S u m m a r y :
Obesity reduces the number of taste buds in the tongue, thereby weakening the sense of taste, says a new study published in PLOS Biology.
Obesity reduces the sense of taste through the loss of the tongue’s taste buds, says a recent paper authored by a team of scientists from Cornell University. This research builds up on previous ones that suggest weight gain lowers our sensitivity to the taste of food. The new finding is pointing at a potential “human mechanism for getting fat”, suggests one of the researchers, Robin Dando.
Dando and his colleagues studied how mice fed with a high-fat diet grew obese, in the aftermath of which they lost around 25% of their taste buds. These mice were, then, subjected to an obesity-triggered metabolic malfunction: they were inclined to eating more, locking themselves in a cycle of obesity.
The Cornell University team of investigators compared normal and obesity-resistant mice. When on a high-fat diet, the normal mice would gain 30% of their body weight while the latter would not experience any significant change in their weight in spite of consuming the same unhealthy diet as their counterparts. Furthermore, the normal mice also lost taste buds while the obesity-resistant ones still had their normal taste bud abundance. The team interpreted these results as implying that obesity, and not the exposure to fats, triggered the metabolic response of taste bud loss.
“Evidence suggests that obesity from an unhealthy diet results in a powerful [metabolic] inflammatory response,” Dando said. “In mice, this response disrupts the balance of taste bud renewal, reducing how many mature taste buds these mice have. This research provides new clues about how humans might become obese and suggests a novel approach to combating obesity – looking at the taste bud itself.”
Moreover, past research on the same topic shows that obese people report a reduced sense of taste, which might have caused them to eat more.
“Combining those results with this new work, it’s an interesting takeaway. Our obese mice would not be getting as much input from taste. If the same taste loss happens in obese humans, it’s plausible these people would be driven to eat more, or at least eat a more intensely tasting version of whatever they were eating,” Dando said.
The average number of taste buds in humans is 10,000; these cells are renewed one to two times per month. The evidence suggests that this process is facing interference from obesity: the resulting weakened metabolism from such weight gain would be impairing the taste bud renewal and decreasing the number of taste buds, leading to the obese person consuming more, which would cause more taste bud loss, and thus goes the vicious cycle.
The good news, thankfully, is that the taste buds may be restored. Previous research indicates that the negative effect can be reversed with weight loss. How does this happen, though, remains unclear.