Cancer
Low-protein diet might reduce cancer risk
By Ben Wasserman - foodconsumer.org
Dec 14, 2006 - 2:14:41 PM

A low-protein diet may lower cancer risk in humans, according to a new study published in the December issue of American Journal of Clinical Nutrition.

Vegetarians and distance runners have lower levels of hormones and other compounds that are implicated in development of certain cancers than those who were sedentary and ate a typical American diet, the study found.

In the study, Dr. Luigi Fontana, an assistant professor of medicine at Washington University in St. Louis and colleagues tested the levels of hormones and other substances in 21 vegetarians who had practiced vegetarianism for at least two years, 21 long-time endurance runners and 21 others who were sedentary and ate a typical American diet high in meat and diary. All volunteers were middle-aged adults at the same age.

The researchers noticed that the vegetarians ate less protein than the amount recommended (0.8 g per kg body weight) while the Sedentary volunteers ate more than the recommended amount.

While both the runners and vegetarians had low levels of certain risky hormones and other substances, the vegetarians on a low-protein diet had a significantly lower level of insulin-like growth factor 1, known as IGF-1, which promotes cell growth and multiplication.   High levels of IGF-1 have been linked to elevated risk of prostate cancer, breast cancer and colon cancer.

The study also found that even though both the vegetarians and runners are equally lean, the runners have a high level of IGF-1, indicating that the body mass index may not be relevant when it comes to the IGF-1 level and it is the diet that makes the difference.

A diet with high animal protein has been known to be a cancer risk in animals, according to the China Study authored by Dr. T. Colin Campbell, emeritus  professor from Cornell University, who found plant protein does not pose as much risk as animal protein even at high doses.

Dr. Fontana suggested in a statement, cited by Reuters.com, that people should reduce consumption of red meat and increase use of fruit, vegetables, fiber-rich grain products, beans and fish to lower the hormone levels in the body, which may in turn reduce the cancer risk.