Health

Doctors Say How We Taste Affects Health

posted: 20 November 2006 06:02 pm ET

WASHINGTON (AP) -- Woe to those who have a cold on Thursday. If you can't smell the roasting turkey, it just won't taste as good.

And if you think the brussels sprouts are bitter, well, blame how many taste buds you were born with, not the chef.

But never fear: Even after you're pleasantly stuffed from second helpings, there's a little spot deep in your brain that still gives a "Wow!'' for pumpkin pie.

How we taste is pretty complicated, an interaction of the tongue, the nose, psychological cues and exposure to different foods.

But ultimately, we taste with our brains.

"Why do we learn to like foods? When they're paired with something our brains are programmed to see as good,'' says Dr. Linda Bartoshuk of the University of Florida, a specialist in the genetics of human taste.

Sorry, brains are programmed to want fat, probably an evolutionary hangover from times of scarcity. But what's necessary for survival isn't all the brain likes. University of Michigan researchers just uncovered that eating something tasty can spark brain cells that sense actual pleasure to start firing rapidly.

More provocative, how intensely people sense different flavors seems to affect how healthy they are.

Are you among the "supertasters,'' people who shun vegetables because they find them more bitter than the average person does? Supertasters may be more at risk of developing colon cancer as a result, says a recent University of Connecticut study.

It's research that sheds light on more than how we eat at food-rich holidays like Thanksgiving. If scientists can prove those connections, it would be empowering information for people struggling to eat better year-round.

"People pile a lot of guilt on themselves,'' says Connecticut's Dr. Valerie Duffy, who is leading research into the links between inborn "preference palates'' and health.

"We know oral sensation varies,'' she adds. "Instead of making one dietary recommendation for all, can we individualize it for what people like to eat?''

One in four people is what scientists call a supertaster, born with extra taste buds. "They live in a neon taste world,'' as Bartoshuk puts it.

They find some vegetables horribly bitter, and hate the texture. They get more burn from chili peppers, and perceive more sweetness than other people. Nor do they care for fat. They tend to be skinny because they're such picky eaters.

Scientists came up with the name because these people give an extreme "Yuck!'' when given a certain bitter chemical widely used in taste research -- a chemical that certain other people, dubbed nontasters, can't even detect.

Those nontasters make up another quarter of the population. They like veggies, but unfortunately prefer heart-clogging fat, too, along with sweets and alcohol.

Everybody else falls somewhere in-between.

The good news: You can train your taste buds. The variety of foods you ate as a child, and the emotional connections to certain foods, are more important than biology in determining food preferences, Bartoshuk says.

You may trick taste buds, too.

Consider: Duffy thinks many supertasters generalize, thinking they don't like most vegetables just because broccoli made them pucker. She calls Thanksgiving a great day for supertasters to try to expand their horizons because the traditional menu is heavy on sweetened vegetables -- and sugar trumps bitterness.

Pair a bite of sweet potatoes with the broccoli, and veggie-haters might find the greenery tastes OK after all, she suggests. Or try caramelizing the leeks.

And remember, taste dulls with age -- so the Brussels sprouts you hated at 20, you may like at 50.

But taste starts before a food actually touches the tongue. Even more important than sniffing its aroma is chewing, which releases vapors up the back of the nose. You think you're tasting a flavor that really you're unconsciously smelling. It's called retronasal olfaction, and it sends flavor information along a different, more sensitive brain pathway than traditional sniffing does.

The brain, meanwhile, is busy trying to regulate competing signals from stomach hormones that say "I'm full'' with the yum factor.

Michigan researchers recently implanted electrodes into the brains of rats to track a pleasure-sensing region called the ventral pallidum. That region's cells fired in a frenzy when the rats ate a flavor, sweet or salt, that they craved, but slowly stopped as the rats got tired of eating the same old thing.

People have the same brain region, and Michigan psychologist Kent Berridge predicts it'll be in full swing at Thanksgiving dinner.

"At the moment you sit down and start to eat, that's when the firing's most intense and everything tastes delicious, more delicious than it's going to taste at any moment thereafter,'' he explains. "At the end, there are only a couple of things -- like the dessert -- that are going to make it fire again.''