Why Obesity Promotes CancersFriday, February 27, 2009
A new report released yesterday by the World Cancer Research Fund and the American Institute for Cancer Research states that most cancers are preventable.
Poor diet, lack of exercise, obesity and smoking account for the vast majority of cancers; the role of genetic factors is by far overrated.
Indeed, the dramatic impact of obesity on cancer is now increasingly appreciated – one in three cancers may be caused by obesity (or as a result of lifestyle factors that promote obesity). It is therefore perhaps not surprising, that large prospective studies have shown an almost 60% reduction in deaths from cancer with bariatric surgery.
But how does obesity (or poor diet) promote cancers?
New insight into the mechanistic relationship between high fat intake (not uncommon in obese individuals) and cancer come from a recent study published in BMC Cancer by Thuc T Le and colleagues from, Purdue University, West Lafayette, Indiana, USA.
Their study showed that feeding cancer-prone mice a high fat diet leads to increased fat accumulation in cancer cells, which in turn is incorporated onto the cancer cell membranes, thereby reducing cell-cell contact, increasing surface adhesion, and promoting tissue invasion by cancer cells.
They also showed that visceral adiposity and increased plasma free-fatty-acid levels (a common finding in abdominally obese individuals) are associated with early rise in circulating tumour cells and increased lung metastasis.
Thus, these studies provide insight into a mechanism directly linking increased fat intake, abdominal adiposity, and higher circulating fatty acid levels to the spread of cancer cells.
Evidently, much of cancer should perhaps now be best classified as a “lifestyle disease” (a term often used to “trivialize” obesity).
Prevention and treatment of obesity may prove to be the most effective “cure” for cancer after all.
Hat tip to Jacob Berkowitz for bringing the latter study to my attention.