That Bitter Taste in Your Mouth

ispot-i519s1306.jpgWhich do you prefer: a succulent grapefruit or a sweet strawberry, a flaming fajita or a mild quesadilla, a strong espresso or a sweetened latte?

Taste preferences are not just choices. Favorite foods are determined by taste-receptor genes, which means the same crisp salad can taste different to many people.

John Hayes, assistant professor of food science, is studying why people experience bitter foods differently.

Throughout human history, common knowledge was a bitter taste meant that a toxic compound was present. Ancestors with ultra-refined bitter-taste receptors who avoided bitter plant toxins and compounds had an evolutionary survival advantage.

In his study, funded by the National Institutes of Health and the U.S. Department of Agriculture and published in the journal Chemical Senses, Hayes examined 100 healthy adults by having them rate the bitterness of grapefruit juice, alcohol, and espresso. Based on their diet histories and their DNA, the experiment displays how a person may be sensitive to the bitterness of grapefruit juice but not experience sensitivity toward alcohol or espresso.

Each of a human’s 25 bitter-taste genes responds to a different group of chemicals, which is why bitter-taste perception varies tremendously from person to person, affecting dietary choices and overall health. Eating fewer vegetables because of taste perception increases the risk of colon cancer. 

Bitterness is not the only taste being studied by Hayes. He notes that if more bitterness is experienced from a food, less sweetness is perceived because bitter and sweet are in opposition in the brain.

Even if your taste buds prefer French fries and ice cream, your body still loves fruits and vegetables.