded as a breakthrough drug as, while it does attach to the oestrogen receptors, it does not cause the internal reaction. Therefore, tamoxifen blocks natural oestrogen from having its adverse affects.

Unfortunately, tamoxifen does aggravate uterine tissue and is associated with increased uterine cancer, but on balance it remains a widely used anti-cancer drug. Simply put, tamoxifen is an oestrogen antagonist.


WHAT OESTROGEN IS IN SOY?

There are 3 main oestrogen-like chemicals in soybeans; genistein, daidzein, and glycitein.

They are present in their beta glycoside forms: genistin, daidzin, and glycitin, hence you may see them written differently.

Genistin/genistein, daidzin/daidzein, and glycitin/glycitein account for approximately 50–55%, 40–45%, and 5–10% of total isoflavone content, respectively in soybeans.

Older adults in Japan and Shanghai, China, typically consume between 25 and 50 mg/day of isoflavones and probably no more than 5% of these populations consume more than 100 mg/day. In contrast, people in the United States and Europe consume an average of less than 3 mg/day.

Isoflavones have a chemical structure similar to human oestrogen but bind to estrogen receptors more weakly. Significantly, it has been suggested that genistein, which is the best-studied isoflavone, along with the other isoflavones may act like tamoxifen as estrogen receptor blockers.

What has also drawn attention in recent years are conflicting concerns that isoflavones may stimulate the growth of existing estrogen-sensitive breast tumors. These concerns are based on evidence gathered from studies involving tissue cultures and rodents. However, they do contrast with the human epidemiological evidence that shows among Asian women higher soy intake is associated with a nearly one-third reduction in breast cancer risk and that Japanese breast cancer patients, in comparison to Western women, exhibit better survival rates even after controlling for stage of diagnosis.

SOY for the PREVENTION of BREAST CANCER



In Asia, isoflavones are consumed as traditional soy foods and not in pure or processed forms. Epidemiological data associates lifetime, and particularly pre-adolescent consumption of traditional soy with a decreased risk of breast cancer development in humans.

An Asian-American study on soy found that women, pre- and postmenopausal, who consumed tofu, had a 15% reduced risk of breast cancer with each additional serving per week.

Wu AH, Ziegler, et al. Tofu and risk of breast cancer in Asian- Americans. Cancer Epidemiol Biomarkers Prev. 1996;5(11):901-906.


Another trial reported that women in the highest tertile intake of tofu had a 51% decrease risk of premenopausal breast cancer when compared with women in the lowest tertile. In this study, no statistical significant association was observed between soy intake and breast cancer risk among postmenopausal women.

Hirose K, Imaeda N, Tokudome Y, Goto C, Wakai K, Matsuo K, et al. Soybean products and reduction of breast cancer risk: a case-control study in Japan. Br J Cancer 2005;93(1):15-22.

Messina and colleagues published a major review on this subject in 2008 and I consider it to be one of the very the best review articles on this topic. To quote:

The conclusion drawn from this extensive review of the available literature is that currently there is little evidence to suggest that any potential weak estrogenic effects of dietary isoflavones have a clinically relevant impact on breast tissue in healthy women. Limited data suggest this is also the case for breast cancer survivors.

This evidence includes multiple trials showing no effects on breast proliferation or mammographic density and considerable epidemiologic data showing either no effect or a modest protective role of soy/isoflavone intake on breast cancer risk.

Based on this evidence it seems unlikely that isoflavone consumption at dietary levels (i.e. <100 mg/day) elicits adverse breast cancer-promoting effects in healthy women or breast cancer survivors not undergoing active treatment.

Messina MJ and Wood CE; Nutrition Journal 2008.  To read in full, CLICK HERE http://www.nutritionj.com/content/7/1/17

SOY and its AFFECTS on BREAST CANCER
When this article was first posted in 2008, there was no data to support the notion that soyfoods or isoflavone supplements could improve the survival of breast cancer patients.

Several earlier studies suggested that whole soy foods appeared to have no negative or positive effect on breast cancer. For example the following two studies found soy foods had no negative impact on breast cancer survival.

Boyapati SM, et al. Soyfood intake and breast cancer survival: a followup of the Shanghai Breast Cancer Study. Breast Cancer Res Treat. 2005;92(1):11-17.

