Eating certain herbs and spices ‘could stop mosquitoes biting you’
Sarah KnaptonSat, May 20, 2023 at 4:19 AM GMT+8·3 min read
Sweet basil, rosemary and sage contain eucalyptol which may ward off mosquitoes - Kittikorn Nimitpara/Moment RFMore
Eating herbs and spices could be the key to preventing mosquitoes from biting, a study suggests.
Experts from Johns Hopkins University set up an intricate trial in an ice rink-sized testing arena in Zambia to find out which people are most attractive to mosquitoes.
In one experiment the team asked six people to sleep in single-person tents which had a pipe pumping out the nightly aroma of the occupant onto a monitored mosquito landing pad.
They found that the mosquitoes were consistently drawn to the smells of people emitting more carboxylic acids - probably produced by skin microbes - but were repelled by a person who had elevated levels of eucalyptol.
Eucalyptol, an aromatic component of many plants, is found in mugwort, sweet basil, rosemary, sage and cardamom and is a common ingredient in toothpaste and mouthwash.
Dr Conor McMeniman, Assistant Professor at Johns Hopkins Malaria Research Institute, said: “Our study hints at the notion that high levels of eucalyptol in your body scent may make you less attractive to mosquitoes.
Deodorising agent
“Interestingly all humans whose body scent we analysed in this study seemed to emit some eucalyptol. However, the person that was least attractive to mosquitoes had higher amounts of the chemical in their scent signature.“We think this person likely obtained this compound from plant-based foods in their diet (eucalyptol is abundant in many different herbs and spices including mugwort, sweet basil, rosemary, sage and cardamom); but it is also possible it could also have been from exogenous products as eucalyptol is also a common ingredient in toothpaste and mouthwash.”
Experts think that as well as producing a strong off-putting aroma, eucalyptol may also act as a deodorising agent which neutralises or masks the other chemicals that attract mosquitoes, such as carboxylic acids.
Most studies of mosquito preference have been performed in confined laboratory settings that do not represent how the insects act in the wild.
The testing arena contained a ring of evenly spaced landing pads that were heated to human skin temperature and baited with carbon dioxide and body odour.
200 hungry mosquitoes
Each night, the researchers released 200 hungry mosquitoes into the arena and monitored their activity using infrared motion cameras.Because mosquitoes typically bite humans between 10pm and 2am, the team wanted to assess whether the insects were more attracted to certain types of sleeping humans.
Dr McMeniman said: “To definitively conclude that high levels of eucalyptol in one’s diet would ward mosquitoes away, would require a clinical trial with larger numbers of human volunteers which we didn’t perform here.
“However, such studies in the future are now possible with this new system we have developed in this study to rank human attractiveness to mosquitoes at high-throughput.
“In the future we hope to expand our study to collect more detailed dietary information of participants and examine in finer detail the role that diet and the human skin microbiome play in influencing how we smell to mosquitoes; including other species of nuisance biting mosquitoes we all encounter in our backyards around the world.”
The research was published in the journal Current Biology.
Source:https://news.yahoo.com/eating-certain-herbs-spices-could-201944379.html
