How Do I Keep My Kid from Swallowing Fluoride?

My 2-year-old is swallowing fluoride toothpaste after brushing. Pediatricians and dentists insist on fluoride over non-fluoride toothpaste to prevent cavities. I’ve seen studies about the effects of fluoride in water on brain toxicity and lowering IQ, but not on toothpaste. Should I be worried about her brain development?
—Maria

We can dispense with the benefits first here. There are significant benefits to fluoride for preventing cavities. We have a lot of evidence on this. Non-fluoride toothpaste is better than nothing, but adding fluoride improves cavity prevention.

However, especially lately, we have been hearing many concerns about fluoride in water. Academic papers and meta-analyses have raised questions about a possible role of fluoride in lowering child IQ.

I’ve written more extensively about that literature here. Overall, the literature suggests that there are concerns about fluoride in water at high concentrations, such as those found in groundwater with naturally occurring fluoride in China and India. Studies that focus on lower levels of fluoride exposure do not show these same negative effects.

Fluoride exposure in toothpaste is potentially subject to similar concerns. A difference is that, for adults, you do not swallow the fluoride in toothpaste. So while you get a little exposure, it’s small relative to (for example) your water-based exposure. Kids do sometimes swallow toothpaste. However, if you use the appropriate amount of toothpaste, the exposure is still quite minimal.

A rice-grain-size amount of toothpaste (which should be all you need for a 2-year-old) has about 0.3 milligrams of fluoride in it. Even if they swallow all of it, this is only half of what a typical liter of water would have in it. In other words: toothpaste exposure, even for a chronic swallower, is a relatively small part of their overall fluoride intake. And, again, there’s really no strong evidence for fluoride being an issue.

I’d try to stop worrying about this. She will learn to spit out toothpaste eventually!