No Research?
A common anti-biotech refrain is
that, one, scant and irrelevant research has been done on the safety
of transgenic soybean derived food; two, that transgenic soybeans
are inherently inferior in nutrition, including isoflavones.
Does conclusive bear this out? Just the opposite ...
Subjects
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1. Substantial equivalence in classic and transgenic soybean,
including the RR sprayed RR tolerant ones,
see Taylor et al. 1999
2. Isoflavone level varies widely in soybean
3. Isoflavone level varies also in processed soybean derived food.
KEY SCIENTIFIC LITERATURE
1. Research data demonstrates that Roundup Ready soybeans and
conventional soybeans are substantially equivalent in composition,
safety and nutritional value.
RESOURCES
Composition studies show that isoflavone (also called phytoestrogen)
levels are equivalent in Roundup Ready and conventional soybeans. Both
Roundup Ready and conventional soybeans show a very wide range of
phytoestrogen levels (5-6 fold) when grown under different environmental
conditions.
Padgette, S.R. et al. (1996). The composition of glyphosate-tolerant
soybean seeds is equivalent to that of conventional soybeans. Journal of
Nutrition 126:702-716
Data from 1992 and 1993 unsprayed Roundup Ready soybean and parental line
(A5403) - 9 locations, isoflavone analysis of whole grain and toasted meal
showed wide variability (5-6 fold) but no significant difference between
Roundup Ready soy and the parental line.
The levels of isoflavones in Roundup Ready soybeans and conventional
soybeans are the same, even when Roundup is applied.
Taylor N.B., R.L. Fuchs, J. McDonald, A.R. Shariff and S.R. Padgette.
(1999). Compositional analysis of glyphosate-tolerant soybeans treated with
glyphosate. Submitted Journal of Agricultural and Food Chemistry
Data from the 1993 sprayed glyphosate-tolerant (Roundup Ready) soybean and
unsprayed parental control (A5403) - 4 locations, isoflavone (6 components)
analysis of whole grain. Study confirms that the application of glyphosate
on Roundup Ready soybeans does not effect the levels of isoflavones or
other nutritional factors. Site to site variability in isoflavone levels
was high with data varying 4-7 fold, with no significant differences
between Roundup Ready soybean and the parental line.
2. Isoflavone levels vary widely between soybean varieties and in
soybeans grown under different environmental conditions.
RESOURCES
A single soybean variety contained isoflavone (phytoestrogen) levels that
varied 3 fold from year to year. A 2-5 fold variation was observed between
11 US and Japanese varieties.
Wang, H. and P.A. Murphy. (1994). Isoflavone composition of American and
Japanese soybeans in Iowa: Effects of variety, crop year, and location. J.
Agric. Food Chem. 42:1674-1677.
Isoflavone (12 components) levels measured in whole seed. Using a single
variety over three years, total isoflavones were significantly different
(varied 3-fold) from year to year. Analysis on 8 conventional US varieties
and 3 Japanese varieties found wide variation (2-5 fold) in isoflavone
levels that were significantly different between varieties.
Brazilian conventional soybean varieties showed wide variability between
varieties and differed significantly between years. The variability
observed was 3-8 fold.
Carrao-Panizzi, M. and Kitamura, K. (1995). Isoflavone content in
Brazilian soybean cultivars. Breeding Science 45:295-300.
22 conventional Brazilian soybean cultivars were analyzed for isoflavone
content (2 components) over 2 years. Isoflavone content was significantly
different among cultivars and between years and varied widely (3-8 fold).
Total isoflavone levels varied 2-3 fold between 4 soybean varieties.
This variability was attributed to climatic and environmental factors.
Eldridge, A. C. and Kwolek, W. F. (1983). Soybean isoflavones: Effect of
environment and variety on composition. Journal of Agriculture Food Chem.
31:394-396.
Total isoflavone (6 components) in whole beans was analyzed across 4
varieties and across two years. Values varied widely from variety to
variety (2-3 fold) and there were also significant differences (3-5 fold)
when the same variety is grown in different locations. "Significant
variation among years suggests that unknown climatic and environmental
factors contribute to variation in isoflavones".
Additional supporting literature.
Fukutake, M., Takahashi, M., Ishida, K., Kawamura, H., Sugimura, T. and
Wakabayashi, K. (1996). Quantification of genistein and genistin in
soybeans and soybean products. Food and Chemical Toxicology 34:457-461.
Choi, J-S., C., Kwon,T-W. and Kim, J-S. (1996). Isoflavone contents in
some varieties of soybean. Foods and Biotechnology 5:167-169.
Naim, M., Gestetner, B., Zilkah, S., Birk, Y. and Bondi, A. (1976).
Soybean isoflavones, characterization, determination, and antifungal
activity. Agric. Food Chem. 22:806-810.
3. Isoflavone variability is also observed in processed soy food products.
A database is available that reports the isoflavone levels in food and
food products. Isoflavones vary significantly in foods and food products.