Nishio K, et al. Consumption of soy foods and the risk of breast cancer: findings from the Japan Collaborative Cohort (JACC) Study. Cancer Causes Control. 2007;18(8):801-808.
This, and other evidence, prompted Messina and colleagues in their 2008 review quoted above to state:

Available data on breast cancer recurrence and mortality provide some assurance for breast cancer patients that soyfoods/isoflavone supplements, when taken at dietary levels, do not contribute to recurrence rates although more data are clearly needed to better address this issue.

However, in 2009, following more analysis of the Shanghai study, strong new evidence was published showing significant benefits of consuming soy for women with breast cancer in terms of better survival and less cancer recurrence, making Messina’s claim outdated.

Women consuming soy in the highest quartile had a 29% lower death rate over the 4 year follow up, and 32% reduced risk of recurrence. The protective effect was present regardless of oestrogen receptor status of the cancer, or whether tamoxifen was used or not.

This study provided the most compelling evidence to date of a benefit for soy consumption by women with breast cancer (as opposed to no harm). It is important because it shows a benefit for increased soy consumption irrespective of oestrogen receptor status or tamoxifen use.

Shu XO et al. Soy food intake and breast cancer survival; JAMA. 2009 Dec 9; 302(22):2437-43.

The trend of this study was confirmed in 2013 when another study demonstrated soy food intake is associated with longer survival and low recurrence among breast cancer patients.

Zhang, Y.F., et al., Positive effects of soy isoflavone food on survival of breast cancer patients in China. Asian Pac J Cancer Prev, 2012. 13(2): p. 479-482.

More recently still, a major review from the World Cancer Research Fund International’s Continuous Update Project Report: Diet, Nutrition, Physical Activity, and Breast Cancer Survivors has examined a total of 85 studies involving 164,416 women. Included has been analysis of specific evidence related to soy and its interaction with breast cancer.

This major study makes modest conclusions The evidence was sparse and generally consistent, and is suggestive of an inverse relationship between consumption of foods containing soy and all cause mortality. 

Translation? From what solid evidence there is so far, it seems that soy is likely to be helpful; the evidence for it being unhelpful is not there. Conclusion? It is coming after a few more pieces of the puzzle are put into place!


BEWARE:  NATURAL SOY, PROCESSED SOY – DIFFERENT OUTCOMES
It may be that the non-traditional soy foods do create problems. Significantly, soy protein isolates do not contain many of the bioactive components present in whole soy. As we clarified in Part 1, refined products include soy flour and its processed derivatives.


Research has demonstrated that soy protein isolates (85–90% soy protein) do stimulate the growth of

estrogen-dependent tumors. Another study evaluated the relative effects of different degrees of soy processing on the growth of pre-existing tumors and demonstrated that consumption of isoflavones in increasingly purer or more highly enriched forms may have a proportionally worse effect on estrogen-dependent tumor growth.


Allred CD,et al. Soy processing influences growth of estrogen-dependent breast cancer tumors. Carcinogenesis 2004;25:1649-1657.

Some research has shown that soy processing increases breast cancer growth in mice. This may be related to isoflavone metabolism and bioavailability, but more research is needed.

Allred CD, et al. Soy processing influences growth of estrogen-dependent breast cancer tumors. Carcinogenesis 2004;25:1649-1657.

SOY AND TAMOXIFEN
There has also been some concern expressed that soy products may actually interfere with the action of tamoxifen itself. However, recent studies examining the interaction between soy and tamoxifen have yielded neutral or beneficial findings.

In one study, soy intake had no effect on levels of tamoxifen or its metabolites.

Wu AH, et al. Tamoxifen, soy, and lifestyle factors in Asian American women with breast cancer. J Clin Oncol. 2007;25(21):3024-3030.

In another, the combination of tamoxifen and genistein inhibited the growth of human breast cancer cells in a synergistic manner in vitro.

Mai Z, et al. Genistein sensitizes inhibitory effect of tamoxifen on the growth of estrogen receptor- positive and HER2-overexpressing human breast cancer cells. Mol Carcinog. 2007;46(7):534-542.

