Dr.Mike Fitzpatrick environmental scientist and phytoestrogen researcher: Downsides of Soy

[Guest guest]

Do Soy Foods Negatively Affect Your Thyroid? / Downsides of Soy

Dr.Mike Fitzpatrick environmental

scientist and phytoestrogen researcher: Downsides of Soy

 

 

 

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http://www.thyroid-info.com/articles/soydangers.htm

 

 

 

Do Soy Foods Negatively Affect Your Thyroid? / Downsides of Soy

 

 

by Mary Shomon

 

It seems that there's isn't a newspaper, magazine or news program that

hasn't recently featured a story on the amazing health benefits of soy

food products and soy/isoflavone supplements. Soy is promoted as a

healthy alternative to estrogen replacement for some women, as a

possibly way to reduce the risk of breast cancer, as a way to minimize

menopause symptoms, and as a healthier, low-fat protein alternative for

meats and poultry. But what all the positive stories fail to mention is

that there is a very real -- but very overlooked -- downside to the

heavy or long-term use of soy products.

Soy products increase the risk of

thyroid disease. And this danger is particularly great for infants on

soy formula.

This is not information that the

powerful and profitable U.S.

soy industry wants you to know. The sale of soy products is big

business, and the increasing demand for soy protein products, soy

powders and soy isoflavone supplements is making that an even more

profitable business than ever before.

In researching my

upcoming book, which covers the issue of soy products and the

thyroid in great depth, I talked to Dr. Mike Fitzpatrick, an

environmental scientist and phytoestrogen researcher who has conducted

in-depth studies on soy, particularly the use of soy formulas. Dr.

Fitzpatrick makes it clear that soy products can have a detrminental

affect on both adults and infants. In particular, he firmly believe

that soy formula manufacturers should remove the isoflavones -- that

part of the soy products that act as anti-thyroid agents -- from their

products.

Researchers have identified that the

isoflavones act as potent anti-thyroid agents, and are capable of

suppressing thyroid function, and causing or worsening hypothyroidism.

Soy is a phytoestrogen, and therefore acts in the body much like a

hormone, so it's no surprise that it interacts with the delicate

balance of the thyroid's hormonal systems. High consumption of soy

products are also proven to cause goiter, (Anti-thyroid

isoflavones from soybean: isolation, characterization, and mechanisms

of action, Divi RL; Chang HC; Doerge DR, National Center for

Toxicological Research, Jefferson, AR 72079, USA, Biochem Pharmacol,

1997 Nov, 54:10, 1087-96)

 

 

 

 

 

Note: The best source of information

on soy and its negative impact on health can be found at the Soy Online Service, and

in particular, its page on phytoestrogenic effects of soy, and impact on the

thyroid.

 

 

 

 

 

Isoflavones belong to the flavonoid or bioflavonoid family of

chemicals, and are considered endocrine

disruptors -- plants or other products that act as hormones,

disrupting the endocrine system, and in some cases, this disruption

involves acting as an anti-thyroid agent. (The grain millet, for

example, contains high levels of flavonoids, and is commonly known as

problematic for thyroid function). Flavonoids inhibit thyroid

peroxidase (TPO), which disturbs proper thyroid function.

The March 1999 issue of Natural

Health magazine has a feature on soy that quotes Daniel R. Doerge,

Ph.D., a researcher at the Food and Drug Aministration's National

Center for Toxicological Research. Dr. Doerge has researched soy's

anti-thyroid properties, and has said "...I see substantial risks from

taking soy supplements or eating huge amounts of soyfoods for their

putative disease preventive value. There is definitely potential for

interaction with the thyroid."

One UK study of premenopausal women gave

60 grams of soy protein per day for one month. This was found to

disrupt the menstrual cycle, with the effects of the isoflavones

continuing for a full three months after stopping the soy in the diet.

Isoflavones are also known to modify fertility and change sex hormone

status. Isoflavones have been shown to have serious health effects --

including infertility, thyroid disease or liver disease -- on a number

of mammals.

Dr. Fitzpatrick believes that people

with hypothyroidism should avoid soy products, because, "any inhibition

of TPO will clearly work against anyone trying to correct an

hypothyroid state." In addition, he believes that the current promotion

of soy as a health food will result in an increase in thyroid

disorders.

The Dangers of Soy

Formulas

 

Since the late 1950's, it has been known

that soy formulas contain anti-thyroid agents. Infants on soy formula

are particularly vulnerable to developing autoimmune thyroid disease

when exposed to high exposure of isoflavones over time. (

Breast and soy-formula feedings in early infancy and the prevalence

of autoimmune thyroid disease in children. Fort P; Moses N;

Fasano M; Goldberg T; Lifshitz F Department of Pediatrics, North Shore

University Hospital-Cornell University Medical College, Manhasset, New

York 11030. J Am Coll Nutr, 1990 Apr, 9:2, 164-7) This study found that

the frequency of feedings with soy-based milk formulas in early life

was noticeably higher in children with autoimmune thyroid disease, and

thyroid problems were almost triple in those soy formula-fed children

compared to their siblings and healthy unrelated children. Dr.

Fitzpatrick even believes that long-term feeding with soy formulas

inhibits TPO to such an extent that long-term elevated TSH levels can

also raise the risk of thyroid cancer.

Not much is being done in the U.S. to

make parents aware of the thyroid-related dangers of soy formulas, or

to alert the public that heavy soy consumption may be a danger to

thyroid function. Other countries, however, are far ahead of the U.S.

In July of 1996, the British Department of Health issued a warning that

the phytoestrogens found in soy-based infant formulas could adversely

affect infant health. The warning was clear, indicating that soy

formula should only be given to babies on the advice of a health

professional. They advised that babies who cannot be breastfed or who

have allergies to other formulas be given alternatives to soy-based

formulas.

Why more information is not available

about these concerns is probably a function of the tremendous strength

of the large agricultural companies that dominate America's soy market.

One thing is clear, however. At the same time that health experts, and

nearly every radio and television health program in the nation touts

soy as the miracle health food of the new millenium, the United States

pediatric and medical community needs to get more on top of this issue,

and begin to counsel their patients regarding the serious impact use of

soy products can have on thyroid function.

How Much Soy is Safe?

 

 

According to the Soy Online Service, for

infants, any soy is too much. For adults, just 30 mg of soy isoflavones

per day is the amount found to have a negative impact on thyroid

function. This amount of soy isoflavones is found in just 5-8 ounces of

soy milk, or 1.5 ounces of miso. For more information on how much soy

is too much, see the Soy Online

Service guidance page.

 

The USDA has launched a website that is promoting the health benefits

of use of soy and soy foods. The USDA

site lists the isoflavone content of a total of 128 foods,

including foods such as vegetarian hot dogs soybeans, chickpeas and

tofu. This can help you in deciding how much soy to include in your

diet.

 

More information

For more information on soy products,

see:

 

 

Soy Online Service

Soy's Negative

Impact on The Thyroid: Thyroid Disease Net Links, a comprehensive

listing I've developed

All

About Soy, About.com's Nutrition Guide Rick Hall's excellent list

of soy-related resources

Food

and Drug Administration Approves New Health Claim for Foods Containing

Soy, October 1999 article discussing this FDA approval, from

About.com Nutrition Guide, Rick Hall.

Concerns Regarding

Soybeans, from the Rheumatic Diseases website

Are Soy Products Dangerous?,

from the Gerson Healing Newsletter, Vol. 11, No. 5, Sep./Oct. 1997

About.com's

Vegetarian Guide covers "The Joy of Soy"

Guide to

Soy Isoflavones

Soy

to the World: A Guide to Incorporating Soy into Your Diet