Taste Bud Science: Why Your Child Hates Broccoli
Discover the myths and truths behind why we — and our kids — like the foods we do
Photo courtesy of gpointstudio/Shutterstock.com
It’s lunchtime at a friend’s house. Your toddler refuses to eat the broccoli “trees” your friend serves while her son gobbles them up. You do which of the following? (A) Laugh and blame genetics: “Her daddy won’t eat green veggies either!” (B) Chalk it up to your daughter’s age: “She’s going through a phase — her tastes will mature naturally.” (C) Sigh dramatically and blame yourself: “I can’t handle the emotional battle — chicken fingers keep us all sane.”
The truth is, taste preferences aren’t a matter of nature, nurture, inheritance or experience. Your daughter’s sense of taste and flavor perception results from the fascinating combination of three things:
- Her taste buds and genetic predilections.
- Other sensory perceptions such as smell, mouth-feel, attractiveness and how it makes her feel physically and emotionally.
- Her personal experience with food, culture and her environment.
“Taste is hardwired,” says John Hayes, a professor of food science at Penn State University. “Despite all of the factors that go into food choice, you could still take a cheek swab from a kid and predict whether he is going to like veggies.”
This is because of something you inherit from your parents: a grouping of genes that make you more or less sensitive to certain tastes. Let’s get into all of these factors more deeply.
How Taste Buds Work
Those tiny bumps on your tongue are not taste buds, but papillae, which protect the microscopic taste buds growing along their sides. Infants have thousands of taste buds throughout their mouths, while adults have about half as many. These will regularly die off and be replaced, but food preferences will not change with the development of “new” taste buds.
Taste buds identify five different tastes: sweet, sour, bitter, salty and umami, which means pleasant savory taste and was named by the Japanese scientist who identified it in 1908. All babies have a strong preference for sweet foods — give them sugar water and they will smile and stick out their tongue.
“In fact, babies like it even before they’re born,” Hayes says. “Babies in the womb will make sucking motions when saccharine is injected into amniotic fluid.”
On the other hand, babies show distinct displeasure if offered bitter substances. This is a self-protection tactic. Sweet breast milk is filled with caloric goodness while bitter tastes may indicate toxins.
The intensely strong preference for sweet tastes gradually decreases as we grow, in part because we have fewer taste buds as we age. On average, children have about 10,000 taste buds — twice as many as adults.
The Bitter Gene Effect
Scientists have also identified some of the genes associated with tasting. One of these, the TAS2R38 gene, discovered in 2003, has been shown to be associated with our perception of bitterness. If your TAS2R38 gene is highly functional, you will have a stronger reaction to bitter foods, while someone who has a low functioning TAS2R38 gene might not notice bitterness at all.
According to the Genetic Science Learning Center at the University of Utah, TAS2R8 has two common alleles and at least five rare alleles. (Alleles are alternative forms of a gene.) The TAS2R8 gene’s two most common alleles are for tasting and nontasting. The tasting form is mostly dominant over the nontasting form. Since all people have two copies of every gene, combinations of the TAS2R8 gene variants determine whether someone tastes bitter foods intensely.
Lots of Taste Buds + Bitter Gene = Supertaster
People who maintain more taste buds and have a high-functioning TAS2R38 gene can be much more sensitive to tastes than others. These people makeup about 25 percent of the global population and are called “supertasters.” They have a natural dislike of anything bitter, such as cruciferous vegetables, alcohol, coffee and anything overly sweet.
If your daughter is a supertaster, she may indeed have a genetic excuse for not liking broccoli. But the story doesn’t end there.
Sense of Smell
“There are only five known tastes,” says Hiroaki Matsunami, a professor studying the genetics of olfaction in the microbiology department at Duke University. “We don’t know how many basic smells there are. Definitely more than five — probably hundreds.”
Matsunami says sense of smell is the major part of your food experience. “You can eat an orange candy or a strawberry candy and your taste buds can only sense that both are sweet,” he explains. “All the important but subtle differences between the two come from the nose.”
Plus, you probably don’t smell that orange candy the way someone else does. Scientists believe that sensory receptors in the nose differ from person to person, with some differences genetically inherited. Research into genetic smell preferences is quite new and scientists are still determining the extent of personal differences.
Crunchy vs. Crispy
“Food taste tests include much more than smell and taste,” says Lee Stapleton, a director at Sensory Spectrum Development Labs in Kannapolis. Along with teams of professional tasters, Stapleton helps companies determine what customers will like.
