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DURHAM, N.C. -- A diet low in carbohydrates may help stunt
the growth of prostate tumors, according to a new study led by
Duke Prostate Center researchers. The study, in mice, suggests
that a reduction in insulin production possibly caused by fewer
carbohydrates may stall tumor growth.

"This study showed that cutting carbohydrates may slow tumor
growth, at least in mice," said Stephen Freedland, M.D., a
urologist at Duke University Medical Center and lead researcher
on the study. "If this is ultimately confirmed in human
clinical trials, it has huge implications for prostate cancer
therapy through something that all of us can control, our
diets."

Freedland conducted most of the research for this study
while doing a fellowship in urology at Johns Hopkins' Brady
Urological Institute under the tutelage of William Isaacs,
Ph.D., a molecular geneticist there.

The researchers published their results on November 13, 2007
in the online edition of the journal Prostate. The study was
funded by the Department of Veterans Affairs, the Department of
Surgery and the Division of Urology at Duke University Medical
Center, the Prostate Cancer Foundation, and the Department of
Defense Prostate Cancer Research Program.

The researchers hypothesized that since serum insulin and a
related substance known as insulin-like growth factor (IGF) had
been linked with the growth of prostate tumors in earlier
research in mice, a reduction in the body's levels of these
substances might slow tumor growth, Freedland said.

The researchers compared tumor growth in 75 mice that were
eating either a low-carbohydrate diet, a low-fat but
high-carbohydrate diet, or a Western diet, high in fat and
carbohydrates.

The mice that ate a low-carbohydrate diet had the longest
survival and smallest tumor size, Freedland said.

"Low-fat mice had shorter survival and larger tumors while
mice on the Western diet had the worst survival and biggest
tumors," he said. "In addition, though both the low-carb and
low-fat mice had lower levels of insulin, only the low-carb
mice had lower levels of the form of IGF capable of stimulating
tumor growth."

The low-carbohydrate diet definitely had the most
significant effect on tumor growth and survival, he said.

The next step will be to test the findings of this study in
humans, and further examine the potential positive effects that
a low-carbohydrate diet may have on tumor growth, Freedland
said.

"We are planning to start clinical trials sometime next
year," he said. "The results of this study are very promising,
but of course much more work needs to be done."

Other study authors include John Mavropoulos, Timothy
Fields, Salvatore Pizzo and Bercedis Peterson of Duke; Amy Wang
and Medha Darshan of Johns Hopkins University; William Aronson,
Pinchas Cohen and David Hwang of UCLA; and Wendy
Demark-Wahnefried of MD Anderson Cancer Center.