Mosquitoes find their victims by smell. Specifically, their sensory organs are trained to zero in on sources of carbon dioxide and lactic acid because these chemicals lead them to warm-blooded animals, like you and me.
Chemical repellents like OFF! repel mosquitoes, but not because mosquitoes don’t like the smell of these repellents. Rather, it’s because the chemical DEET is very effective at masking the smell of carbon dioxide and lactic acid. When you’re wearing DEET, the mosquitoes can’t smell you and so they leave you alone. Natural repellents like geranium oil or citronella work the same way, they just don’t seem to be quite as effective as DEET.
Why Do Mosquitoes Like Certain People?
You’ve probably noticed that mosquitoes seem to be more attracted to some people than others. That is also because of smell—and not because mosquitoes prefer certain blood-types, as people sometimes say.
Each of us has a distinctive smell, a sort of aromatic fingerprint. There are about 400 or so different aromatic compounds that make up the human scent—and about 30 of them appear to have a masking effect. If any of these compounds happen to be prominent in your aromatic fingerprint, it tends to make you less visible to mosquitoes. Other compounds act as attractants, making certain people not just visible to mosquitoes but bona fide mosquito magnets. About 10% of the population are mosquito magnets.
So, is there anything you can do to manipulate your smell in a way that makes you less appealing to mosquitoes? Is there any truth to the old wives’ tale that eating garlic can repel mosquitoes? Actually, there is.
Does Garlic Keep Mosquitoes Away?
The smell of garlic is known to repel mosquitoes. For example, you can buy garlic sprays to put on your garden if you don’t mind the yard smelling like an Italian restaurant. Smearing your body with garlic-scented lotion is apparently effective as well, although it will probably repel more than just mosquitoes. Eating garlic may also give you some mild protection, both from the odor on your breath as well as sulfur compounds that you emit through your skin when you eat garlic.
In the end, though, scientists estimate that genetics account for about 85% of our attractiveness to mosquitoes, so we mosquito magnets may have to reconcile ourselves to our fate.
Another way to be less visible or less attractive to mosquitoes is not to exert yourself too much when mosquitoes are around. When you exercise, you give off more lactic acid and more carbon dioxide, which brings them running (well, flying). This will be the one and only time when I’ll be advising you to be more sedentary, so make the most of it!
Which Foods will Help You Avoid Mosquito Bites?
According to chemistry professor Anne Helmenstine, eating certain foods, especially foods that are salty or high in potassium, also increases the amount of lactic acid that you off-gas. I trust you know which foods are salty. As for potassium, the richest dietary sources are fruits and vegetables and I don’t think I can quite bring myself to recommend that you eat fewer fruits and vegetables—not even to save you from the mosquitoes. The farthest I’m willing to go is to suggest that you select blueberries, apples, watermelon, cucumbers, cabbage, and green peppers, which are relatively low in potassium, instead of potatoes, prunes, raisins, spinach, bananas, lima beans, and acorn squash, all of which are particularly high in potassium.
Other Ways to Avoid Mosquito Bites
You can also do yourself a favor by wearing light-colored clothing and staying indoors during mosquito rush hours, which are early morning and twilight. But if all of that, plus the string of garlic cloves around your neck and the natural repellent sprays, isn’t keeping them at bay, it’s time to bring out the big guns. Although you don’t want to be exposed to DEET any more than necessary, the dangers of mosquito-borne illnesses like West Nile virus are even more of a concern.
To limit your exposure to DEET, wear long sleeves or pants to cover up as much of your skin as possible. Then, spray a DEET-based repellant on your clothing as well as to any exposed skin. Finally, remember to wash the repellent off your skin as soon as you come inside and toss the clothes in the laundry!
Garlic may repel pests (Colorado State University)
Are you a mosquito magnet? (WebMD)
Natural Mosquito Repellents (Dr. Anne Helmenstine)
Mosquito image courtesy of Shutterstock.