Changes in taste not related to tongue nerves, say researchers
As we get older our taste preferences are known to change significantly. Despite this well known phenomena coinciding with a decrease in dietary and energy requirements as we get older, exactly how and why taste preferences shift remains unclear, according to researchers speaking at the Annual Meeting of the Society for the Study of Ingestive Behavior (SSIB), USA.
Led by Chizuko Inui-Yamamoto from Osaka Dental University, Japan, the team explained how their new study began to tackle this problem by investigating how differences in fluid intakes of rats matched up to taste nerve responses.
The team initially measured the intake of sweet, salty, umami, sour or bitter taste solutions in five age groups; juvenile, young-adult, adult, middle-aged and old-aged male rats.
Results showed that older animals had a decreased preference for sweet and umami taste and a reduced aversion to bitter taste - however the team found that these shifts were not driven by alterations in nerve activity on the tongue.
"To our knowledge, this is the first report demonstrating a reduced aversion to bitter taste in aged rats," commented Inui-Yamamoto.
She added that the team had expected to find that such changes were due to the peripheral taste system, but noted that there were no differences in electrophysiological recording of taste responses between any age groups - indicating that the altered preference was not due to changed nerve activation on the tongue.
"Our studies showed that aging elicited no changes in transmission of taste information from the tongue to the central nervous system," said Inui-Yamamoto. "Thus, our future work will investigate the role of the central nervous system in mediating age-induced changes in taste preference."
Source: Abstract presented at SSIB
"Taste preference changes in different life stages of rats."
