The Yuck Factor

Why is it that some of us love broccoli and others shun it like the plague?

Some of us find the taste of broccoli revolting because we may be genetically predisposed to be “supertasters.” In addition, supertasters find intolerably bitter the compound naringin in grapefruit as well as the taste of caffeine and alcohol.

Twenty-five percent of us are supertasters; 50 percent of us are medium tasters; and 25 percent of us are nontasters. More females, Asians, Africans, and South Americans have the bitter receptor gene, TAS2R38.

Not only do supertasters have the TAS2R38 gene, but they also have twice as many fungiform papillae on their tongues (on whose sides taste receptors are located), as does the average person. Texture of food also plays a role in the supertaster’s adverse reactions to foods that they perceive as “slimy” or “spongy,” such as banana or mushroom. Dr. Linda Bartoshuk of Yale University’s School of Medicine puts it this way, “Supertasters live in a neon world of taste, while nontasters are in a pastel world.”

Ironically, the bitter taste in cruciferous vegetables such as broccoli can be traced to the same chemicals thought to provide cancer protection. Scientists have developed different types of broccoli, such as broccolini, a cross between broccoli and Chinese kale, which looks like asparagus but tastes sweeter than broccoli.

According to a 2005 study by scientists at the Kanagawa University in Japan, the “T2R gene repertoire” plays an important role in avoiding generally bitter, toxic, and harmful substances but also reflects changes in environment which result in species-specific food preferences during primate evolution. In other words, monkeys, apes, and chimpanzees are more likely to rely on their sense of taste to determine whether or not something is edible or toxic, whereas humans have a more sophisticated sense of taste and are able to comprehend that some bitter foods are nontoxic and nutritious.

There is hope in the laboratory to help supertasters enjoy healthy vegetables. In January 2003 a biotech firm, Linguagen of New York, discovered natural compounds that block bitter taste. Linda Bartoshuk of Yale University, who studies taste perception, believes this to be a study using good, solid science. Linguagen scientist Richard McGregor adds that these compounds will not mask spoiled or poisonous substances while blocking bitter tastes, because bad smells and sour tastes are conveyed to the brain through a different set of receptors and chemical messengers that warn us when food is spoiled.

This provides hope for frazzled parents: we may yet see our supertaster children munch happily on health-giving and cancer-preventing cruciferous vegetables such as the much-maligned broccoli.

Are You a Supertaster?

A test that determines the ability to perceive the bitter taste of a compound called 6-n-propylthiouracil (PROP) can determine which of us are supertasters. The test results manifest in varying degrees:

• repulsively bitter to a supertaster
• moderately bitter to a medium taster
• not at all to a nontaster

Children also taste bitter more strongly than adults, so this might explain why they are often
fussy eaters.

Solutions for Supertasters

Are there ways to overcome your child’s lack of interest in a varied and nutritious diet? For
children who perceive foods as tasting revoltingly bitter, there are several things to try:

• Add a pinch of salt to an apple slice or grapefruit segment to render it sweeter to someone who perceives it as bitter.
• Cook vegetables in lightly salted water.
• See your healthcare professional for advice on whether or not the supertaster in your family could be zinc deficient and would benefit from zinc supplementation. Zinc tablets may help to lessen a perception of bitter taste.