Low carb, high protein diet may reduce cancer risk
MedWire News: A diet low in carbohydrates (CHOs) and high in protein slows tumor growth and reduces tumor incidence, a study in mice has shown.
"Such a diet, therefore, has the potential of being both a novel cancer prophylactic and treatment, warranting further investigation of its applicability in the clinic, especially in combination with existing therapies," Gerald Krystal (British Columbia Cancer Research Centre, Vancouver, Canada) and colleagues report.
Since cancer cells depend, more than normal cells, on glucose to meet their energy needs, Krystal and team compared the effect of a low CHO diet (15% CHO, 58% protein, 26% fat) with that of a Western-style diet (55% CHO, 23% protein, 22% fat) on the growth rate of tumors in mice.
They chose to increase protein, rather than fat, levels in the low-CHO diet because of the reported tumor-promoting effects of high fat and the immune-stimulating effects of high protein.
The researchers found that, compared with mice fed the Western diet, those fed the low-CHO diet exhibited lower blood glucose, insulin, and lactate levels, with little or no effects on weight.
More importantly, both murine and human carcinomas grew more slowly in mice on the low CHO diet compared those on the Western diet. Indeed, tumors were 36%-41% smaller in the low-CHO group versus the Western group.
Furthermore, nearly 50% of mice genetically predisposed to breast cancer (NOP mice), developed tumors by the age of 1 year, whereas no tumors were detected in mice on the low-CHO diet.
Only one of the NOP mice on the Western diet reached a normal life span (approximately 2 years), with 70% dying from cancer. In contrast, more than half of the NOP mice on the low-CHO diet reached or exceeded the normal life span and only 30% developed cancer.
Krystal and colleagues also tested the effect of a mammalian target of rapamycin inhibitor, which inhibits cell growth, and a cyclooxygenase-2 inhibitor, which reduces inflammation, on tumor development. They found that these agents had an additive effect on tumor reduction in the mice fed the low-CHO, high-protein diet.
"Taken together, our findings offer a compelling preclinical illustration of the ability of a low CHO diet in not only restricting weight gain but also cancer development and progression," the authors conclude in the journal Cancer Research.
Cancer Research editor-in-chief George Prendergast (Lankenau Institute for Medical Research, Philadelphia, Pennsylvania, USA) added: "Many cancer patients are interested in making changes in areas that they can control, and this study definitely lends credence to the idea that a change in diet can be beneficial."
MedWire (www.medwire-news.md) is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2011
By Laura Dean