Fwd: The scoop on oxalates in soy

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Trying_Low_Oxalates , Susan Owens <lwo wrote:

Web address:

http://www.sciencedaily.com/releases/2001/08/010829083130.htm Source:

American Chemical Society August 29, 2001 More on: Kidney

Disease, Urology, Cholesterol, Diseases and Conditions, Food, Obesity

 

Too Much Soy Could Lead To Kidney Stones

 

Science Daily ­ New research indicates that soybeans and soy-based

foods, a staple in the diets of many health-conscious consumers, may

promote kidney stones in those prone to the painful condition. The

finding will be published in the September issue of the Journal of

Agricultural and Food Chemistry, a peer-reviewed journal of the

American Chemical Society, the world's largest scientific society.

 

The researchers measured nearly a dozen varieties of soybeans for

oxalate, a compound that can bind with calcium in the kidney to form

kidney stones. They also tested 13 types of soy-based foods, finding

enough oxalate in each to potentially cause problems for people with a

history of kidney stones, according to Linda Massey, Ph.D., at

Washington State University in Spokane. The amount of oxalate in the

commercial products easily eclipsed the American Dietetic

Association's 10 milligram-per-serving recommendation for patients

with kidney stones, with some foods reaching up to 50 times higher

than the suggested limit, she noted.

 

" Under these guidelines, no soybean or soy-[based] food tested could

be recommended for consumption by patients with a personal history of

kidney stones, " she said.

 

No one had previously examined soy foods for oxalate, thus the

researchers are the first to identify oxalate in store-bought products

like tofu, soy cheese and soy drinks. Other foods, such as spinach and

rhubarb, also contain significant oxalate levels, but are not as

widely consumed for their presumed health benefits, Massey said.

 

During their testing, the researchers found the highest oxalate levels

in textured soy protein, which contains up to 638 milligrams of

oxalate per 85-gram serving. Soy cheese had the lowest oxalate

content, at 16 milligrams per serving. Spinach, measured during

previous research, has approximately 543 milligrams per one-cup (2 oz.

fresh) serving.

 

Soy, a natural source of protein, fiber and healthy oils, is used to

enhance a myriad of foods, ranging from hamburgers to ice cream. It

can be ground into flour and used in a variety of grain products, or

formed into chunks and ground like meat. Soy is also being studied for

its potential to lower cholesterol, reduce bone loss and prevent

breast cancer. The U.S. Food and Drug Administration recently approved

a new label on foods containing at least 6.25 grams of soy protein per

serving that boasts of a reduced risk of cardiovascular disease.

 

Oxalate, however, cannot be metabolized by the body and is excreted

only through urine, Massey said. The compound has no nutritional

value, but binds to calcium to form a mass (kidney stones) that can

block the urinary system, she said. Further research is needed to find

types of soybeans with less oxalate, or to develop a processing method

to remove the compound before it reaches consumers, she added.

 

No one knows precisely why kidney stones occur in particular

individuals. But Massey said high levels of oxalate in the urine

increase the risk and those with a family history of the ailment are

more likely to suffer from the condition; individuals with a low

probability of kidney stones are unlikely to be affected by oxalate in

soy-based foods.

 

More than one million people were diagnosed with kidney stones in the

United States in 1996, the most recent available data, according to

the National Institutes of Health. Stones can range in size from the

diameter of a grain of rice to the width of a golf ball. An estimated

10 percent of the U.S. population, mostly men, will develop a kidney

stone at some point in their lives, according to the NIH.

 

Note: This story has been adapted from a news release issued by

American Chemical Society.