Thinking about starting a low-carbohydrate, high-protein diet? Something as simple as a change in diet can have an impact on your cancer risk, said Gerald Krystal, Ph.D., a distinguished scientist at the British Columbia Cancer Research Center.
Krystal led research in mice that shows low-carbohydrate, high-protein diets have the ability to reduce the risk of cancer and slow the growth rate of tumors already present. The findings will be published in the July 1, 2011 edition of "Cancer Research", a journal of the American Association for Cancer Research.
"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," said George Prendergast, Ph.D., CEO of the Lankenau Institute for Medical Research, who was not involved with the study.
Krystal and colleagues conducted the study in mice, but agreed that the strong biological findings are definitive enough that an effect in humans can be considered.
In the study, mice were implanted with human tumor cells or mouse tumor cells and assigned to one of two diets. The first diet was a typical Western diet containing about 55 percent carbohydrate, 23 percent protein and 22 percent fat. The second diet was similar to the South Beach diet but with higher protein levels: 15 percent carbohydrate, 58 percent protein and 26 percent fat. The results showed the tumor cells grew consistently slower on the South Beach-like diet.
Mice genetically predisposed to breast cancer showed some of the most noteworthy results. Those who were on the Western diet developed breast cancer within their first year of life while the low-carb, high protein-fed mice did not. Only one mouse fed the Western diet reached a normal lifespan of approximately 2 years; 70 percent died prematurely from cancer. Thirty percent of the mice eating the low-carb diet also developed cancer however, more than half reached or exceeded the normal life span.
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. Krystal said that tumor cells, unlike normal cells, are fueled by glucose. Restricting carbohydrate intake can significantly limit blood glucose and insulin, a hormone shown in many independent studies to promote tumor growth in both humans and mice.
As long ago as 1982, the National Research Council published a report called Diet, Nutrition, and Cancer, showing the evidence linking specific dietary factors to cancer of the breast and other organs.
The report pointed out that Asian countries’ breast cancer rates are traditionally some of the lowest in the world, in part because of their traditionally low-fat diet full of fresh vegetables, rice, fish, soybeans, seaweed, and other sea vegetables. Western countries, which have diets are higher in fat, saturated fats and carbohydrates, have cancer rates that are many times higher. However, when Japanese girls were raised on Westernized diets, their rate of breast cancer increases dramatically, according to the report.
In another study looking at diet and breast cancer rates, researchers in Seoul, Korea, analyzed lifestyle characteristics of 5,000 breast cancer patients admitted to the Asian Medical Center for breast surgery between 1989 and 2004. They found that breast cancer rates among Korean women are increasing faster than the world average. Researchers blamed an increase in risk factors, including the consumption of higher fat foods, which, according to the Korean Breast Cancer Society, increased significantly between 1996 and 2000.
The Korean study noted other changes that reflect lifestyles of Westernized nations including earlier menarche (perhaps due to diet changes), a delay in childbearing, insufficient breastfeeding, late menopause, and obesity.
Lynette Summerill is an award-winning writer who lives in Scottsdale, Arizona. In addition to writing about cancer-related issues for EmpowHER, her work has been seen in newspapers and magazines around the world.
Sources:A Low Carbohydrate, High Protein Diet Slows Tumor Growth and Prevent Cancer Initiation. Victor W. Ho, Kelvin Leung, Anderson Hsu, Beryl Luk, June Lai, Sung Yuan Shen, Andrew I. Minchinton, Dawn Waterhouse, Marcel B. Bally, Wendy Lin, Brad H. Nelson, Laura M. Sly and Gerald Krystal. Cancer Research, July 2011.
National Research Council. Diet, Nutrition, and Cancer. Washington, DC: National Academy Press, 1982. Study accessed at www.nap.edu/books/0309032806/html/
Son BH, Kwak BS, Kim JK, et al. Changing patterns in the clinical characteristics of Korean patients with breast cancer during the last 15 years. Arch Surg. 2006 Feb;141(2):155-160. Abstract accessed at http://www.ncbi.nlm.nih.gov/pubmed/16490892
Reviewed on June 17, 2011
Edited by Alison Stanton