SOS Guidance
What
we think you should be doing about phytoestrogens and
soy.
How much soy is safe to eat?
For infants, we believe any soy is too much soy.
Adults consuming soy should also exercise caution. As Dr Daniel
Sheehan, Director of Reproductive Toxicology at the USA Department of
Health and Human Servises' Research Center says "No dose is without
risk; risk is a function of dose" in this letter to his head office
opposing "health" claims for soy protein. Follow the following link to
Dr Sheehans letter.
http://abcnews.go.com/onair/2020/2020_000609_soyfdaletter_feature.html
The observations from the Ishizuki Thyroid Clinic
study indicate significant, goitrogenic effects in subjects fed 30 g
soybeans per day. Based on the concentrations of isoflavones found in
Japanese soybeans, 30 g of soybeans could contribute up to 23 mg total
genistein and 10 mg of total daidzein. For a 70 kg adult this would
equate to an intake of 0.33 mg/kg-body weight of genistein and 0.14
mg/kg-body weight of daidzein per day.
This amount of isoflavone consumption is
approximately three times higher than the amount typically consumed in
Japan, which is 0.08 to 0.13 mg/kg-body weight of total genistein per
day for a 70 kg adult.
For infants fed soy-formulas, the exposure to
isoflavones is greater than in any other population group. Infants less
than 6 months of age who are solely fed soy formula have an intake of
up to 5.4 mg/kg-body weight of genistein and 2.3 mg/kg-body weight
basis of daidzein per day. Hence, soy formula fed infants are exposed
to approximately 16 times greater levels of isoflavones than the
subjects in the Ishizuki study.
The concentrations of isoflavones found in soy
products can vary but studies from New Zealand indicate that a diet of
500g of soy milk plus 200g tofu per day would result in the consumption
of up to 135 mg total genistein and 80 mg total daidzein. For a 70 kg
adult this equates to an intake of 1.9 mg/kg-body weight of genistein
and 1.1 mg/kg-body weight of daidzein per day. This degree of exposure
to isoflavones is more than five times that of subjects in the
investigation by Ishizuki.
Users of isoflavone supplements may consume up to
40 mg of genistein per day. For a 70 kg adult this is equivalent to
0.57 mg/kg-body weight basis of genistein per day which is about 1.7
times more than that found to have goitrogenic effects.
Therefore, soy formula fed infants, high soy
consumers and users of isoflavone supplements might exhibit classic
hypothyroid symptoms without recognising a dietary connection.
Unfortunately there is little data as what constitutes an appropriate
level of soy intake, although it appears that some western consumers
may now be eating far greater amounts of soy than that taken as part of
a traditional Asian diet.
Soy users should be aware of the potency of just
30 mg soy isoflavones per day. Thyroid disorders (see above for
discussion on the active dose in the Ishizuki Thyroid Clinic study) and
other biological effects have been observed at dose around this
level.
As an approximate guide 30 mg of soy isoflavones
can be found in:
Soybeans and soyflours: 9
- 20g (0.3 - 0.7oz).
Soy mince: 12g (0.4oz).
Tofu: 50 - 110g (1.8 -
3.9oz).
Soy milks: 150 - 240g (5.3
- 8.5oz).
Miso: 35 - 45g (1.2 -
1.6oz).
Soybean sprouts: 80g
(2.8oz).
What products contain soy?
As well as obvious soyfoods like tofu, soy milk
and miso, and other soy products such as isolated soy protein (ISP) and
soy protein concentrate (SPC), very many processed foods contain soy,
some examples are:
Biscuits |
Breads |
Vegetarian burgers |
Cakes |
Crackers |
Bakery products |
Pastries |
Meat substitutes |
Pancakes |
Chicken nuggets |
Legume meal |
Fish fingers |
Pies |
Meat extenders |
Hydrolysed vegetable protein (HVP) |
Yoghurt |
Breakfast cereals |
Sausages |
Soups |
Baby foods |
Doughnuts |
Vegetarian meats |
Sandwich spreads |
Baby rusks |
Pet Foods |
Animal feeds |
Textured vegetable protein (TVP) |
Why isn't this information readily available?
People deserve the right to know about what they are eating and what
they are feeding their children. So why are government agencies so
reluctant to share information with the public?
New Zealand environmental scientist and phytoestrogen researcher Dr
Mike Fitzpatrick met with California DHS staff in June 1998 to express
his concerns about soy, and particularly soy formulas. He received a
written response from DHS toxicologist Dr Susan Loscutoff. Loscutoff
stated:
"I agree that high levels of dietary exposures to isoflavones in
infants fed soy-based formulas is cause for concern."
"I do not agree that parents have a right to know that soy-based
formulas contain isoflavones and the kinds of toxicities isoflavones
might demonstrate in infants, since parents would not know how to
interpret the information."
This kind of response it quite typical of agencies fearing a severe
backlash from the soy lobby should they alert the public to the
potential health concerns of soy isoflavones.
What else can I do?
Write to your National or State Health Department representatives
demanding information on the risks associated with the consumption of
soy isoflavones, especially by infants, and the safety of isoflavone
supplements/OTC-drugs.
Write to potentially sympathetic politicians (e.g. in the US Senator
Barbara Boxer or Senator Fred Lautenberg), and express your concern
about the presence of isoflavones in soy formulas. Ask for
clarification regarding the safety of soy formulas and soy isoflavone
supplements/OTC drugs.
Share this information with your health professionals and
friends.
Be prepared for a 'no evidence of harm' response from government
agencies. The facts, however, tell a different story.
Soy Free Manufactured Foods
The Manufactured Food Database (MFD) has been compiled by Nutrition
Services, Auckland Hospital from information voluntarily supplied by
New Zealand Food Manufacturers. This database provides information on
which products have been declared Soy free.
For further education on advice on soy alternatives, please visit
the following links.
HiddenSoy.com:
http://www.hiddensoy.com/. This is Diane Gregg's (Author of "The
Hidden Dangers of Soy") website, where you can find information
on
- What ingredients to look for on the labels so you know exactly
which foods contain soy and which do not.
- What alternative ingredients to use including recipes that are
soy free.
- Why the soybean industry wants you to believe it's the "miracle"
food.
- You will read testimonials from others and how soy affected
them.
SoyFreeSolutions.com:
http://www.soyfreesolutions.com/. The website of Kaayla T Daniel,
PhD. SOY FREE SOLUTIONS is for you if you are allergic to soy,
sensitive to soy, or just don't want soy in your life.
SOY FREE SOLUTIONS is for you if you desire high-quality vitamins
and other nutritional supplements, shakes, energy bars, and other
products that are completely soy free and not readily available in
stores.
Soy Allergies
It is not widely known that soy is one of the most allergenic foods
in modern diets. It is reported in several research reports to contain
at least 30 allergenic proteins. Find out more about soy allergies on
our Soy Allergies page.
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