Researchers at the Berkeley University of California has uncovered the key role sense of smell played in the enjoyment of food.
The findings show that the odour of what we eat may play an important role in how the body deals with calories.
According to a former UC Berkeley post-doctoral fellow now at Cedars-Sinai Medical Center in Los Angeles, Céline Riera said that study revealed that if one can’t smell his/her food, there is possibility they may burn it rather than store it.
“These results point to a key connection between the olfactory or smell system and regions of the brain that regulate metabolism, in particular the hypothalamus, though the neural circuits are still unknown.
“What’s weird, however, is that these slimmed-down but smell-deficient mice ate the same amount of fatty food as mice that retained their sense of smell and ballooned to twice their normal weight. Obese mice that lost their sense of smell also lost weight.
“In addition, mice with a boosted sense of smell super-smellers got even fatter on a high-fat diet than did mice with normal smell.
“This paper is one of the first studies that really show if we manipulate olfactory inputs we can actually alter how the brain perceives energy balance, and how the brain regulates energy balance.
“Humans who lose their sense of smell because of age, injury or diseases such as Parkinson’s often become anorexic, but the cause has been unclear because loss of pleasure in eating also leads to depression, which itself can cause loss of appetite.
The new study implies that the loss of smell itself plays a role, and suggests possible interventions for those who have lost their smell as well as those having trouble losing weight.
“Sensory systems play a role in metabolism. Weight gain isn’t purely a measure of the calories taken in; it’s also related to how those calories are perceived,” said senior author Andrew Dillin, the Thomas and Stacey Siebel Distinguished Chair in Stem Cell Research, professor of molecular and cell biology and Howard Hughes Medical Institute Investigator.
“If we can validate this in humans, perhaps we can actually make a drug that doesn’t interfere with smell but still blocks that metabolic circuitry. That would be amazing.”
Riera noted that mice as well as humans are more sensitive to smells when they are hungry than after they’ve eaten, so perhaps the lack of smell tricks the body into thinking it has already eaten. While searching for food, the body stores calories in case it’s unsuccessful. Once food is secured, the body feels free to burn it.