Nov. 13, 2007 -- Forgoing carbohydrates may slow the growth of prostate cancer, according to preliminary lab tests in mice.
The researchers aren't making dietary recommendations for men. But they say the topic deserves further study.
"This study showed that cutting carbohydrates may slow tumor growth, at least in mice," Duke University urologist Stephen Freedland, MD, says in a news release.
"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," says Freedland, who plans to start such trials next year.
Freedland's team split 75 mice into three groups:
- Low-fat diet: 12% fat, 16% protein, 72% carbohydrate
- Western diet: 40% fat, 16% protein, 44% carbohydrate
- No-carb diet: 84% fat, 16% protein, 0% carbohydrate
After 24 days on the diets, the mice got an injection of human prostate cancer cells.
The mice on the no-carb diet outlived the mice on the Western diet. The no-carb mice also had tumors that were a third smaller after 51 days than the mice on the Western diet.
Tumor growth and survival were similar for the mice on the low-fat and no-carb diets.
"One could argue that the [no-carb] diet provides no advantage and future studies should focus on a low-fat diet," the researchers write in today's online edition of The Prostate.
But they suggest that the no-carb diets may have other advantages, such as greater weight loss and lower levels of a tumor-promoting chemical.
The study's limits include the fact that it only involved mice and its relatively short time span.
Whether the findings apply to people -- and the long-term effects -- remain to be seen.
As Freedland's team notes, the no-carb diet used in their study was very high in fat, and high-fat diets have been linked to greater risk of prostate cancer, heart disease, and other health problems.
The type of fat may make a difference. For instance, Freedland and colleagues got different results in a past study that used corn oil as mice's main source of fat rather than milk fat or lard.
Other researchers have shown that intensive diet and lifestyle changes may slow prostate cancer without requiring anyone to give up carbohydrates.