Limiting the intake of carbohydrates - regardless of weight loss - appears to slow the growth of prostate tumors, according to a new study undertaken by the Duke University Prostate Center.
"Previous work here and elsewhere has shown that a diet light in carbohydrates could slow tumor growth, but the animals in those studies also lost weight, and because we know that weight loss can restrict the amount of energy feeding tumors, we weren't able to tell just how big an impact the pure carbohydrate restriction was having, until now," said Duke urologist Stephen Freedland.
The researchers hypothesize that insulin and insulin-like growth factor contribute to the growth and proliferation of prostate cancer, and that a diet devoid of carbohydrates lowers serum insulin levels in the bodies of the mice, thereby slowing tumor growth.
The animals in the study were fed one of three diets: a very high fat/no carbohydrate diet; a low-fat/high carbohydrate diet; and a high fat/moderate-carbohydrate diet, which is most similar to the "Western" diet most Americans eat. They were then injected with prostate tumors at the same time.
The researchers found that the mice that were fed a no-carbohydrate diet experienced a 40 to 50 percent prolonged survival over the other mice. Mice on the no-carbohydrate diet consumed more calories in order to keep body weights consistent with mice on the other study arms. "We found that carbohydrate restriction without energy restriction - or weight loss - does indeed result in tumor growth delay," Freedland said.
The researchers plan to begin recruiting patients at two sites - Duke and the University of California - Los Angeles - for a clinical trial to determine if restricting carbohydrate intake in patients with prostate cancer can similarly slow tumor growth. The trial should begin within a few weeks.
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Source: Duke University Medical Center