Transcript: Do Raisins Cause Cavities?
Raisins have a long-standing reputation as a food that promotes cavities, based on decades-old studies on rats that ranked raisins up there with cupcakes as among the most cavity-promoting foods. And to this day, you’ll see dental authorities advise against eating dried fruit, like raisins. But more recent evidence—studies done on actual people—casts some doubt on the role of raisins with regard to tooth decay.
The formation of cavities depends on three factors: acid, adherence—the stickiness of food to teeth, and the bacteria that make up the dental plaque. If you have a child swish some sugar water in their mouth, within five minutes, the pH of the plaque on their teeth plummets, as the bacteria convert the sugar to acid. And raisin bran was practically just as bad. Bran flakes alone, without the raisins, weren’t as bad, but is that because the raisins in raisin bran are crusted with sugar, or because of the raisins themselves? Well, raisins didn’t lead to much acid at all, and the big surprise was that if you combined the non-sugar coated raisin with the bran flakes to create a kind of experimental raisin bran, the raisins seemed to prevent some of the acid the bran flakes were causing.
So, although raisins are like 70% pure sugar, they caused less acid to be produced; so, although they’re sweet, they don’t appear to adhere to our teeth. But don’t raisins stick to your teeth? 21 foods were put to the test, and there was actually no relationship between food retention and how sticky the foods appeared to be. Bits of cookies, crackers, and potato chips actually stuck to the teeth the longest, whereas things you’d think would stick, like caramel and raisins, disappeared within minutes, though fresh fruit like apples and bananas disappeared from the mouth almost immediately.
Phytonutrients in grapes appear to actually prevent the adherence of bacteria and prevent plaque formation, so much so that grape pomace, the by-product of wine making, is being investigated as a cavity-preventing food additive. Or, you could just drink the wine. Dealcoholized wine inhibits the growth of the primary cavity-causing bacteria, though raisins would probably be a more appropriate snack for kids.
There’s a new test out to measure the cavity-causing activity of plaque bacteria. So, a pilot study was performed to see if the risk for cavities increases, decreases, or remains the same after eating raisins. They took 156 folks, swabbed their teeth, waited for the readings to get up over 1,500, which indicates high cavity-causing activity, and had half eat a little box of raisins and the other half eat nothing. In that eat-nothing control group, they started out up at around 6,100 and 15 minutes later were still up at 6,100. The raisin group started up around 5,950, but after raisin consumption, their cavity risk score dropped down to 3,350. Although that’s a big reduction, note the score was still left higher than the 1,500 cutoff, indicating they were still at risk, but the risk went down after raisins, not up. So. while traditionally, raisins have been thought to promote tooth decay, current research suggests that raisins may not contribute to cavities after all, or at least not any more than other foods.
To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video. This is just an approximation of the audio contributed by Katie Schloer.
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