'Colorectal cancer and type II diabetes share a number of common factors, including obesity, so it is interesting to see the direct line between these two conditions,' said Andrew Flood, Ph.D., assistant professor in the Division of Epidemiology and Community Health at the University of Minnesota School of Public Health and the University of Minnesota Cancer Center 'In general, the idea is that if elevated insulin levels create a biochemical environment conducive to cancer growth, it provides one mechanism by which diet and lifestyle can really influence cancer risk.'
According to Flood, it is not exactly clear what aspect of diabetes is the underlying cause for this increased risk, but one hypothesis centers on the elevated concentration of insulin typically seen in people with type II diabetes. "In the early stages of the disease process, people become insulin resistant, meaning they must produce more and more insulin to regulate their blood sugar," Flood said.
"Even after frank diabetes begins, insulin levels remain chronically elevated for extended periods before the pancreas can no longer supply the level of insulin the body demands," Flood said. "If the elevated insulin is the problem, then pre-diabetics, who are also hyper-insulinemic, should also be at increased risk (for developing colorectal cancer)."
"When looking at risk of diabetes and hypertension, breast cancer survivors really should talk to their oncologist about how to lower their insulin levels," said Melinda L. Irwin, Ph.D., M.P.H., assistant professor at Yale University's School of Public Health. "The simple message is that breast cancer patients should take proven steps to lower their blood insulin levels, including exercise and eating a diet rich in fruits and vegetables and low in fat."
Uh, don't you mean a diet low in carbohydrate. Any dummy can measure their blood sugar and see that carbs raise your blood sugar/insulin, and meat/fat doesn't
When looking at just women with invasive breast cancer, the risk of death among women with high C-peptide levels was three times higher than among women with low C-peptide levels. "Our findings clearly show that C-peptide and most likely insulin, in and of itself, is a marker for breast cancer prognosis," Irwin said.
Association of C-peptide concentration with prostate cancer incidence in a prospective cohort
While studies have consistently shown that men with diabetes are at a decreased risk for prostate cancer, the reasons have been unclear. By evaluating prostate cancer data from a large, long-term cohort study, researchers at Johns Hopkins University have shown that those with high concentrations of C-peptide -- a marker of high insulin secretion that is a hallmark of diabetes -- had a measurable decrease in prostate cancer risk.
"Metabolic perturbations influence cancer risk, that much is becoming clear to us, and we are learning more about the fundamental issues in biology that guide prostate cancer development," said Gabriel Lai, a doctoral student in the Department of Epidemiology at Johns Hopkins Bloomberg School of Public Health. "One interesting possibility is that, over time, diabetics generally have less testosterone in their bloodstream than non-diabetics, which might lower risk of prostate cancer.""