Obese people are less sensitive to the taste of food than usual but they could regain a normal sense of taste after losing weight, according to a new study conducted by the Department of Food Sciences at Cornell University, in the USA) on mice.
Obese mice presented fewer taste buds
The scientists fed a group of mice with a diet with 58% fats and, additionally fed the second group with a normal diet of 14% fats. After eight weeks, the mice which were forced to follow the unhealthy diet weighed a third more and had 25% fewer taste buds in on their tongues than the others.
“We did not know if obese people are born with a weaker sense of taste and therefore are predisposed to gain weight, or if everyone is born with a similar sense of taste and weight gain triggers the loss of taste sensitivity,” admitted Robin Dando, the study’s leading author.
Mice normally replace taste buds every 10 days, in a process that is governed by the programmed death of old cells and by the differentiation of new receptors from stem cells.
However, in obese mice cell death is accelerated while the number of stem cells falls, which slows down the regeneration of the taste buds.
Inflammation, which is caused by overweight and obesity is the culprit
The team points out that the loss of taste is a consequence of the mild, chronic, and systemic inflammation that obesity and overweight cause.
One cause of inflammation is TNF-alpha, an immune molecule that sends inflammatory signals through the body and activates cell death processes. By injecting this molecule directly into the tongue of the regular-weight mice, the animals lost taste buds without gaining weight.
“The results point to new therapeutic strategies to treat sensory dysfunction of taste in obese people,” adds the researchers. “If someone becomes more sensitive to taste, it is plausible that they do not need so much sugar, fat or salt in their diet, and then they can adopt better eating habits,” Dando concludes.
In conclusion, the scientists have proven on animal models that obese people are less sensitive to the taste of food.