More weight, fewer cavities? (Chang W. Lee/The New York Times)Overweight children have healthier teeth than normal weight kids, a new study shows.
The surprising finding, published this month in the journal Community Dentistry and Oral Epidemiology, comes from researchers at the Eastman Dental Center at the University of Rochester Medical Center. They analyzed data from nearly 18,000 children who participated in two separate major surveys that were part of the large and ongoing National Health and Nutrition Examination Survey.
Among youngsters ages 2 to 5, there were no differences in rates of tooth decay. However, among children ages 6 to 18, those who were overweight or at risk for becoming overweight had fewer cavities than kids of normal weight. A child was considered overweight if he or she was in the 95th percentile or higher, based on age and sex. Children in the 85th percentile or above were defined as at risk for becoming overweight.
The findings don’t mean being overweight protects teeth, but they do raise questions about the differences in foods eaten by overweight children compared to their normal weight peers. It also debunks the stereotype of the overweight child who binges on cavity-causing candy and sugary foods. One theory is that overweight children may actually be eating fewer cavity-causing sweets than normal weight kids and instead overeating fatty foods.
“We expected to find more oral disease in overweight children of all ages, given the similar causal factors that are generally associated with obesity and caries,” said Eastman Dental Center’s Dr. Dorota Kopycka-Kedzierawski, the lead author, in a news release. “Our findings raise more questions than answers. Research to analyze both diet and lifestyle is needed to better understand the results.”
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It isn’t difficult to explain: Overweight children consume more food, and, therefore, chew more. Chewing enables the natural cleaning of teeth and periodontal pockets, as well as stimulates saliva secretion — three factors essential for cavity-prevention. Also, their more varied and abundant diet provides more nutrients, essential for bone formation and prevention of periodontal disease. On top, overweight kids are more likely to have better teeth to begin with because that’s what is required to become overweight in the first place.
Konstantin Monastyrsky, author of Fiber Menace
— Konstantin Monastyrskyhttp://www.FiberMenace.com
So maybe this is why my teeth are so horrible!
— EmilyPerhaps it could also have something to do with metabolism in general. With a fast metabolism, things tend to go right through me. I end up keeping fewer calories in me. But could I also be absorbing fewer essential nutrients? Perhaps my body doesn’t hold onto calcium and other things needed for healthy teeth as someone who has a slower metabolism.
Maybe kids who have gotten cavities have one more deterrent to eating unhealthy food: the memory of getting fillings. If I’ve been told that candy is bad for my teeth and my weight, and the dentist says “your teeth are great,” maybe I’ll think I’m not overdoing it.
— JesseInteresting. I definitely would have expected otherwise. While overweight kids may overeat on fatty foods, is there any reason they would eat fewer cavity causing sweets?
The New Cook
From TPP — Foods displace other foods. If we load up on hamburgers and fries and milkshakes, it makes sense that we would be less likely to eat a pack of Skittles. I also wonder — and this is just a question on my part — if overweight kids might eat faster. I know a lot of little kids tend to suck on their fruit flavored skittles and dentists fret about this because it’s bad for teeth. I wonder if scarfing down your candy gives your teeth less exposure to it. I’m sure a dentist out there will know more about this issue than I do so please, let’s hear from you!
— AndyI wonder if the study took into account the possiblity of the overweight kids’ lying about their diets, omitting junk food and sweets.
From TPP — The study didn’t look at diet at all. It looked at cavities and weight. The overweight kids had fewer cavities. The theories about the kids’ diets are just speculation, although another study could go back and look at diet, weight and cavities.
— LeahWhy why why wouldn’t they control for children’s height? The heavier kids may just be the taller ones with MORE ROBUST BONE GROWTH! Talk about confounder for dental health!
— LizJust an unscientific guess, but I don’t think children get obese on candy and other high-sugar confections (which are relatively small and take time to eat) so much as they do on massive-fat “meals” they can scarf.
