The link between lung cancer and smoking has been known since the ‘50s, with many quitting cigarettes because of the serious health dangers posed. However scientists have now discovered that foods with a high glycemic index increase the risk of lung cancer, too. These include carb favorites like bread, corn flakes, and puffed rice.
“We observed a 49 per cent increased risk of lung cancer among subjects with the highest daily GI compared to those with the lowest daily GI,” lead study author Dr. Stephanie Melkonian, of the University of Texas MD Anderson Cancer Center, said.
The reason behind the high GI intake and lung cancer link is that the foods, which are defined by how quickly blood sugar levels are raised after a meal, trigger high levels of blood glucose and insulin. These high levels then increase a type of hormone called Insulin-Like Growth Factors (IGFs). Raised levels of IGFs have been linked with a higher risk of lung cancer in the past.
“Previous research suggests increased levels of IGFs are associated with increased lung cancer risk,” Dr Melkonian said. “However, the association between glycemic index and lung cancer risk was unclear.”
There is some good news though: Melkonian’s team found cutting out foods with a high GI content reduces a person's risk of lung cancer.
Whole wheat and pumpernickel bread, rolled or steel-cut oatmeal, and wholemeal pasta all boast a low glycemic index, making them ideal swaps.
To get their results, scientists looked at 1,905 patients newly diagnosed with lung cancer, finding there was a higher risk of lung cancer in patients with the highest daily GI.
It’s important to note that not all carbohydrates are cancer causing. As the study found, glycemic load (a measure of carbohydrate quantity) had no significant association with lung cancer risk. This suggests it is the average quality, instead of quantity, of carbohydrates consumed that may modulate lung cancer risk.
Results have been published in the journal Cancer Epidemiology, Biomarkers & Prevention.
The study is the largest ever to investigate the potential link between glycemia index and lung cancer, as well as being the first piece of research to show GI was more significantly associated with lung cancer risk in specific subgroups—including people who had never smoked.