Experts Say Eating Too Much of This Food Type Can Destroy Your Teeth — And No, It’s Not Sugar

Saliva, this clear, colorless liquid lubricating the innards of the mouth, is a potent, magical biofluid that possesses within it startling secrets of life, including the ghosts of ancient ancestors and, of course, an individual’s DNA. The squishy saliva comes in contact with the taste buds in the mouth to give rise to one of the most fascinating sensations of human experience: taste. A recent research published in Microorganisms revealed that a gene called “AMY1” encoded in the DNA in human saliva could be responsible for causing cavities and tooth decay, probably more than all those chocolates and sugar. This gene is found in starchy foods.

Previously, these sugary desserts and syrupy toffees were regarded as the culprit behind tooth decay. However, this research challenged the notion by suggesting that a person’s saliva itself could be the guilty party instead. Researchers from Cornell University in New York found that a person’s genetic makeup, as revealed by their saliva, could hide the recipe for persistent tooth and gum problems. They discovered that a gene called AMY1, or salivary amylase, responsible for the digestion of starches and carbohydrates in the mouth, alters the complex composition of bacteria that play a role in oral health.

“Most people have been warned that if you eat a bunch of sugar, make sure you brush your teeth. The takeaway finding here is that depending on your AMY1 copy number, you may want to be just as vigilant about brushing your teeth after eating those digestible starches,” Angela Poole, the study’s co-author, said in a press release. As part of this research, Poole and her colleagues, including Dorothy Superdock, collected saliva samples from 31 individuals with copies of the AMY1 gene in their DNA.

They asked individuals to “refrain from brushing their teeth for at least six hours and eating or drinking for at least 30 minutes before sample collection,” according to the paper. Each individual donated about 5 to 10 milliliters of unstimulated saliva through passive drooling. These samples were stored in sterile conical tubes and preserved in glycerol. In the next step, they added starch to the cultured samples or biofilms to examine how they changed the bacterial makeup of the saliva.

Analysis revealed that two bacteria, “Atopobium” and “Veillonella,” decreased in the saliva after the addition of starch, while a third bacterium called “Streptococcus” increased. All three of these bacteria, Poole said, are related to tooth decay and gum disease. “Some increased and some decreased, so it’s not so straightforward as saying, ‘The whole thing is good or bad.’ It’s an interaction, but it looks like the AMY1 copy number, as well as which species are present in people’s mouths when they eat starch, is affecting the risk for developing these diseases,” Poole explained.

Starch, often found in foods like bread, pasta, potatoes, bakery items, crackers, chips, lentils, corn, and rice, is the primary source from which the body derives its fuel supply. Not only do starches aid in digestion, but they also cushion the joints with membranes of essential fat. And although bodies with higher copies of the AMY1 gene can break down starchy foods more easily, the gene itself carries the possibility of spoiling the bacterial protection of the mouth. “If someone has a high copy number, they break down starch efficiently, and bacteria that like those sugars are going to grow more in that person’s mouth,” explained Poole. This experiment could unlock new doors for personalized dental care, tailored to suit the specific individual based on the genes swimming in their saliva.