— William McCloskeyThis would support my hypothesis that the problem of obese kids isn’t about over-eating but about lack of exercise. I would be interested to see a study also comparing caries rates in kids of different academic achievement too. My hypothesis is that smart kids spend more time at the books and less time playing mindless sport - and they probably get fatter because of it. They don’t need fewer calories just because they’re growing in front of a computer or book and not on the football field, but they’re the equivalent of the sedentary professional who is often fatter than the gym-babe secretary who only just finished high school.
Once we see that there are a plethora of rational or even desirable choices that have obesity-risk effects we might start a) treating fat people better and b) start giving treatments that take into account their rationally chosen lifestyles and not what our ancestors would have done on the African plains (ie run a lot to get away from predators). It is not always BAD to defy evolution and reward people who like to sit at desks and use their brains rather than their muscles.
So far obesity research has always focused on getting people to spend more time doing X (ie exercise) which takes away time from their family and work. That time matters a lot more to those who have the brains to get into sedentary high-paying jobs where they don’t have the time. The other thing we do is say eat less - but below a certain point you impair your ability to think clearly, and suffer gyrating sugar levels if you cut back too far.
For some people that would be the cutback needed to maintain or lose weight given their long-hour sedentary jobs. If we took the moral judgment out of treating obesity and started trying to develop treatments that are compatible with sedentary lifestyles (ie not defining those as BAD), then I think we will be on the right track.
Re kids it actually makes a lot of sense. The other thing is that caries is prevented by prompt brushing even if you do eat junk. Perhaps the overweight kids brush their teeth more BECAUSE they eat more? And brushing more often has this side effect that they have lower caries rates.
— JillyflowerOne wonders about the warnings that sugary soft drinks contribute to childhood obesity. Wouldn’t drinking all that pop (as we Midwesterners call it) also result in more cavities?
From TPP — Interesting point.
— Mark ForstnegerMy teeth went dramatically south in a period of two years during which I developed an uncontrollable Altoids habit. (I had to eat them in the car or I couldn’t drive properly. The space in front of the passenger seat filled up with Altoids tins to the level of the seat. No lie. Okay, slight lie. But it was several layers of tins.) I developed 16 cavities and gained 16 lbs. during this interesting period of my life. When I withdrew (in agony) from Altoids, the cavities stopped and a dozen pounds dropped effortlessly off my frame. No offense to Altoids, the King Of Mints. Enjoyed in moderation, they are a fine, fine comestible. Some of us, though, cannot freshen responsibly and must simply suffer through life with stale, clean teeth.
— Mint MavenThere are genetics to bone metabolism. Often people who are genetically thin are prone to osteoporosis and fracture.
Perhaps dental metabolism and the production of dental enamel is similar.
— rini10I think Emily may be on to something. I was a wicked skinny kid and I had a whole set of teeth come in with bad enamel. Fewer dental problems as I got older and reached a more average weight.
— anneDid the study not take height into account? The article mentions only age and sex. Children are given percentiles in both height and weight. A taller and heavier child, with a 95th percentile in both categories for example, might not be overweight at all but just large for their age. If this is the case, one of the reasons for their faster growth could be the high quality of their food and their healthy habits.
— CR#10, there is a brand of mints that is actually good for your teeth. It’s made with Xylitol. I think in America it’s called XyliFresh. But, be warned, although it won’t ruin your teeth, it is just as fattening as mints sweetened with normal sugar.
— SusannaMy son has been over the 95th percentile for weight most of his life. Does this mean he’s overweight? He looks like a rail to me. He’s also over the 95th percentile for hieght.
— CDTKids are growing all the time. It is not uncommon for kids to become “at risk of underweight” while they are in a height growth spurt, then move to “normal” and “at risk of overweight” in preparation for the next growth spurt.
Toss in that in kids the difference between “normal” and “at risk” can be, oh, a pound, and I can’t help but wonder how useful any of this data is.
