Or maybe neither? Science and myth collide
You may have heard that eating bananas will attract mosquitoes to you and make you more apt to be bitten. Or maybe you've heard the opposite, that eating bananas, or just having bananas around, will repel mosquitoes. Both rumors are going around. The one claiming that eating bananas will make you more likely to get bitten is the more common one, it seems, and the explanation is usually that when your body processes the banana, the scent comes out on your skin and makes you more attractive to mosquitoes.
Bananas are such a tasty summertime treat and are also full of potassium that helps replace the electrolytes you lose when you sweat, so it would be a shame to have to give them up during mosquito season. Are the rumors really true?
The problem is that mosquitoes aren't predictable. Many things may make them bite more or less--the temperature, the color clothes you're wearing, other scents or things you've eaten. So people who've eaten bananas may sometimes report more bites, when it's coincidentally for another reason, while others may report less bites, again, for a different reason. Usually, the way to overcome such difficulties is to perform scientific studies where the variations are controlled for, but when it comes to bananas, there doesn't seem to be much published on the topic.
ABC News quoted Susan Paskewitz of the University of Wisconson, who has published many papers on mosquitoes and has studied home remedies as well as mosquitoes' biology. She acknowledged the common belief that eating bananas attracts mosquitoes, but said that a study in her lab didn't indicate it was true.
Unfortunately, I haven't been able to track down a report of the study. The University of Wisconsin's page on mosquito home remedies just says, "Bananas have not been tested. As of now, we don’t know whether avoiding bananas will have any effect on mosquito behavior."
So do bananas repel?
Some people who claim that bananas repel mosquitoes say it's because bananas are rich in Vitamin B6. The University of Wisconsin lab did test Vitamin B, taken as a vitamin supplement. As in similar studies, they didn't find that test subjects who took Vitamin B were any less attractive to mosquitoes.
Oddly, people also sometimes say that eating bananas might repel mosquitoes because bananas contain octenol. They do, but octenol is one of the odors that attracts mosquitoes. It's actually used as a bait for mosquito traps. If the folklore is true and bananas do make people attractive to mosquitoes, could the octenol be what entices the mosquitoes? If so, it's found in other things too, like citrus fruit and cheese, so bananas aren't the only source, and eating a diet without all the many things that contain it would be difficult.
A reason bananas might attract
If the rumors are true that mosquitoes seek out banana-eaters, another explanation might come from research that Dr. E. Y. Garcia did at the Manila University College of Medicine decades ago. He published a paper titled "Serotonin and norepinephrine: the 'life blood' of mosquitoes" in the June 1959 Journal of the Philippine Medical Association that showed people had higher levels of serotonin and norepinephrine metabolites in their blood after eating bananas. Mosquitoes could sense that, and because they need those chemicals too, they were more apt to bite people who had more in their blood.
That could explain why bananas make people more attractive to mosquitoes. So is the folklore true? Maybe. More studies will need to be done before scientists know for sure. But because levels of serotonin and norepinephrine rise and fall in the bloodstream for a variety of reasons, bananas aren't the only factor that make some people tastier than others. Add in all the other things that attract and repel mosquitoes, and the effect of bananas may not be that great.
By the way, if you're thinking that the serotonin from bananas will at least improve your mood, because it's a mood-regulator in the brain, well, no. The increased serotonin stays in the bloodstream and can't cross the blood-brain barrier to get to the brain.
Photo credit: Morgue File