USDA-Iowa State University Database on the Isoflavone Content of
Foods - 1999
Web address: http://www.nal.usda.gov/fnic/foodcomp/Data/isoflav/isoflav.html
A comprehensive database and analysis of isoflavone levels in the major
food sources (legumes species and processed products) of phytoestrogens in
human diet. Includes data reported from references with means, ranges, and
statistics. Isoflavone variation of US commodity soybean showed ranges of
3.5 fold for genistein, 3.8 fold for diadzein and 3.3 fold for total
isoflavone.
Murphy, P.A., Barua, K. and Song, T. Soy isoflavones in foods: Database
development. In: American Chemical Society Symposium Series: Functional
Foods: Overview and Diseases Prevention, ed. T.Shibamoto. In press.
Describes justification for, data compilation, variability, utility,
interpretation and quality control of the database.
Isoflavone levels vary by food product, sometimes as high as in whole bean
and sometimes below limit of detection due to losses during processing.
Fukutake, M., Takahashi, M., Ishida, K., Kawamura, H., Sugimura, T. and
Wakabayashi, K. (1996). Quantification of genistein and genistin in
soybeans and soybean products. Food and Chemical Toxicology 34:457-461.
Describes levels of the phytoestrogens genistein and genistin in soybean,
soy nuts, soy powder, soy mil, and tofu. Levels of genistein and genistin
ranged from 4.6-18.2 and 200.6-968.1 ug/g food weight in soybean, soy nuts,
soy powder and from 1.9-13.9, 94.8-137.7 ug/g food weight in soy milk and
tofu.
Studies show that significant isoflavone losses occur during processing of
soybeans.
Wang, C., Ma, Q., Pagadala, S., Sherrad, MS. and Krishnan, PG. (1998).
Changes of isoflavones during processing of soy protein isolates. Am. Oil
Chemists Society 75:337-341.
Mass balance changes during processing. Describes losses of isoflavone
during different steps of processing of soybeans into soy protein isolates.
Study revealed that only 26% of total isoflavone remained in final
processing step.
Wang, H-J. and Murphy, P. A. (1996). Mass balance study of isoflavones
during soybean processing. Agric. Food Chem. 44:2377-2383.
Mass balance changes during processing. Describes losses of isoflavone
during different steps of processing of soybeans tempe, soy milk, tofu and
protein isolate.
Wang, H-J. and Murphy, P. A. (1994). Isoflavone content in commercial
soybean foods. Agric. Food Chem. 42:1666-1673.
Concentration of isoflavone was analyzed in 29 commercial soy foods. High
protein soy ingredients had isoflavone levels similar to that to
unprocessed beans.
EXPERTS
Dr. Clare Hasler
Executive Director
Functional Foods for Health Program
University of Illinois at Urbana-Champaign
103 Agricultural Bioprocess Lab. (M/C 640)
1302 West Pennsylvania Ave.
Urbana, IL 61801
217-333-6363
217-333-7386 fax
Dr. Clare Hasler is the Executive Director of Functional Foods for Health
(FFH), a joint program of the University of Illinois at Chicago and the
University of Illinois at Urbana-Champaign, dedicated to the improvement of
human health through multi-disciplinary research, education and
communication focused on the identification of safe and efficacious foods
and other physiologically active natural products which may reduce chronic
disease risk or promote optimal health. Her research has dealt with the
health benefits obtained from consumption of soy protein products. Dr.
Hasler was a recipient of the 1997 Illinois Soybean Association's Friend of
Agriculture Award.
Dr. Patricia Murphy*
Professor, Food Science and Human Nutrition
Iowa State University, 2312 Food Science Building, Ames, Iowa 50011-1061
Phone 515-294-1970
Fax 515-294-8181
Dr. Patricia Murphy has been studying and testing isoflavones for nearly 20
years and has been in the forefront of understanding the role isoflavones
have in human health. She is the developer of the U.S. Department of
Agriculture and Iowa State University Isoflavone Database, an authoritative
database of the isoflavone content of human foods which will help
scientists pinpoint which estrogen-like compounds -- isoflavones -- in soy
foods may be responsible for a lower risk of cancer, especially breast
cancer. A recipient of the Iowa State Board of Regents Faculty Excellence
Award.
Dr. Stephen Barnes
Professor, Department of Biochemistry and Pharmacology
Department of Pharmacology, University of Alabama at Birmingham, Volker
Hall, Rm G010 UAB Station, Birmingham, Alabama 35294
Phone 205-934-7117
Fax 205-934-8240
Dr. Barnes is a recognized expert in the field of isoflavone analyticals
and the role these compounds play in preventing cancer. Trained in London,
England, he joined the Mayo Clinic in Rochester, Minnesota in 1975. He has
been at the University of Alabama-Birmingham since 1977 and is a Professor
in the Departments of Pharmacology & Toxicology and Biochemistry &
Molecular Genetics. He is also the Director of the Comprehensive Cancer
Center Mass Spectrometry Shared Facility. He serves as an advisor to the
UK's MAFF on the issue of phytoestrogens in foods.
Dr. Pam White
Department of Food Science
Human Nutrition
Iowa State University
Ames, Iowa
Phone 515-294-9688
Fax 515-294-8181
Dr. Pam White is a leading researcher in the area of the functional
properties of foods, including soybean, corn and oats. Dr. White is former
chair of the Department of Food Science at Iowa State University.