SOY and CHEMO
One study reported that soy’s main phyto-oestrogen genistein, enhanced the cytotoxic effect of the chemotherapeutic agent adriamycin at low doses against the human breast cancer cell. This enhancing effect was mainly attributed to the increase of necrotic-like, rather than apoptotic, cell death.

Satoh H, Nishikawa K, Suzuki K, et al. Genistein, a soy isoflavone, enhances necrotic-like cell death in a breast cancer cell treated with a chemotherapeutic agent. Res Commun Mol Pathol Pharmacol.2003;113–114:149–158.

SOY and YOUNG GIRLS
Of great interest is research that demonstrates eating soy foods during childhood and adolescence in women, and before puberty onset in animals, appears to significantly reduce the risk of breast cancer later in life.

SYNERGISTIC EFFECTS OF SOY
Research evidence indicates a possible synergistic relationship between soy and green tea consumption.

SOY AND THE AUTHORITIES
The American Cancer Society in 2006 concluded that breast cancer patients can safely consume up to three servings of traditional soyfoods per day, although the group advised against the use of more concentrated sources of isoflavones such as powders and supplements.

The United States Health and Human Services Agency for Healthcare Research and Quality (AHRQ) conducted a review of the available studies and found little evidence of substantial health improvements and no adverse effects, but also noted that there was no long-term safety data on estrogenic effects from soy consumption.

The AHRQ report notes that future studies of the health effects of soy need to better address the complex relationship between health and food components, including how variations in the diets, lifestyles, and health of participants might affect the results.

Also, studies that substitute practical amounts of soy products into people's diets would better address the question of whether people should make the effort to include more soy in their diet.

The Cancer Council of New South Wales released a statement saying scientific research suggests that overall the moderate consumption of soy products does not appear to present a risk to women with breast cancer, and there is equivocal evidence that consuming large amounts of soy products may have a protective effect against developing breast and prostate cancer. However, the Council does not recommend taking soy dietary supplements as there is no evidence they are either effective or safe at preventing or treating cancers.

WHAT RUTH and I DO
We regularly eat organic tofu and soy yoghurt (which Ruth makes from Bonsoy). Ruth drinks small amounts of soymilk (mostly Bonsoy in teas), but I do not – I do not like it and have teas and dandelion coffee black). We eat some tempeh but only have silken tofu by mistake when eating out!

We avoid processed soy products and read labels to avoid the myriad of foods with these products added to them.

MY OWN CONCLUSIONS and RECOMMENDATIONS
In answer to the key question, I conclude the phyto-oestrogens in soy act like tamoxifen, not like oestrogen. I also conclude:
1. Traditional soy foods are almost certainly safe and warrant being a part of a healthy diet for healthy people. I recommend them. I particularly recommend regular soy consumption for young and adolescent girls; but then lifetime consumption seems ideal.

2. Processed or refined or concentrated soy products run the real risk of being problematic for everyone. I do not recommend them.

3. For women with breast cancer, the best evidence currently available suggests traditional soy foods, eaten in traditional amounts are likely to be safe and may well be helpful in reducing recurrences and extending survival. I recommend them.

RELATED BLOGS
Coconut oil – are you nuts?

Food for life – what to eat when

RESOURCES
You Can Conquer Cancer – the revised edition has many other explanations like this one on soy. What type of protein and how much? Which are the best fats to eat and to avoid, and so on. This book is about prevention and long-term good health, as well as cancer recovery.

NOTICEBOARD
Ruth and I leave this week to present our final meditation retreat for the year, Meditation Under the Long White Cloud at Mana retreat centre amidst the peace and beauty of the Coromandel Peninsula in New Zealand.

Then we travel down south to the exquisite landscape at Wanaka to present the 5 day cancer residential program, Mind, Meditation and Healing from November 10 - 14. It will be a delight to be back in New Zealand once more.

Is soy safe?

Major new research has been published regarding soy. Posting this new evidence on my Facebook page has led to a great discussion and revealed that soy still polarizes people. What is the truth?

Will soy give you breast cancer or protect you? Will soy produce breasts in young boys? Protect girls from ever increasingly early onset of puberty? Does it speed up breast cancer, or make a useful contribution to both preventing and recovering from it? Does it really protect from difficulties during menopause?

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.

