According to a new study published in the journal, Cancer Epidemiology, Biomarkers and Prevention, individuals whose diet consists of high glycemic index foods could have a significantly higher risk of developing lung cancer, compared to those with a healthier diet. While previous studies have demonstrated the link between high glycemic index foods and other cancers – including pancreatic, colorectal and stomach cancer – the current study is among the first to establish a connection between diet and lung cancer.
Glycemic index is a measure of how long a certain food may take to influence blood glucose levels. Patients looking to prevent or manage their diabetes are often familiar with the concept of glycemic index as it can be helpful in controlling blood glucose levels.
Foods with a high glycemic index are considered to have a greater influence on blood glucose levels, causing them to rapidly spike, compared to foods with a moderate or lower glycemic index. White bread, white rice and pineapple are all examples of high glycemic index foods, while foods such as legumes, lentils and sweet potato have a lower glycemic index.
The glycemic load of a food is linked to its glycemic index, however it also takes into account the amount of carbohydrates in food. The glycemic load gives people a more complete picture of carbohydrate levels as well as the rate at which those sugars will enter the bloodstream.
In order to better understand if a connection exists between high glycemic index food consumption and lung cancer, Dr. Xifeng Wu and his team at the Department of Epidemiology at the University of Texas MD Anderson Cancer Center, compared data collected from 1,905 patients with lung cancer, and 2,413 healthy control participants. All of the participants were asked about their diet and health history in face-to-face interviews, as part of the study.
Based on this data, Wu and his team calculated the glycemic index of the food in each participant’s diet using the 2008 International Tables of Glycemic Index and Glycemic Load Values. Based on the results of this calculation, each patient was divided into quintiles.
Participants in the highest quintile for dietary glycemic index had a 49 percent higher risk of developing lung cancer, compared to those in the lowest quintile. These participants had a staggering 92 percent increased risk of squamous cell carcinoma – a type of lung cancer which makes up 25 to 30 percent of all incidents of the lung disease.
As smoking is the most common cause of lung cancer, the researchers were interested in assessing diet-related lung cancer risk in participants who had never smoked. Wu and his colleagues found that those non-smokers in the highest glycemic index quintile had almost a two-fold greater risk of lung cancer, compared to those in the lowest glycemic index quintile.
“Although smoking is a major, well-characterized risk factor for lung cancer, it does not account for all the variations in lung cancer risk. This study provides additional evidence that diet may independently, and jointly with other risk factors, impact lung cancer etiology,” said Wu. “The results from this study suggest that, besides maintaining healthy lifestyles, reducing the consumption of foods and beverages with high glycemic index may serve as a means to lower the risk of lung cancer.”
While the calculations were based on self-reported diet information, the researchers believe the results warrant further study. “…if the results from this study are confirmed, health care providers should be made aware of the link between glycemic index and lung cancer so they can communicate with their patients and the public about dietary changes for lung cancer prevention,” said Wu.