When you think about foods that cause cavities, you probably think of things like candy, soda, cookies – the sweet stuff. Truly, though, the harmful bacteria in your mouth love all fermentable carbs – not just sugars but starches, as well. Think pasta, bread, chips, fries – foods made from wheat, corn, potatoes, and such. Saliva quickly breaks down these foods into sugars, feeding those pathogens.
Those bacteria, in turn, generate acids that eat through tooth enamel, leaving the teeth vulnerable to decay.
Most of us don’t really think about the starches. Yet they were the focus of a recent study in Microorganisms that shed some new light on their role in the decay process, particularly in people with certain genetic variations.
The key player here is a gene called AMY1, which codes for salivary amylase. This is an enzyme in your saliva that starts the process of breaking down starches into sugars. Different people have different numbers of copies of this gene – anywhere from two to 20. The more copies you have, the more amylase enzymes your body produces and the more efficiently you break down starches.
For their study, researchers collected saliva samples from 31 people with varying numbers of AMY1 copies to see how their oral bacteria responded to starches.
They found that when starch was present, bacterial diversity in the mouth decreased. For people with lots of AMY1 copies, some potentially harmful bacteria decreased, while others associated with decay, such as Streptococcus, appeared to increase. This suggests that our genetic makeup might influence how our mouth’s ecosystem responds to starches.
Interestingly, people from populations with long histories of agriculture and starch consumption tend to have more copies of AMY1. While this was likely an evolutionary advantage way back – allowing our ancestors to get more calories from starchy foods during periods of scarcity – it now clearly has some drawbacks in our culture of food abundance.
It’s important to note that while these findings don’t deliver a definitive verdict, they do offer a glimpse of the complex relationship among our genes, what we eat, and our oral microbiome. And while we can’t change our genetic makeup, we can change our behavior in light of what we know about the impact of sugars and starches on oral health. (Note: Decay is only one problem. These foods also fuel gum disease, not to mention an array of systemic health issues.)
One key behavior, of course, is practicing good hygiene, especially after eating sugars and starches. At minimum, that means brushing twice daily and flossing once daily. If you brush after meals, make sure you wait at least a half hour. This gives your saliva an opportunity to neutralize the acids so you don’t wind up brushing them into your teeth.
The other key is to eat fewer sugars and refined starches. Going with whole grains- properly prepared – is one option, as they’re digested more slowly and may reduce the rapid production of sugar in your mouth. Or you can displace them with vegetables, including those that become stand-ins for common starchy foods: cauliflower rice instead of white rice; zucchini noodles instead of pasta; lettuce wraps instead of bread; sweet potatoes instead of white potatoes.
These aren’t dramatic dietary shifts, just simple changes that support oral and whole body health alike – regardless of your particular genetic makeup.
