While the study involved mice, who have a greater incidence of cancer compared to humans, the mechanisms of the study are entirely plausible, and likley do also apply to human physiology. The study authors noted that tumor cells feed on glucose, far more than do normal cells.Based on this, two diets were supplied to mice that had been implanted with either mouse or human tumors.The first diet was a typical Western diet, the type often suggested as being the best to maintain health by many health professionals. This diet consisted of 55 percent carbs;23 percent protein; and 22 percent fat. The second diet was a lower carb plan, consisting of 15 percent carbs;58 percent protein; and 26 percent fat. Since calorie restriction is known to slow tumor growth, the study authors ensured that both diets contained the same number of calories by increasing the protein intake of the low carb plan. They didn't want to increase the fat content, since a higher fat intake is also linked to faster tumor growth.
In another part of the study, mice genetically engineered to have breast cancer were placed on the same two diets. Half the mice on the Western diet developed breast cancer within a year, while none of the mice on the low carb plan showed any signs of cancer.Only one of the mice on the Western diet reached a normal mouse lifespan of two years,with 70% of them dying from cancer. In contrast, 30% of the low carb mice developed cancer, yet more than half exceeded the normal mouse lifespan. When a drug that inhibits mTOR and a common anti-inflammatory drug, Celebrex, which is a COX-2 inhibitor, were added to the diets, the preventive effects against cancer were even stronger. mTOR is a protein that stimulates cellular growth, and also dictates muscle protein synthesis. The COX-2 drug lowers inflammation, which is a core effect of cancer.
So why did the low carb diet show such preventive and tumor-slowing effects? As noted, tumor cells depend on a large supply of glucose in order to fuel growth and spread, and lowering glucose through decreased carb intake blunts this effect. In addition, higher glucose levels promote an increased release of insulin, which is also known to promote tumor growth. Finally, a low carb diet helps to prevent obesity, which causes the inflammation that is at the root of all types of cancer. But what is most intriguing about all this is that the diets that are usually recommended to preserve health are actually more potent at promoting cancer and heart disease, the two leading causes of death, compared to the often condemned low carb diets.
Ho, et al. A low carbohydrate, high protein diet slows tumor growth and prevents cancer initiation.Cancer Research 2011;71:4484-93.
©,2013 Jerry Brainum. Any reprinting in any type of media, including electronic and foreign is expressly prohibited.
