WEDNESDAY, Nov. 7 (HealthDay News) -- Adding to evidence that lifestyle affects disease progression, new research suggests that late-stage colon cancer patients face a higher risk of cancer recurrence or death if they consume a diet rich in carbohydrates.
The same seems to be true of patients whose diet is generally at the higher end of so-called glycemic load intake levels, which includes high consumption of items such as breads, potatoes and baked goods, the researchers said.
Both findings build on previous studies that observed that obesity and sedentary behavior may increase the risk of cancer recurrence and death. Those investigations noted that excess weight and insufficient exercise have a negative impact on insulin levels, which in turn increases the risk for hyperinsulinemia (a condition in which patients have too much insulin in their blood) among patients who have survived an initial bout of colon cancer.
What's more, the authors of the new study, led by Dr. Jeffrey Meyerhardt, of the Dana-Farber Cancer Institute in Boston, suggested that their findings may strongly reflect such concerns about obesity and lack of exercise, given that those who eat excessive carbs and high-glycemic diets are more likely to carry excess weight.
Meyerhardt's team reported their findings in the Nov. 7 issue of the Journal of the National Cancer Institute.
"Given that patients who consume high glycemic loads or carbohydrates after cancer diagnosis may have consumed a similar diet before diagnosis, we cannot exclude the possibility that individuals with these dietary exposures acquire tumors that are biologically more aggressive," Meyerhardt said in a journal news release.
To explore the potential connection between diet and colon cancer survival, the investigators analyzed data from more than 1,000 stage 3 colon cancer patients.
All of the patients had provided detailed information regarding their diet over a six-month period during enrollment in a chemotherapy treatment study, as well as for another six months after that study was completed.
After assessing the impact of carbohydrates, fructose (a type of sugar) and glycemic loads and indexes on colon cancer development, Meyerhardt's team concluded that there was a cancer connection with carbohydrates and glycemic load.
An accompanying journal editorial by Dr. Neal Meropol and Dr. Nathan Berger -- both from the division of hematology and oncology at University Hospitals Case Medical Center and Case Western Reserve University School of Medicine in Cleveland -- pointed out that Meyerhardt's findings are in line with the well-known notion that cancer cells are actually avid sugar consumers.
However, Lona Sandon, a registered dietician and assistant professor of clinical nutrition at the University of Texas Southwestern Medical Center at Dallas, cautioned against reading too much into the new study findings.
"One of the most important things about this study is that it is an observational study," Sandon said. "It does not prove cause and effect -- only a relationship."
"We cannot make dietary recommendations based on this study alone," she added. "And it is insufficient to change [dietary] recommendations that already exist; that is, to maintain a healthy weight, increase physical activity and choose a healthy diet with limited excess sugars."
For more on colon cancer, visit the U.S. National Cancer Institute.
-- Alan Mozes
SOURCES: Lona Sandon, M.Ed., R.D., assistant professor, clinical nutrition, University of Texas Southwestern Medical Center at Dallas; Journal of the National Cancer Institute, news release, Nov. 7, 2012
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