It is known that high-fat foods increase the risk of contracting cardiovascular diseases and diabetes, as well as other chronic illnesses. However, a recent study from Florida State University (FSU) found that an unhealthy, high-fat diet also causes impairment in the olfactory system or the sense of smell.
The study, led by Dr. Nicolas Thiebaud and biological science professor Debra Ann Fadool, established an association between consumption of high-fat foods with changes in neuronal proliferation and the normal apoptotic cycle, which impacts olfactory perception. The study entitled Hyperlipidemic Diet Causes Loss of Olfactory Sensory Neurons, Reduces Olfactory Discrimination, and Disrupts Odor-Reversal Learning was conducted together with the researchers from the University of West Georgia, Larry A. Ryle High School in Kentucky, and the FSU Department of Mechanical Engineering and Institute of Molecular Biophysics.
Laboratory mice were fed a high-fat daily diet over a six-month period and were taught to associate an odor with a reward (water). Data collected showed that the group of mice that had a high-fat diet were slower to learn the association than other mice who were fed a normal diet. When a new odor was introduced, the high-fat diet mice group could not adapt easily. It was found that the mice who had daily high-fat diets had a reduction in smell capabilities because 50 percent of the neurons responsible for the functions of the olfactory system were non-functional when decoding odor signals.
This study did not include any human tests, and there may be a significant difference in results. It is also important to note that the test done on mice included a high-fat diet, and not a high-sugar one. There is a difference between resulting obesity from high-fat diets compared to obesity from high-sugar diets, and the consequences on the olfactory system may not be the same. Other related studies include how the olfactory system affects our preference for what we ingest, and problems with the olfactory system result to unhealthy food choices.