Soy Protein Isolate and Cancer

July 13, 2005

Hi folks:

The following suggests that SPI confers protection against three

major forms of cancer in rats - breast, colon and prostate:

" Soy protein isolate and protection against cancer.

Badger TM, Ronis MJ, Simmen RC, Simmen FA.

Arkansas Children's Nutrition Center and Department of

Physiology/Biophysics, University of Arkansas for Medical Sciences,

Little Rock, AR 72202, USA. badgerthomasm@...

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. "

PMID: 15798082

Rodney.

Recommended Posts