According to new research, cats have a much more refined sense of taste than previously believed, and they are highly sensitive to bitter flavors. The findings may help explain why cats are notoriously finicky, avoiding foods that may be fortified with bitter-tasting vitamins and minerals. Published in the journal PLOS ONE, the study also provides insight into how sense of taste evolved in all mammals, including humans.
“Cats are known as picky eaters. Now that we know that they can taste different bitters, our work may lead to better formulations of cat food that eliminate the bitter off-taste associated with certain flavors and nutrients,” explained Monell Center molecular biologist and study lead author Peihua Jiang, PhD.
The researchers examined DNA from domestic cats and identified 12 different genes for cat bitter receptors. The scientists probed the receptor cells to see if one or more of 25 bitter-tasting chemicals activated them, and it was confirmed that at least seven of the identified 12 receptors have the ability to detect one or more bitter chemicals. (The researchers feel it is likely that the other five receptors also have this ability, but that they may respond to bitter compounds not included in this particular study.)
Previous research has determined that cats cannot detect sugars. Other carnivores have also lost their ability to taste sweet things, and it is theorized that these mammals therefore have a heightened ability to detect salty and savory flavors.
Cats also seem to favor calorie-dense foods and those with different textures, which may explain why cat treats with slightly crunchy exteriors and soft interiors are especially enjoyed by most cats.
It’s been theorized that the ability to taste bitter flavors evolved to protect humans and other animals from ingesting poisonous plants, but that is now being questioned because cats primarily eat meat, not plant products. “Alternate physiological roles for bitter receptors may be an important driving force molding bitter receptor number and function,” said co-author Gary Beauchamp, PhD. “For example, recent findings show that bitter receptors are also involved in protecting us against internal toxins, including bacteria related to respiratory diseases. Bitter taste could exist to minimize intake of toxic compounds from skin and other components of certain prey species, such as invertebrates, reptiles and amphibians.” — Catnip staff