So this is to revisit an earlier post on these matters that was evidence-based. To re-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 3 compelling conclusions and making recommendations, but first

Thought for the day 
Meditation (reflection) first purifies its own source, ie, the soul, from which it arises.
Then it regulates the inclinations, directs activity, moderates excess, shapes morals, 
Makes life honest and regulated, 
And mediates knowledge of divine as well as human things.

It is this which replaces confusion with order, 
Checks the inclination to lose oneself in uncertainty, 
Gathers together that which is dispersed, 
Penetrates into that which is hidden, 
Discovers that which is true and distinguishes it from that which merely appears as such, 
And brings to light fiction and lie.
                    St Bernard of Clairvaux

Soy products have gained widespread popularity in the West over the last 50 years. But 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 I have taken a great deal of interest in. I have read widely, spoken to many authorities and fielded many questions.

What follows then is a major piece that is evidence-based and comes in two parts, much of which first appeared on this blog in July and August of 2013, and now seems to warrant a re-run. This is the first blog I have repeated, albeit with some important research updates since one year ago.

The aim is firstly to bring further 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 in Part 2, 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?

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 range of options available.

THE SOY BEAN (Glycine max)  

3 Forms – raw, traditional, processed

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 monogastric (single stomached) animals.

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.

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

ii) Fermented foods including soy sauce, miso (fermented soybean paste), and tempeh.

Fermentation does lower the phytoestrogen content found in the raw beans. People have claimed that historically soybeans were only used after fermentation, and 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 – a similar form of which 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 equal 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.

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 of Omega 3 to 6 in soy oil is only .13 : 1, whereas in flaxseed oil it is 3.45 : 1; so for all the nutritional 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 over rated) that vegetarians may miss out on some amino acids.

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

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 sulphate, magnesium chloride, or a mixture of both is added, leading to the soymilk curdling. The curds are removed, placed in cloth-lined forming boxes 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 sulphate 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 fiber (as the pulp was removed), making it easy to digest.

Soy production and the environment

Soybeans produce
1. At least twice as much protein per acre compared to most other major vegetables or grains.

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

3. 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 produced in this area are actually grown for livestock fodder and oil production.

Conclusion?  There is great environmental merit in eating less meat and more soybeans.

STILL TO COME
The burning question – what impact does soy have on breast cancer? How is breast cancer actually affected by oestrogen? Do the phyto-oestrogens (natural, oestrogen-like substances) in soybeans cause breast cancer, or do they protect from it? Does soy help or hinder in recovering from breast cancer?

Part 2 will be posted Thursday

RELATED BLOG
Eating Well, Being Well

RESOURCES
You Can Conquer Cancer – the revised edition has many other explanations like this one on soy. What type of protein and how much? Which are the best fats to eat and to avoid, and so on. This book is about prevention and long-term good health, as well as cancer recovery.

NOTICEBOARD
Ruth and I leave this week to present our final meditation retreat for the year, Meditation Under the Long White Cloud at Mana retreat centre amidst the peace and beauty of the Coromandel Peninsula in New Zealand.

Then we travel down south to the exquisite landscape at Wanaka to present the 5 day cancer residential program, Mind, Meditation and Healing from November 10 - 14. It will be a delight to be back in New Zealand once more.

Ian Gawler Blog: Is soy safe? – part 2

Please note: This blog has been re-posted as there were some technical issues in the original post.

As you tuck into a delightful tofu and veggie stir-fry, or maybe even some tofu ice-cream, is there a lingering doubt? Is this really doing me good? Am I contributing to the prevention of breast and prostate cancer, or am I, as some would have us believe, contributing to their increased likelihood?

If so, you need the answer to this question: Do the phyto-oestrogens in soybeans act like oestrogen or Tamoxifen? Need a full explanation? Let us go Out on a Limb once again, follow on from last week’s exploration of the soybean itself, and explore how cancer and soy beans interact.



Then news of my next workshop; this time in one of Mt Macedon’s most beautiful estates, complete with a gorgeous garden. Duneira on Saturday August 24th. But first




Thought for the day
The doctor of the future will give no medicine, 
But will instruct his patient in the care of the human frame, 
In diet and in the cause and prevention of disease.
                                         Thomas Edison, 1902




WHY LINK SOY and BREAST CANCER?
1. There are historically low breast cancer incidence rates in Asia, where traditional soyfoods are a staple.

