High-protein Diets May Reduce Cancer Risk
(June, 2011) Eating a low-carbohydrate, high-protein diet may
reduce the risk of cancer and slow the growth of tumors already present,
according to a study published in Cancer Research, a journal
of the American Association for Cancer Research.
was conducted in mice, but the scientists involved agree that the
strong biological findings are definitive enough that an effect in
humans can be considered.
shows that something as simple as a change in diet can have an impact
on cancer risk," said lead researcher Gerald Krystal, Ph.D.,
a distinguished scientist at the British Columbia Cancer Research
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," said Prendergast, who was not involved
with the study.
and his colleagues implanted various strains of mice with human tumor
cells or with mouse tumor cells and assigned them to one of two diets.
diet, a typical Western diet, contained about 55 percent carbohydrate,
23 percent protein and 22 percent fat.
which is somewhat like a South Beach diet but higher in protein,
contained 15 percent carbohydrate, 58 percent protein and 26 percent
fat. They found that the tumor cells grew consistently slower on
the second diet.
mice genetically predisposed to breast cancer were put on these two
diets and almost half of them on the Western diet developed breast
cancer within their first year of life while none on the low-carbohydrate,
high-protein diet did. Interestingly, only one on the Western diet
reached a normal life span (approximately 2 years), with 70 percent
of them dying from cancer while only 30 percent of those on the low-carbohydrate
diet developed cancer and more than half these mice reached or exceeded
their normal life span.
and colleagues also tested the effect of an mTOR inhibitor, which
inhibits cell growth, and a COX-2 inhibitor, which reduces inflammation,
on tumor development, and found these agents had an additive effect
in the mice fed the low-carbohydrate, high-protein diet.
asked to speculate on the biological mechanism, Krystal said 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
many independent studies to promote tumor growth in both humans and
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.
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