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This is scientific American 60 second science. I'm Christopher Intagliata.

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.

So 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,

see if it tastes bitter, you might already know your bitter status.

What Smith did is take saliva samples from 175 adults known to be at risk of cardiovascular disease.

She then did a genetic test to determine whether they had a copy of a bitter taste gene variant.

She also had him fill in a questionnaire about their eating habits.

After controlling for factors like age, gender, income, and so on,

...