Poor Carb Diets & Cancer Risk

breadAn article by EJ Mundell reported that even those people who’ve never smoked could get lung cancer.  A new study suggests their risk for the disease may rise if they eat a diet rich in certain carbohydrates.  These are high glycemic index diets that trigger higher levels of insulin in the blood and tend to be heavy in refined poor quality carbs, according to one expert.

Dr. Rishi Jain, a medical oncologist at Fox Chase Cancer Center in Philadelphia, says that the glycemic load and index are methods to estimate the quality and quantity of dietary carbohydrates.  A couple of examples of these high glycemic index foods would be white bread and white potatoes.

As the rates of obesity and heart risk factors rise in the U.S., so does the number of Americans with insulin resistance, which is a precursor to diabetes.  Insulin-linked disorders are often tied to high-glycemic diets and have been implicated as potential contributors to a variety of chronic conditions that include certain cancers.  Dr. Xifeng Wu, chair of cancer prevention at the university of Texas MD Anderson Cancer Center in Houston, conducted a new study to help answer the question “if lung cancer could be one of those malignancies.”

Dr. Xifeng Wu and her team looked at the health and dietary histories of more than 1,900 people with lung cancer and more than 2,400 people without the disease.  The intake of foods with a high glycemic index, such as the white bread and potatoes, were specifically looked at by the investigators. Those people who registered in the top 5th in terms of a high-glycemic diet had a 49% greater risk of developing lung cancer versus those in the bottom 5th.  The trend was stronger when the study focused on people who had never smoked.  Those who scored highest in terms of a high-glycemic diet had more than double the odds of lung cancer compared to never-smokers who had the lowest glycemic index scores.  The findings of this study was reported in the journal Cancer Epidemiology, Biomarkers & Prevention.  

Focusing on never-smokers is important as it eliminates smoking as a confounding risk factor showing the potential role of diet in lung cancer risk.  Smoking is a major factor for lung cancer but does not account for all the variations in lung cancer risk.

Stephanie Melkonian, a study co-author says that high-glycemic diets are linked to insulin resistance, which may encourage the activity of certain cellular growth factor chemicals that are known to play a role in cancer.  Their study can’t prove the cause-and-effect and also fails to take into account the potential role of other illnesses, such as diabetes, high blood pressure or heart disease. The downstream effect of a high-glycemic diet on cellular growth factors explaining the link to lung cancer risk was agreed on by Jain.  He further stated that this association was more pronounced in nonsmokers, suggesting that increased intake of poorer quality carbs might be more detrimental in this group.

The study contributes to the growing evidence that poor dietary habits and obesity do play a critical role in cancer development.

Dr Fredda Branyon