2. Research demonstrates isoflavones in soy may exert anti-oestrogenic effects.

3. Some epidemiologic data shows a higher soy intake results in a lower breast cancer risk.

4. Rodent studies demonstrate soy protects against carcinogen-induced mammary cancer.

HOW BREAST CANCER IS EFFECTED BY OESTROGEN
In broad terms, there are 2 types of breast cancer; oestrogen positive and oestrogen negative. Our discussion relates to oestrogen positive cancers in particular and these make up about 70% of all breast cancers.

Oestrogen positive cancers are aggravated by oestrogen (the main female sex hormone). How this happens is that on the surface of oestrogen positive cancer cells there are receptors for oestrogen. When an oestrogen molecule comes into proximity with such a receptor, it attaches (but does not go into the cell) and creates a cascade of reactions within the cell that speeds up the cancer’s progression.

In earlier times, removal of the ovaries was attempted as a way to reduce oestrogen levels in women with breast cancer. But oestrogen is made in other parts of the body, so only in exceptional circumstances has this proven useful.

Many people will have heard of tamoxifen. This was heralded as a breakthrough drug as it attaches to the oestrogen receptors, but does not cause the internal reaction and so blocks the effects of oestrogen. Unfortunately, it does aggravate uterine tissue and is associated with increased uterine cancer, but on balance it remains a widely used anti-cancer drug. Simply put, tamoxifen is an oestrogen antagonist.

WHAT OESTROGEN IS IN SOY?
There are 3 main oestrogen-like chemicals in soybeans; genistein, daidzein, and glycitein. They are present in their beta glycoside forms: genistin, daidzin, and glycitin, hence you may see them written differently.

Genistin/genistein, daidzin/daidzein, and glycitin/glycitein account for approximately 50–55%, 40–45%, and 5–10% of total isoflavone content, respectively in soybeans.

Older adults in Japan and Shanghai, China, typically consume between 25 and 50 mg/day of isoflavones and probably no more than 5% of these populations consume more than 100 mg/day. In contrast, people in the United States and Europe consume an average of less than3 mg/day.

Isoflavones have a chemical structure similar to human oestrogen but bind to estrogen receptors more weakly. Significantly, it has been suggested that genistein, which is the best-studied isoflavone, along with the other isoflavones may act like tamoxifen as estrogen receptor blockers.

What has also drawn attention in recent years are conflicting concerns that isoflavones may stimulate the growth of existing estrogen-sensitive breast tumors. These concerns are based on evidence gathered from studies involving tissue cultures and rodents. However, they do contrast with the human epidemiological evidence that shows among Asian women higher soy intake is associated with a nearly one-third reduction in breast cancer risk and that Japanese breast cancer patients, in comparison to Western women, exhibit better survival rates even after controlling for stage of diagnosis.

SOY FOR THE PREVENTION OF BREAST CANCER
In Asia, isoflavones are consumed as traditional soy foods and not in pure or enriched forms. Epidemiological data associates lifetime, and particularly pre-adolescent consumption of traditional soy with a decreased risk of breast cancer development in humans.

An Asian-American study on soy found that women, pre- and postmenopausal, who consumed tofu, had a 15% reduced risk of breast cancer with each additional serving per week.

Wu AH, Ziegler, et al. Tofu and risk of breast cancer in Asian- Americans. Cancer Epidemiol Biomarkers Prev. 1996;5(11):901-906.

Another trial reported that women in the highest tertile intake of tofu had a 51% decrease risk of premenopausal breast cancer when compared with women in the lowest tertile. In this study, no statistical significant association was observed between soy intake and breast cancer risk among postmenopausal women.

Hirose K, Imaeda N, Tokudome Y, Goto C, Wakai K, Matsuo K, et al. Soybean products and reduction of breast cancer risk: a case-control study in Japan. Br J Cancer 2005;93(1):15-22.

Messina and colleagues published a major review on this subject in 2008 and here I quote from what I consider to be one of the very the best review articles on this topic:

The conclusion drawn from this extensive review of the available literature is that currently there is little evidence to suggest that any potential weak estrogenic effects of dietary isoflavones have a clinically relevant impact on breast tissue in healthy women. Limited data suggest this is also the case for breast cancer survivors.

