A 20-year-long study looking at the links between diet and chronic diseases has discovered something peculiar: It appears older women that are sensitive to bitter flavors have an increased risk of cancer compared to women that don’t.

This research, published in the European Journal of Nutrition, is one of the findings from the UK Women’s Cohort Study, started in 1995. The team divided 5,500 women into three categories: super-tasters, tasters, and non-tasters.

"The difference in cancer incidence between the women with the highest bitter-taste sensitivity and those with the lowest was striking," lead author professor Joshua Lambert of Penn State said in a statement. "Super-tasters had about a 58 percent higher risk of cancer incidence, and the tasters had about a 40 percent higher risk of developing cancer, compared to women who were classified as non-tasters."

The goal was to see how diets, especially vegetable intake, affected risk. Bitter vegetables, such as broccoli, are known for their likely benefit in helping prevent certain conditions including cancers. The researchers initially believed that people particularly affected by the bitter taste would eat less of those and have a higher risk of cancer. And that’s the twist. It turns out that there is little variation in the amount of bitter vegetables consumed by the super-tasters compared to the non-taster.

"Our hypothesis that women with greater bitter-taste sensitivity would eat fewer vegetables, putting them at heightened risk for cancer, was perhaps too narrow a concept," Lambert added. "If you have an aversion to bitter taste, you are also less likely to drink alcohol, and alcohol is a risk factor for cancer. So, do the risks of eating too few vegetables outweigh the benefits of not drinking alcohol in terms of your overall cancer risk, or vice versa? We just don't know, yet."

As correlation does not imply causation, more work needs to be done. While the team suspects diet to be the cause between this difference, in what form this takes place is unclear. It might be small differences or major ones. There's also quality, quantity, or even more subtle parameters. The original research was done using a 217-item food-frequency questionnaire, and while it seems impressive, it doesn’t provide a complete picture.

"Maybe, if we pull back and look at the whole-diet level, we will see that women who are super-tasters have a poorer quality overall diet compared to women who are non-tasters," Lambert concluded.