“And for my next trick . . . I think I’ll eat some shellac.” That line always gets a buzz out of the kids when I “perform” at an elementary school. I think they do like the color changes and the explosions, but they really come alive when they think you’re going to eat something “gross.” And the sticky secretion of the tiny Indian “lac” bug seems as gross as you can get.
Indeed, shellac is the resinous secretion produced by the female of the Laccifer lacca species. This little insect spends its whole life attached to a tree, sucking its juices, and converting them into the familiar sticky substance that has long been used to provide a glossy protective coating on wood. It takes a colony of about 150,000 insects to produce a pound of the resin, which has a variety of other applications ranging from stiffening hats to making buttons. The first hair sprays had shellac as their main ingredient, and the first phonograph records were made of this material. Shellac is soft and flows when heated, but becomes rigid at room temperature.
So you can see why, after hearing the apparently distasteful origins of shellac, a young audience would be excited by the prospect of my eating an “insect discharge.” I must admit, though, they seem a tad disappointed when, instead of dipping into a can of varnish, I plop a shiny piece of gum into my mouth! The explanation that the gum is coated with shellac usually elicits the expected “yucks.” In the food industry, shellac is often referred to as “confectioner’s glaze,” and can be used to give a protective, glossy coating to gum, candies, jelly beans, and ice cream cones. Since shellac is insoluble in water, it prevents the product from drying out by forming a layer impermeable to moisture. Citrus fruits and avocados are sometimes treated with shellac for this very reason.
Like any food additive, shellac is subject to rigorous safety regulations. Animal tests have shown no adverse reactions, and it has a long record of safe use in humans. This is not surprising, since the components of shellac—mostly a mixture of organic acids and esters—are found in a wide range of foods. What is surprising is people’s—particularly children’s—aversion to eating anything that derives from insects, with the possible exception of the sticky regurgitation of the honeybee.
Of course, just because honey happens to be purified bee barf doesn’t mean we shouldn’t eat it. Just as there is no reason to give up candies or gum because they may be coated with a bug secretion. But there certainly are reasons to limit intake of such sweets. For one, bacteria in the mouth can convert sugar to acids that cause tooth decay. Enter the “sugarless” gums and candies! Actually, they aren’t really sugarless. They contain either sorbitol or xylitol, which are basically also sugars. Xylitol is particularly interesting. Its source may not be quite as unusual as that of shellac; it comes from corncobs, peanut shells, or birch bark.
The appeal of xylitol is not that it provides no calories. Actually, it does provide calories, although not as many as sugar. That’s because xylitol is very slowly absorbed through the intestinal wall, and much of it is excreted. This is of real benefit to diabetics, since it means that the rise in blood glucose and insulin response associated with sugar is significantly reduced. But perhaps the most seductive feature of xylitol is that the Streptococcus mutans bacteria in our mouth cannot convert it to acids, and therefore, while it sweetens almost like sugar, it does not contribute to the formation of cavities. In fact, not only does xylitol not promote tooth decay, it actually reduces its occurrence. A recent study examined the effects of chewing gum sweetened with xylitol. Almost 300 eight and nine year olds were assigned to either a “no gum” control group, or a xylitol group where one stick of gum was chewed for five minutes three times a day on each school day for two years. It turned out that the gum chewers had significantly lower progression of tooth decay and less plaque on their teeth.
There is still more about the potential benefits of xylitol. One of the most common medical problems in young children is a bacterial or viral infection of the middle ear known as acute otitis media. It usually develops as a complication of the common cold when viruses reach the middle ear through the Eustachian tube from the throat. The viral ear infection is often followed by a bacterial infection. There is pain, high temperature, and the risk of complications, including infection of surrounding bone, hearing loss, or even the inflammation of the covering of the brain, known as meningitis.
The usual treatment is with amoxicillin, which works well. But obviously, it would be better to prevent the infection in the first place and cut down on the use of antibiotics. This may be possible by doing something as simple as chewing gum! Not any gum, mind you, but gum sweetened with xylitol. At least two major studies have shown that chewing xylitol-sweetened gum can reduce chronic ear infections. In preschoolers, ear infections were reduced by a whopping 50 percent!
Apparently, xylitol prevents bacteria from attaching to the back of the mouth from where they can later migrate to the ear and cause infection. Xylitol also inhibits the growth of bacteria, particularly Pneumococci, which is the species often responsible for acute otitis media. In the studies, about 10 grams of xylitol a day did the job, equivalent to about three sticks of gum. Perhaps worth a try for children who spend the winter coming down with ear infections and practically live on antibiotics. And there is a bonus. Chewing xylitol-sweetened gum is really cool. The compound has a large negative heat of solution, which means that it produces a refreshing cool taste in the mouth. Any potential harm with xylitol? In rare cases it can cause loose bowel movements. That’s it. So how about some xylitol-sweetened gum? And don’t let the fact that it may have a shellac coating bug you.