A diet that is low in carbohydrates and high in proteins protects against cancer. Cancer researchers at the University of British Columbia discovered that this kind of diet reduces the chance of cancer developing and inhibits the growth of tumours.
Nutritionists tend to ignore the evidence, but scientists doing fundamental cancer research are convinced: the increasing amount of energy we derive from quickly absorbed carbohydrates [like sugar, glucose and fructose] stimulates cancer.
Cancer cells like to feed on glucose. The more glucose there is in the bloodstream, the more energy they have available to maintain their higher growth rate. What's more, when they convert glucose into energy, cancer cells produce glutathione and lactic acid. They use glutathione to protect themselves against their own suicide mechanisms, and they use lactic acid to make their surroundings more acid. Because healthy cells function less well in a more acid environment, lactic acid gives cancer cells more opportunities for metastasis.
And that's the theory the researchers wanted to test on animals. In their article, which was published in Cancer Research, the researchers describe six experiments they did. In these experiments the mice were given 5058 standard feed, consisting of 55 percent carbohydrates, or feed containing only 8, 10 or 15 percent carbohydrates.
In one experiment the researchers injected the mice with SCCVII cancer cells and then gave them standard feed or feed containing 10 percent carbohydrates. A high-protein, low-carb diet halved the growth rate of the tumours.
The graphs above show survival curves for female NOP mice. These mice have a genetic mutation as a result of which they automatically develop breast cancer. Of the ten NOP mice in the group that got standard feed, seven developed cancer. Of the eleven mice that were given feed containing only 15 percent carbohydrates, only three developed cancer. In addition, the protein-rich diet lengthened their life. The mice on a protein-rich diet were also a little lighter and had lower levels of glucose and insulin in their blood.
The researchers repeated their experiments when, after having injected cancer cells, they gave the mice cancer growth blockers. They noticed that the medicines worked better when the animals ate a high-protein and low-carb diet.
"A low carbohydrate, high protein diet reduces blood glucose, insulin, slows tumor growth, reduces tumor incidence, and works additively with existing therapies without weight loss or kidney failure", the researchers conclude. "Such a diet, therefore, has the potential of being both a novel cancer prophylactic and treatment."
Cancer Res. 2011 Jul 1; 71(13): 4484-93.