Menthol and Sucrose are effective remedies for cough and they independently reduce coughing, a new study says.
The researchers say that this might be the reason why syrups that do not have any ingredient to reduce cough work just as well as syrups that do.
"This is the first study to empirically show that sweet taste reduces cough. This also is the first study to show that menthol alone can reduce coughing in response to a cough-eliciting agent," said Paul Breslin, Monell sensory scientist and author of the study.
For the study, participants were made to sniff capsaicin from chili peppers. The participants had to inhale different concentrations of capsaicin till they coughed at least 3 times in 10 seconds. The concentration of capsaicin that induced coughing was marked as coughing threshold. An increase in cough threshold means that the desire to cough is reduced.
As a part of the study, the subjects had to hold water or sucrose solution in their mouths before inhaling capsaicin. The researchers found that sweet sucrose solution increase cough threshold by 45 percent. They found that bitter sucrose solution did not have the desired effect on cough.
To test the efficacy of menthol, the participants were made to inhale air that was saturated with menthol or fresh air before inhaling capsaicin. They found that menthol increased coughing threshold by 25 percent.
The effect of menthol in reducing cough might be more than placebo effect. According to a study, inhaling menthol effectively reduces coughing.
"Individuals with a weak cough reflex are at increased risk of pneumonia and of choking. Conversely, many acute and chronic conditions involve frequent coughing, leading to 30 million health care visits annually, with billions spent on over-the-counter medications and billions more lost due to reduced productivity," said Paul M. Wise, Ph.D., a sensory psychologist at Monell and lead author of the study.
Researchers add that adding menthol to cigarettes will make the smoke more tolerable for beginners and reduce coughing by making the body's defense mechanism less sensitive to smoke.
"Menthol may dull the sensitivity of sensory nerves in the airways and thereby actually disable an important reflex mechanism that would otherwise protect smokers from the chemical and particulate irritants present in cigarette smoke," said Wise.
The study is published in the journal Pulmonary Pharmacology and Therapeutics.