“Companies incorporate a lot of psychology into their marketing,” she says. “They want feedback on how all the senses are going to affect a food experience. Texture and mouth-feel are important — things like crispiness, crunchiness, stickiness and creaminess. The appearance is important as well — the color, the shape, the packaging.”
It could be that your daughter doesn’t like the softness of overcooked veggies or broccoli’s aroma or “little tree” appearance.
Even supertasters and keen smellers can learn to love foods with bitter tastes and pungent scents. Food scientist Hayes is a supertaster himself, and therefore extra sensitive to bitter tastes. But he drinks black coffee every morning and he likes beer — the more bitter, the better. This is because he associates beer with friends and experiences he had in college, and coffee with that pleasant burst of energy he gets after drinking it.
Experience with food over time is the most important ingredient of taste preference, says Susan Wyler, a licensed clinical nutritionist at Triangle Nutritional Wellness in Chapel Hill and former editor of Food and Wine magazine. Wylar, who has a master’s degree in public health from UNC-Chapel Hill, has written a number of well-received books — most recently “The Diabetes Solution,” which she co-wrote with Dr. Jorge Rodriguez, M.D.
“If a certain food is served at family celebrations like Thanksgiving, then you’ll develop a fondness for it. A lot of pleasure comes from those associations,” Wyler says.
Such associations can be negative as well. “When I was 6, I got sick right after eating watermelon, and I couldn’t eat it for 20 years,” she says. “If someone is sick, you might not want to treat them with their favorite foods.”
Cultural preferences are also the result of learned habits. Babies in Latin American countries don’t have a natural preference for spicy foods; their parents just give these foods to them early and often.
There are similar cultural differences with respect to smell. “Monell (a research laboratory) tried to make a stink bomb for the U.S. military and they found it incredibly hard to come up with a cross-culturally repulsive smell,” Hayes says.
So, your choosy daughter’s environment might include TV advertisements showing carefully photographed cheese-oozing pizzas, sweet snacks served at school or a friends’ house, or the “child’s menu” offered at nearly every restaurant in town.
The Power of Choice
What differentiates humans from animals is the ability to consider issues and make choices. Why not choose to make eating bitter-tasting foods a positive experience in your home. Here’s how.
Change the way it’s presented. “If you’ve always boiled Brussels sprouts, try roasting them with a little olive oil to bring out their natural sweetness,” Wyler says. She also suggests steaming extra vegetables to keep in the refrigerator, then tossing them with lemon juice and olive oil. You could, for example, serve broccoli with a variety of dips — hummus, honey mustard, guacamole or your favorite dressing — then let your child take control.
Model healthy eating. Believe it or not, your kids want to do what you’re doing. If you eat broccoli, that is behavior they’ll want to emulate.
Make it a positive experience. Never force your child to finish his vegetables or he’ll associate them with a negative experience. Just continue to offer broccoli, time and time again, remembering that it often takes repeated exposure to interest a child in a particular food type.
Caitlin Wheeler is a freelance writer living in Durham.
Are You a Supertaster?
Test 1: You’ll need a cotton ball, blue food dye, a piece of paper with a whole-punch-sized hole and a magnifying mirror (or a friend willing to count).
- Dip the cotton ball in blue food dye and use it to gently coat the front third of your tongue.
- Cover your tongue with the paper.
- Look in magnifying mirror at the bit of your tongue visible through the hole. Count the number of pink bumps you see within the circle.
If you have:
- Less than 1: You’re a nontaster (25 percent of the population)
- 15-35: You’re an average taster (50 percent of the population)
- More than 35: You’re probably a supertaster (25 percent of the population)
Test 2: PROP Sensitivity. True supertasters have both a large number of papillae AND a highly functional TAS2R38 gene. To see if you have the gene, look online for a “supertaster kit” that includes a test-strip sample of PROP, which is a chemical that elicits a strong reaction from supertasters.
Supertasting: Super Good or Super Bad?
If your preference and taste buds are the result of natural selection, is it safe to follow your taste inclinations? If you are a supertaster, is it all right to avoid all those bitter foods? If you are a nontaster, is it wise to let your cravings (for that pizza or protein-packed burger) dictate your meals? The answer is, probably not.
“People tend to blame their diet on their food instincts,” says John Hayes, a professor of food science at Penn State University. “But there’s always a choice involved.”
Bitter, cruciferous vegetables are good for you, whether you’re a supertaster or not, and avoiding them puts you at a higher risk for colon cancer. Sugar has been shown to lead to heart and weight problems, so it’s great if you have a natural distaste for it. Supertasters tend to be thinner (probably the result of avoiding highly sugared, greasy foods), but on the other hand, tend to develop issues with colon health.