If a kid stays in the 90 percentile for weight every month for years, that’s one thing. If the kid is seesawing around between growth spurts, that’s just “noise” for the purposes of this sort of study.
— JenKI think Tara may have mis-typed - the definition for overweight/obese for children (according to CDC) is based on BMI for age, not weight for age. CDC definition is >85th percentile BMI for age is “at risk for overweight”, >95th percentile for age is “overweight”. BMI takes into account both height and weight: weight in kg/(height in m)^2. So, to answer #6 and #13 above, they did likely take height into account.
— GinnyFrom TPP — You’re right. It’s BMI for age…which by definition takes into account height and weight for age. i’ll fix on the post.
Re: Jillyflower
While you make a point about the amount of time ’smarter’ people may spend at a desk job, being intelligent does not mean that you view exercise as ‘mindless’ or useless. Exercise can be a way to help you function better in activities that require intense thinking; getting out excess energy gets you ready to work when you sit down at your desk. And at a recommended level of caloric intake (even for dieters) that contains healthy fats, protein, and complex carbohydrates, there are no productivity reducing ’sugar crashes’. I feel that there are reasons that many intelligent people consider when making choices on their diet and exercise programs to stay at a healthy weight; medical problems, quality of time with kids (a small 45 or so minute moderate-intense workout 5 days a week might only take a little less than an hour, but still provide much more enjoyment for the rest of the time you spend with your kids), and just feeling better for the rest of their day.
— Exercise lover and (hopefully) not a bimboThis study was done over ten years ago and the results were the same. In the past study it was stated that fat kids ate more sweets, but the germs that cause cavities fed more on the the sugar than the teeth.
— DJust to remind you, Fat Albert had pretty shiny teeth too. And he laughed a lot. And had lots of friends.
I think the guy with the hat pulled down over his eyes had a toothache once and he was pretty skinny.
And this proves that you can learn everything you need to know from comics. Sometimes decades in advance.
— marleyinocWhen I see comments like:
“Often people who are genetically thin are prone to osteoporosis and fracture.”
“I was a wicked skinny kid and I had a whole set of teeth come in with bad enamel.”
I think undiagnosed celiac disease. Especially on the second, as bad enamel is a well documented symptom of undiagnosed celiac.
— Don WissIt’s very simple. Overweight children are getting enough to eat. They are getting the vitamins, minerals, protein and calcium needed to have healthy teeth and gums. The fact is, overweight people in general are much healthier than thin people. Thats because people considered overweight are getting enough to eat. And that includes children.
Best,
Rebecca
— RebeccaTwo thoughts:
Teeth are formed during pregnancy. Could the mother’s prenatal diet affect the rate of dental caries?
How was the weight status determined? Growth charts or BMI? I agree that height should be included.
And all kids have other risk factors that could be used in correlational studies about dental caries: family history, blood pressure, cholesterol, but especially diet/exercise. I’d like to see more research on this interesting subject.
Ellie @ http://www.feedingthekids.com
— Ellie TaylorThere are a fair number of overweight kids out there who simply drew a “fat” hand of genetic cards (take a look at their parents, their siblings, their aunts and uncles and grandparents) and who eat considerably LESS than their thin schoolmates in a sadly doomed effort to try and compensate. Just like there are a fair number of super-thin kids out there who’ll go through six slices of pizza at a sitting like a tornado. There aren’t nearly enough data in this study to do more than the most speculative theorizing.
— LRQPerhaps the causation is the other way around. Maybe children with more cavities eat less because their teeth hurt (or they could be afraid of getting more cavities). Whenever I see reports of a correlation study, I try to imagine possible explanations of causation going both ways or explanations invlolving a third factor which would cause both effects. Many people have mentioned interesting possible explanations.
Also, did the study separate underweight children from those with “normal” weight? Underweight children might be malnourished, and you’d expect their teeth to be bad. Could they be pulling down the average for the normal weight kids? The way you reported it it looked like they looked at overweight kids vs. all other kids put together.
— Suzie