This evidence includes multiple trials showing no effects on breast proliferation or mammographic density and considerable epidemiologic data showing either no effect or a modest protective role of soy/isoflavone intake on breast cancer risk.

Based on this evidence it seems unlikely that isoflavone consumption at dietary levels (i.e. <100 mg/day) elicits adverse breast cancer-promoting effects in healthy women or breast cancer survivors not undergoing active treatment.

Messina MJ and Wood CE; Nutrition Journal 2008.  For the full reference, CLICK HERE 

SOY AND ITS AFFECTS ON BREAST CANCER
Several earlier studies suggested that whole soy foods appeared to have no negative or positive effect on breast cancer. For example the following two studies found soy foods had no negative impact on breast cancer survival.

Boyapati SM, et al. Soyfood intake and breast cancer survival: a followup of the Shanghai Breast Cancer Study. Breast Cancer Res Treat. 2005;92(1):11-17.

Nishio K, et al. Consumption of soy foods and the risk of breast cancer: findings from the Japan Collaborative Cohort (JACC) Study. Cancer Causes Control. 2007;18(8):801-808.

This, and other evidence, prompted Messina and colleagues in their 2008 review quoted above to state:

Available data on breast cancer recurrence and mortality provide some assurance for breast cancer patients that soyfoods/isoflavone supplements, when taken at dietary levels, do not contribute to recurrence rates although more data are clearly needed to better address this issue.

Currently there are no data to support the idea that soyfoods or isoflavone supplements improve the prognosis of breast cancer patients.

However, in 2009, following more analysis of the Shanghai study, strong new evidence was published showing significant benefits of consuming soy for women with breast cancer in terms of better survival and less cancer recurrence, making Messina’s claim seem outdated.

Women consuming soy in the highest quartile had a 29% lower death rate over the 4 year follow up, and 32% reduced risk of recurrence. The protective effect was present regardless of oestrogen receptor status of the cancer, or whether tamoxifen was used or not.

This is the most compelling evidence to date of a benefit for soy consumption by women with breast cancer (as opposed to no harm). It is important because it shows a benefit for increased soy consumption irrespective of oestrogen receptor status or tamoxifen use.
Shu XO et al. Soy food intake and breast cancer survival; JAMA. 2009 Dec 9; 302(22):2437-43.
For the full reference, CLICK HERE

BUT BEWARE:  NATURAL SOY, PROCESSED SOY – DIFFERENT OUTCOMES
However, it may be that the non-traditional soy foods do create problems. Significantly, soy protein isolates do not contain many of the bioactive components present in whole soy. As we clarified last week, refined products include soy flour and its processed derivatives.

Research has demonstrated that soy protein isolates (85–90% soy protein) do stimulate the growth of estrogen-dependent tumors. Another study evaluated the relative effects of different degrees of soy processing on the growth of pre-existing tumors and demonstrated that consumption of isoflavones in increasingly purer or more highly enriched forms may have a proportionally worse effect on estrogen-dependent tumor growth.

Allred CD,et al. Soy processing influences growth of estrogen-dependent breast cancer tumors. Carcinogenesis 2004;25:1649-1657.

Some research has shown that soy processing increases breast cancer growth in mice. This may be related to isoflavone metabolism and bioavailability, but more research is needed.
Allred CD, et al. Soy processing influences growth of estrogen-dependent breast cancer tumors. Carcinogenesis 2004;25:1649-1657.

SOY AND TAMOXIFEN
There has also been some concern expressed that soy products may actually interfere with the action of tamoxifen itself. However, recent studies examining the interaction between soy and tamoxifen have yielded neutral or beneficial findings.

In one study, soy intake had no effect on levels of tamoxifen or its metabolites.
Wu AH, et al. Tamoxifen, soy, and lifestyle factors in Asian American women with breast cancer. J Clin Oncol. 2007;25(21):3024-3030.

In another, the combination of tamoxifen and genistein inhibited the growth of human breast cancer cells in a synergistic manner in vitro.
Mai Z, et al. Genistein sensitizes inhibitory effect of tamoxifen on the growth of estrogen receptor- positive and HER2-overexpressing human breast cancer cells. Mol Carcinog. 2007;46(7):534-542.

