If you have heart disease,your doctor might tell you,eat more vegetables.

A tactic that has limited success.

"Getting people to change their diets is actually pretty hard.

These are lessons I would give over and over again.

And I would think,'Why is this so hard to do?

'" Jennifer L. Smith is a nurse researcher at the University of Kentucky who now has a preliminary answer about why change is so hard:it might depend on your genes.

Specifically,whether or not you're genetically predisposed to perceive bitterness—and therefore bitter veggies.

"So broccoli is definitely one of them.

They tend to be cruciferous vegetables,like broccoli,cauliflower,cabbage,brussels sprouts,asparagus." If you ever took that test in science class where you put a piece of paper on your tongue to see if it tastes bitter,you might already know your bitter status.

Smith took saliva samples from 175 adults known to be at risk of cardiovascular disease.