The first diet was a typical Western diet – about 55 percent carbohydrate, 23 percent protein and 22 percent fat. The scientists described the second diet as similar to the South Beach diet, but with more protein. It contained 15 percent carbohydrate, 58 percent protein and 26 percent fat.
The researchers found that among the mice eating a low-carbohydrate, high-protein diet, the tumor cells grew consistently slower, and in some groups, the cancer never developed.
Furthermore, only one of the mice on the Western diet reached a normal lifespan, while 70 percent died from cancer. But only 30 percent of the mice on the low-carbohydrate diet developed cancer, and more than half of them reached or exceeded their normal life span.
Lead researcher Gerald Krystal, Ph.D., a scientist at the British Columbia Cancer Research Centre explained that tumor cells, unlike normal cells, need significantly more glucose to grow and thrive. Restricting carbohydrate intake can significantly limit blood glucose and insulin, a hormone that has been shown in prior studies promote tumor growth in both humans and mice.
Additionally, a low-carbohydrate, high-protein diet has the potential to both boost the ability of the immune system to kill cancer cells and prevent obesity, which leads to chronic inflammation and cancer.
“This shows that something as simple as a change in diet can have an impact on cancer risk,” said Krystal.
Cancer Research editor-in-chief George Prendergast, Ph.D., CEO of the Lankenau Institute for Medical Research, agreed.
“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,” he said.
The study was published in Cancer Research, a journal of the American Association for Cancer Research.