Foods with a high glycemic index lead to a significantly increased risk of lung cancer
Carbohydrate-containing foods with a high glycemic index (GI) such as white bread, bread rolls, cornflakes or puffed rice appear to cause a significant increase in the risk of lung cancer. In a recent study, US scientists from the University of Texas MD Anderson Cancer Center found that people with a particularly high intake of such foods had a 49 percent increased risk of lung cancer compared to people with a particularly low consumption of such foods.
The glycemic index describes how strongly carbohydrate foods affect the blood sugar level. A high GI stands for a high rise in blood sugar levels due to consumption. In their epidemiological study, the US scientists examined possible relationships between the intake of foods with a high GI and the risk of lung cancer. The results also reveal for the first time that the GI, particularly in some subgroups, such as those who have never smoked, causes a dramatic increase in lung cancer risk, the MD Anderson Cancer Center said.
49 percent increased risk of lung cancer
As part of their study, the US scientists examined the data from 1,905 patients diagnosed with lung cancer and 2,413 healthy individuals. The subjects were asked to indicate their eating habits and the researchers used this information to determine the GI and the glycemic load (specification of the GI according to the carbohydrate content of the food) of the ingested food.
On the basis of this data, the study participants were divided into five groups of equal size and a calculation of the respective lung cancer risk in the different groups followed. "We observed a 49 percent increased risk of lung cancer in patients with the highest daily GI compared to those with the lowest daily GI," said Xifeng Wu of the MD Anderson Cancer Center. Interestingly, GL, on the other hand, had no significant associations with the risk of lung cancer, which suggests that it is not the quantity but the quality of the carbohydrates ingested that influences the risk of lung cancer.
Lung cancer risk increased particularly significantly in non-smokers
When looking at different subgroups, the scientists found that the relationship between eating high GI foods and lung cancer risk was particularly clear in people who had never smoked, had squamous cell carcinoma, or had less than 12 years of education.
For example, while the smokers in the highest GI group were 31 percent higher than in the lowest GI group, the non-smokers in the highest GI group had almost twice the risk as the non-smokers in the lowest GI group . The impact of the risk factor "GI" is obviously stronger in the absence of the dominant risk factor "tobacco consumption", said Xifeng Wu.
Low level of education with an impact on the risk of lung cancer
The connection between the GI and the risk of lung cancer was particularly clear in people with a lower level of education. Those who had less than 12 years of training showed a 77 percent higher risk of lung cancer in the high GI group compared to the lowest GI group. In contrast, the risk between the two groups was only increased by 33 percent for people with more than 12 years of training. According to the researchers, the level of education served as the “proxy for the socio-economic status” of the test subjects. Low socioeconomic status is associated with more pronounced increases in the risk of lung cancer when eating foods with a high GI.
No causal relationship has been established so far
“A diet with a high glycemic index leads to higher blood sugar and insulin levels, which promote disorders in insulin-like growth factors (IGFs),” explains the study's first author, Stephanie Melkonian. Earlier studies had already suggested that a high level of IGFs could be associated with an increased risk of lung cancer, but the relationship between the GI and the risk of lung cancer has so far remained unclear.
In the current study, the researchers were now able to establish a clear connection between the GI of the food consumed and the risk of lung cancer. However, it remains unclear whether this is a causal link, Melkonian and colleagues write. Further studies are needed here to determine the causal relationship between GI and lung cancer and to investigate the underlying mechanisms.
Limit high GI food intake
While no specific nutritional recommendations could be made based on the current results, the authors suggest that a balanced diet should limit the consumption of foods and beverages with a high GI, such as white bread or rolls, cornflakes and puffed rice, in order to reduce the risk of lung cancer and chronic Lower diseases. Examples of foods with low GI are whole grain bread, oatmeal and pasta.
"The results of this study suggest that, in addition to a healthy lifestyle that does without tobacco, low alcohol and sufficient physical activity, the reduced consumption of foods and beverages with a high glycemic index can serve as a means of reducing the risk of lung cancer," Xifeng Wu emphasizes. The researchers published their results in the "Cancer Epidemiology, Biomarkers & Prevention" journal of the American Association for Cancer Research. (fp)