Q. Mosquitoes seem to bite me more than other people. Does this mean I might need more B vitamins, or that I’m eating too much of certain foods?
A. It is another confirmation of our biochemical individuality that the attractiveness of different people to mosquitoes varies greatly. There is evidence that genetics accounts for much of this difference, and you may not be able to do anything about that. There are hundreds of compounds released from the skin and breath that mosquitoes use to identify you as their dinner, so your odor is as distinctive to them as your fingerprint.
Concern about the West Nile virus has catalyzed the search for ways to make us humans less attractive to mosquitoes. The odors from carbon dioxide in the breath and skin, and lactic acid in sweat are the two best studied of these compounds. These may be detectable by mosquitoes from as far as 100 feet away. In addition, mosquitoes also seem to target people who produce large amounts of certain other substances such as uric acid and cholesterol byproducts that apparently make mosquitoes swarm in.
Plenty of natural mosquito repellants are on the shelves, but their effectiveness is subject to controversy. The individual differences in our attractiveness to mosquitoes make research difficult and personal experiences unreliable. Many of these “home remedies” are at least harmless, so if you find one that works for you it doesn’t matter whether or not it works for anyone else. The list of harmless solutions includes eating lots of garlic or onions and/or taking vitamin B1. These will impart a sulfur odor to your body that hopefully helps keep mosquitoes away. Avoiding bananas may or may not help. The essential oils of some plants and spices have been reported to repel mosquitoes. These include citronella, cedar, verbena, pennyroyal, geranium, lavender, pine, cinnamon, rosemary, basil, thyme, allspice, and peppermint. When tested, most of these essential oils gave only short-lasting protection. Preliminary studies show oil of eucalyptus may offer longer-lasting protection. One of the best natural insect repellents may be real vanilla (not vanilla extract), and it certainly smells better than many repellants. This is the pure vanilla that is sold in Mexico, although some health food stores carry it or can order it for you.
In a study published in The New England Journal of Medicine in 2002, researchers compared commercial mosquito repellents in head-to-head laboratory tests. The least effective product was a wristband treated with DEET, the most common commercial repellent. The problem seems to be that DEET and other such mosquito repellents only work on the skin where it is applied directly. Mosquitoes are happy to bite skin only a couple of inches away from where the repellent has been applied.
As with many health concerns, prevention, in terms of avoidance of the areas mosquitoes like, is often the answer to the problem. While any water source is a potential breeding ground for mosquitoes, they much prefer stagnant water, so biting tends to increase around such a water source. Floral fragrances from perfumes, soaps, lotions, and hair-care products may also draw in mosquitoes. If you have a few hundred dollars to invest, there are portable mosquito traps that emit carbon dioxide and other chemicals that are supposed to lure mosquitoes away from people and into the trap.
This article appears in August 27 • 2004.