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Soja als bescherming tegen kanker.*
Uit verschillende onderzoeken blijkt dat soja bescherming kan
bieden tegen borst-, darm en prostaatkanker en bij kanker verdere ontwikkeling
kan tegengaan.
Soy Protein Isolate and
Protection Against Cancer
Thomas M.
Badger, PhD, Martin J. J. Ronis, PhD, Rosalia C. M. Simmen, PhD and Frank A.
Simmen, PhD
Arkansas Children’s Nutrition Center and Departments
of Physiology/Biophysics and Pharmacology/Toxicology, University of Arkansas for
Medical Sciences, Little Rock, AR
Address reprint requests to: Address correspondence to:
Thomas M. Badger, Ph.D., Arkansas Children’s Nutrition Center, 1120 Marshall
Street, Little Rock, Arkansas 72202. E-mail:
badgerthomasm@uams.edu
Objective: Results from
epidemiological and animal studies suggest that consuming
soy-containing diets reduces the incidence of certain cancers. The
purpose of this presentation was to evaluate the potential of soy
protein to prevent occurrence of prostate, breast and colon cancer.
Methods: Meta-analyses of
published epidemiologic studies associating cancer risk with soy
intake were performed. The incidence of chemically-induced mammary or
colon tumors was determined for rats fed AIN-93G diets made with
either casein or soy protein isolate (SPI). Western and Northern blot
and microarray analyses were performed on rat mammary and colon
tissues to study mechanisms underlying the effects of soy.
Results: Meta-analyses
revealed reductions in the mean overall risk estimate for mammary
(0.78, p < 0.001), colon (0.70, p < 0.001) and
prostate (0.66, p < 0.001) cancer for soy consumers. The
incidence of AOM-induced colon tumors and DMBA-induced mammary tumors
was reduced (p < 0.05) in rats fed SPI-containing diets.
Lower incidence of mammary tumors in SPI-fed rats was associated
with: 1) reduced terminal end bud numbers (p < 0.05), 2)
lower expression of the phase I enzyme CYP1B1 (p < 0.05)
and 3) reduced expression of the Ah Receptor and ARNT (p <
0.05).
Conclusions: SPI may protect
against cancer via multiple mechanisms, including: 1) increased
mammary gland differentiation, 2) decreased activation of
procarcinogens to carcinogens and 3) regulation of genes in signal
transduction pathways underlying tumor initiation, promotion and/or
progression. (Mei 2005)