Cilantro is the world’s most divisive (legal) herb.
While some consider it a divine accent to most dishes, others have described it as “soapy,” even “poisonous.” There’s a Facebook page called “I Hate Cilantro — an Anti-Cilantro Community” that boasts 11,000 likes, and beloved chef Julia Child once remarked in an interview with Larry King that it has a “dead taste.”
Why such an extreme reaction?
Researchers aren’t so sure. Studies have identified genes that might influence our appreciation of cilantro, but it’s still just might be a matter of taste — one example of a sense that continues to befuddle scientists.
“There is a field that studies taste, and a field that studies smell, but very few people study their interactions. Taste and smell are still less understood than the other sense systems,” says Yale neuroscientist Dana Small.
Sight and hearing, which seem more complex, are reasonably understood — while our everyday reactions to the foods we ingest remains a conundrum.
But then mysteries are right up science writer Mary Roach’s alley. Roach has taken on sex, death and the supernatural in her previous bestsellers (respectively “Bonk,” “Stiff,” and “Spook”), and now she’s back with “Gulp,” tackling the most taboo of subjects: our digestive systems.
Most of the book isn’t for the weak of stomach. Does one really to know what happens to our food after we swallow it? (For those who do, pick up the book for its chapters on Elvis Presley’s constipation). But unlocking the puzzle of flavor is a delicious mystery.
Our sense of taste acts as the body’s “gatekeeper,” deflecting food that may be toxic (rotten or poisonous) and inviting in nutrient-rich foods (salts, sugars and fats) that are key to survival.
There are also taste receptors located in the gut, voice box and pancreas — but only the tongue’s receptors report to the brain, where taste is discerned. The rest are believed to trigger hormonal responses and defensive reactions, such as vomiting.
Sweetness, for one, is believed to be enjoyed by nearly all humans because the brain associates it with fuel. Conversely, bitterness is often (but not universally) disliked because it can be a signal of poison.
Taste is the result of our estimated 10,000 taste buds (and their receptors) recognizing food chemicals and translating them into categories: sweet, bitter, salty, sour and savory.
This likely brings forth flashbacks of kindergarten, when we were forced to remember the diagram of the tongue mapped out into distinct locations for each taste (sweet on the tip, bitter in the back, for examples). Forget it — the diagram has been debunked. Instead, the taste buds and their varying receptors are located all over the tongue. No one area is responsible for one taste.
What’s more, the traditional five tastes (it used to be four, but savory, or “umami,” is a recent addition), might need some updating. There’s good evidence that the tongue might have a sixth taste — fat, according to a study out of Washington University in St. Louis last year.
“In five or 10 years we’ll probably be saying that there are seven to 10 tastes, instead of five,” Small says.
Other possible additions? Carbonated and metallic tastes.
However many kinds of tastes there are, our sense of it has evolved to be so integral to us that without it people often refuse to eat. They no longer recognize food as food.
Yet “taste” as we use it is not actually taste at all, it’s flavor.
Taste is born out of the taste buds; flavor wafts up through the mouth and to the olfactory system, our smell center.
In fact, 80% to 90% of what we call “taste” is actually smell-based, caused by the aromas and gases that are released into our “internal nose,” Roach says. (The fact that we have a “second nostril” is one of Roach’s favorite factoids in the book.) As we chew, aromatic gases, called “volatiles,” reach the posterior nares, or the internal nostrils, located at the back of the mouth, and then connect with the millions of olfactory receptors in the nasal cavity, which ultimately sends messages to the brain, where the flavors are discerned and food choices are made.
Think about it: Plugging your nose reduces the flavor of anything you eat. This is evident in the “jelly-bean test.” If you hold your nose and eat a jelly bean, you’ll only be able to perceive that it’s sweet, not if it’s cherry or coconut flavored.
“If your sense of smell becomes damaged in some way, taste becomes a very limited experience,” Roach tells The Post. “Drinking a glass of wine, you’d miss out on the blackberry and cherry and wood smoke and vanilla — hundreds of flavor components would be lost.”
