Previously, the most consistent inverse association was found between flavonols, especially quercetin in apples and lung cancer.
While found in many plants, flavonols are found in high concentrations in apples, onions, tea, berries, kale, and broccoli. Quercetin is most plentiful in apples and onions.
The new study found that though the overall risk was reduced among the study participants, smokers who consumed foods rich in flavonols had a greater risk reduction.
According to the research, 'only a few prospective studies have investigated flavonols as risk factors for cancer, none of which has included pancreatic cancer'.
Researchers from Germany, the Univ. of Hawaii and Univ. of Southern California tracked food intake and health outcomes of 183,518 participants in the Multiethnic Cohort Study for eight years.
The study evaluated the participants' food consumption and calculated the intake of the three flavonols quercetin, kaempferol, and myricetin. The analysis determined that flavonol intake does have an impact on the risk for developing pancreatic cancer.
The most significant finding was among smokers. Smokers with the lowest intake of flavonols presented with the most pancreatic cancer. Smoking is an established risk factor for the often fatal pancreatic cancer, notes the research.
Among the other findings were that women had the highest intake of total flavonols and seventy percent of the flavonol intake came from quercetin, linked to apple and onion consumption.
It is believed that these compounds may have anticancer effects due to their ability to reduce oxidative stress and alter other cellular functions related to cancer development.
"Unlike many of the dietary components, flavonols are concentrated in specific foods rather than in broader food groups, for example, in apples rather than in all fruit," said the researchers.
This study is published in the October 15 issue of the American Journal of Epidemiology.