A study led by an Indian-origin researcher from Baylor College of Medicine has found that levels of cholesterol in the membranes of hair cells in the inner ear may affect hearing.
Dr. Lavanya Rajagopalan, a postdoctoral fellow in otolaryngology at BCM, carried out this study in collaboration with researchers from Rice University and Purdue University.
"We've known for a long time that cholesterol is lower in the outer hair cell membranes than in the other cells of the body," said Dr. William Brownell, professor of otolaryngology at BCM, who is the senior author of the study report published in The Journal of Biological Chemistry.
"What we didn't know was the relationship it had to hearing," he added.
The inner ear comprises of two types of sensory hair cells, called the inner and outer hair cells. According to the researchers, it is the outer hair cells that are affected by cholesterol levels, and produce the inaudible sounds in the ear canal.
During the study, the research her team measured the mice's hearing ability by a technique that uses inaudible sound waves emitted from the ear as it reacts to external sound.
The researchers then manipulated the cholesterol levels in the outer hair cells in the mice's ear.
"Depleting the cholesterol resulted in a hearing loss. Adding cholesterol initially increased hearing but later resulted in a hearing loss. So you can change an animals hearing just by adding or subtracting cholesterol," Brownell said.
It is well known that cholesterol in the bloodstream can vary with eating habits, and that experts always recommend avoiding fatty foods to promote a healthy heart.
Brownell, however, admitted that the study had not provided any evidence suggesting any link between food habits and hearing.
"Will our hearing be affected if we continually eat greasy meals? Right now, we don't see a connection between the two," Brownell said.
"The results of the study help us understand the cellular mechanisms for regulating hearing and give us another way to potentially help those with hearing loss," he added.