Move over sweet tooth, here comes the fat tongue.
A new study suggests that some people may have a sixth sense when it comes to tasting fatty foods, which may explain why some folks have a harder time resisting fried foods and other fatty treats.
The results show that rats and mice have a special sensor on the tongue that detects and tastes fat in addition to other known taste sensors, such as sweet, salt, sour, and bitter.
Researchers say that until recently it was thought that mammals could only sense fat in the mouth through clues provided by its scent and texture. But the possibility of an additional taste sensor for fat has been suggested because many animals display a spontaneous attraction for fats.
A Fat Taste Bud?
In the study, published in the Journal of Clinical Investigation, researchers identified a protein called CD36 (also known as fatty acid transporter, FAT) as the first candidate for the fat sensor in mice and rats.
First, researchers found that the protein is located alongside taste buds on the tongue, which suggests that it may play a related role.
Second, experiments showed that in mice missing the gene that makes CD36, there was elimination of the natural preference for fatty foods as compared with a normal group of mice. Mice without the gene did not differentiate between a fatty solution and a nonfatty one, while those with the gene preferred the fatty one.
Finally, stimulating CD36 proteins on the tongue with the fatty acids found in fats triggered increases in stomach secretions used to digest fats. This was evident in a test comparing normal mice with mice missing the CD36 gene.
Researchers say the results suggest that an alteration in this fat perception system may play a role in how much fatty food people eat and the risk of obesity.
By Jennifer Warner, reviewed by Louise Chang, MD
SOURCES: Laugerette, F. Journal of Clinical Investigation, Oct. 20, 2005, online advance edition, vol 115. News release, Journal of Clinical Investigation.