Caffeine

Caffeine stunts your growth

Aaron loves coffee. Loves it. In fact, he’s somewhat of a coffee nut and has been known to roast his own beans. But when he was young, his parents—like many of yours—told him that he couldn’t drink coffee because it would stunt his growth. That was the line in Rachel’s family too, but since they were all tall Dutch people who had consumed massive amounts of coffee from young ages, the threat didn’t hold much credence.

It’s not totally clear where this myth comes from. Ironically, some believe it stems from the same literature that allegedly linked carbonation to brittle bones. If you remember, those studies found that it wasn’t the bubbles in the drink, but perhaps the caffeine that led to problems in calcium in bones. Some people may have extrapolated this to mean that caffeine reduces the calcium available to your bones, which leads to bone problems, which leads to stunted growth. Case closed!

Or not. When we follow coffee or caffeine drinkers over time in good prospective studies, we see that this really isn’t the case. Growing bones does require your body to use calcium. If caffeine prevents your body from absorbing calcium, then it seems feasible that caffeine would stunt bone growth. Science does not bear this out. In studies, caffeine did slightly limit how well the gut absorbed calcium. However, the studies also showed that the body compensates easily for this change in calcium absorption, by decreasing how much calcium it gets rid of in your pee over a twenty-four-hour period. The overall difference in calcium absorption is quite small. In fact, the study finding that calcium was not absorbed as well when you drink caffeine stated that whatever negative effects the caffeine had on calcium absorption could be overcome by drinking an extra one or two tablespoons of milk.

Some posit that people who drink caffeine may be taking in less dairy or drinking less milk. That’s possible, but it’s a far cry from claiming that coffee stunts your growth.

There’s more. Another study enrolled eighty-one girls between ages twelve to eighteen to see how caffeine affected their total body bone mineral gain and hip bone density over a six-year period. One group consumed less than 25 mg of caffeine per day, one consumed 25 to 50 mg of caffeine per day, and one consumed greater than 50 mg of caffeine per day. The researchers found that there were no significant differences among the three groups with respect to the bone health. Caffeine intake at various levels did not affect bone health or growth.

Caffeine is a commonly used drug in the neonatal intensive care unit, where premature babies are cared for. We use it to stimulate them when their brains are immature; it helps them to breathe on their own. If there was any real evidence that caffeine would stunt their growth, we wouldn’t be using it there.

There are, of course, plenty of reasons not to give kids caffeine. Unlike sugar, caffeine can affect their behavior and even their sleep. But it won’t stunt their growth.