SOY AND YOUNG GIRLS
Of great interest is research that demonstrates eating soy foods during childhood and adolescence in women, and before puberty onset in animals, appears to significantly reduce the risk of breast cancer later in life.

SYNERGISTIC EFFECTS OF SOY
Research evidence indicates a possible synergistic relationship between soy and green tea consumption.

SOY AND THE AUTHORITIES
The American Cancer Society in 2006 concluded that breast cancer patients can safely consume up to three servings of traditional soyfoods per day, although the group advised against the use of more concentrated sources of isoflavones such as powders and supplements.

The United States Health and Human Services Agency for Healthcare Research and Quality (AHRQ) conducted a review of the available studies and found little evidence of substantial health improvements and no adverse effects, but also noted that there was no long-term safety data on estrogenic effects from soy consumption.

The AHRQ report notes that future studies of the health effects of soy need to better address the complex relationship between health and food components, including how variations in the diets, lifestyles, and health of participants might affect the results. Also, studies that substitute practical amounts of soy products into people's diets would better address the question of whether people should make the effort to include more soy in their diet.

The Cancer Council of New South Wales released a statement saying scientific research suggests that overall the moderate consumption of soy products does not appear to present a risk to women with breast cancer, and there is equivocal evidence that consuming large amounts of soy products may have a protective effect against developing breast and prostate cancer. However, the Council does not recommend taking soy dietary supplements as there is no evidence they are either effective or safe at preventing or treating cancers.

WHAT RUTH AND I DO
We regularly eat organic tofu and soy yoghurt (which Ruth makes from Bonsoy). Ruth drinks small amounts of soymilk (mostly Bonsoy in teas), but I do not – I do not like it and have teas and dandelion coffee black). We eat some tempeh but only have silken tofu if ordered by mistake when eating out! We avoid processed soy products and read labels to avoid the myriad of foods with these products added to them.

MY OWN CONCLUSIONS and RECOMMENDATIONS
In answer to the key question, I conclude the phyto-oestrogens in soy act like tamoxifen not like oestrogen. Based on the evidence available, soy eaten in its traditional forms acts as an oestrogen antagonist, making it helpful in preventing and overcoming both breast cancer and prostate cancer. I also conclude:

1. Traditional soy foods are almost certainly safe and warrant being a part of a healthy diet for healthy people. I recommend them. I particularly recommend regular soy consumption for young and adolescent girls; but then lifetime consumption seems ideal.

2. Processed or refined or concentrated soy products run the real risk of being problematic for everyone. I do not recommend them.

3. For women with breast cancer, the best evidence currently available suggests traditional soy foods, eaten in traditional amounts are likely to be safe and may well be helpful in reducing recurrences and extending survival. I recommend them.

RELATED BLOGS
Is soy safe? - Part 1

Coconut oil – are you nuts?

Food for life – what to eat when

RESOURCES
You Can Conquer Cancer – the revised edition has many other explanations like this one on soy. What type of protein and how much? Which are the best fats to eat and to avoid, and so on. This book is about prevention and long-term good health, as well as cancer recovery.

NOTICEBOARD
1. NEXT WORKSHOP in the Melbourne region: Inner Peace, Outer Health

Mt Macedon on Saturday August 24th, 10am (arrive 9.30) to 4.30pm

Duneira is an exquisite heritage hill station property on the slopes of Mt Macedon. The garden is like a meditative space, so beautiful and filled with majestic trees. I love being there!

Then the house itself is grand enough to host good sized but still quite intimate events. There is a tradition now at Duneira of hosting community events that range from music to personal development and Ruth and I have become regulars.

So, fancy a nice drive to a beautiful place for a meaningful event? If so, CLICK HERE





2. MEDITATION in the DESERT

The experience of a lifetime. Seven day meditation retreat with Ian and Ruth in the extraordinary, natural meditation space of the Central Australian Desert, followed by a few days being in the company of senior local indigenous leaders.

For full details, CLICK HERE










3. IMAGES, WORDS AND SILENCE


Five day retreat/training for everyone interested in Insight, Healing and Wellbeing.

At the Foundation's centre in the Yarra Valley with Drs Ruth and Ian Gawler and Dr Nimrod Sheinman, world authority on the use of creative imagery for healing and personal development.

For full details, CLICK HERE

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