Many weight-loss food companies manipulate this by adding sweet aromas, like strawberry or vanilla, to trick the eater’s brain into thinking they are eating things that are sweeter than they really are. The nose fools our tongue.
Flavor not only relies on taste and smell, it also utilizes temperature, touch and even pain (in the case of spicy foods).
Sight even plays a role, Roach writes. And it’s no wonder. Humans are far better equipped at processing the visual world than smells — and actually do so 10 times faster.
Our reliance on the visual bleeds into our perception of flavor, in more subtle ways than one might think. In a 2001 study of oenologists in France, a group of professional wine-tasters were asked to describe a white and “red” wine. (The red wine was no such thing, it was a white wine with crimson food coloring.) The group unanimously dropped their white wine terms and “believed they were tasting red,” says Roach.
Perhaps, most surprisingly, we also eat with our ears.
Crispiness and crunchiness are almost universally appealing (which has clearly been exploited by junk-food manufacturers) and “more so than taste or smell communicates freshness.” This has an evolutionary basis: Old produce can make you ill.
In one experiment, subjects wore headphones that muted or masked the higher frequency of the crunch of potato chips as they ate.
The result? “They rated the chips as old even though the texture had not changed,” Roach writes.
But how much of our food preferences are innate and how much are they learned? The jury is still out, but there are some interesting clues.
What is known is that even before birth, flavors are shared between mother and child through the amniotic fluid and through breast-feeding.
In one study, women who ate garlic had garlic-smelling breast milk, which didn’t deter the babies one bit. Instead, “Infants . . . sucked more when the milk smelled like garlic.”
Repeated exposures to flavors of all kinds can increase the likelihood that the baby will like the same flavors — preferences that continue into adulthood.
Finicky eaters, meanwhile, are likely not born, they’re raised, studies show.
In 1986, psychologist Paul Rozin at the University of Pennsylvania studied disgust in children aged 16 to 29 months, by asking them to eat an assortment of barely edible items. The list goes as follows, ranked highest (as in most children opted to eat it) to lowest (the least amount of children were willing to try it): cookies with ketchup, dish soap, fish eggs, “dog doo” (made with peanut butter and Limburger cheese), grasshopper and, at the lowest, human hair.
In an even earlier study, a group of orphan babies were provided a smorgasbord of foods, including liver, kidney, brains, sweetbreads and haddock. Brains and sweatbreads were not on the list of low-preference food, and the most beloved food item was, surprisingly, bone marrow.
Those two studies imply that kids younger than 3, and before cultural norms and familial predilections set in, will eat just about anything.
(It’s impossible to imagine either experiment getting approval for follow-up studies today.)
“This shows that a lot of food preferences are completely cultural,” Roach tells The Post. “You’re not born with disgust for certain foods, you acquire these senses of tastes and preferences.”
Even if disgust is already developed, however, it can be lessened or even completely overridden over time.
Roach cites one study during World War II when students at a women’s college were polled about evaporated milk (a wartime staple). Only 14% said they initially liked it. In a follow-up study, after the college served the evaporated milk for a month, that number swelled to 55%.
Price also plays a substantial factor in how food is perceived.
Cheap animal parts, like offal, are deemed inferior, and as a result less palatable to those who could afford anything else.
But all it takes, Roach points out, is one high-profile person (or a group of Brooklyn-based farm-to-the-table restaurants) to improve the standings of such food. Take sweetbreads. Now you can’t throw a rock in Williamsburg or sit through an “Iron Chef” challenge without hearing about it. Times and food preferences have changed.
Still, there may be limits to how much a person’s preferences can change. Research has shown some of our food prejudices are based in our genes — or rather these genes influence what types of receptors we have and where they are located, which influences what we like and dislike.
This seems harder to alter — but not impossible.
For all those cilantro haters out there, it might be just about repeated exposure, as Small says, “flavor preference is malleable.”
Still, it’s unlikely that cilantro haters will turn into diehard fans. According to a research, exposure may only “make a disliked food less disliked.”
scahalan@nypost.com