Science debunks the biggest myth about coffee and growth

There are many moments in childhood that signal the inevitable arrival of adult life. Sometimes it's emergent body odor. Other times, it’s realizing your parents cause skin-crawling embarrassment.

But perhaps none signal the transition from the carefree life of a child to the schedule-bound life of an adult quite like a newfound appreciation of, and addiction to, coffee. A drink that once appeared murky brown and bitter transforms into toffee-colored nectar of the Gods.

How young is too young to make this transition to a coffee lover? A parent or grandparent likely warned you against the caffeinated beverage for fear of it stunting your growth.

However, this is actually a myth — more a product of clever advertising than scientific reality.

The origin of the myth: bad advertising

It’s no surprise that advertising has a powerful effect on the human psyche, and anti-coffee campaigns are no different.

It all started with an ad campaign run by the Post cereal company (who today makes cereal ranging from Grape-Nuts to Oreo O’s) to promote a coffee substitute dubbed “Postum.”

“You can't ‘undo’ bone growth once it's complete.”

Made from grain and molasses instead of coffee beans, Postum was designed as a hot drink that could be served to children as an alternative to coffee. A modern reviewer said it tastes of “liquid burned toast with a hint of molasses flavor.”

The drink itself was developed in 1895 but the campaign that first introduced the notion that coffee could stunt growth ran in the Boston Daily Globe in 1901, reports Wirecutter.

The same ad also warned coffee “prepares [children] for dyspepsia and nervous wrecks.” It was not uncommon for parents — especially mothers — to fear children having “coffee delirium.”

While Postum’s ads did draw on pseudoscience to support their anti-coffee claims — such as claiming investigations showed coffee reduced children’s weight — these claims weren’t substantiated.

Postum has pulled back on this messaging today and is now primarily enjoyed as a nostalgic beverage or as a coffee alternative for diets that preclude caffeine (it’s particularly popular among Mormons).

But the damage to coffee’s image had already been done.

Does coffee stunt a person’s growth?

Since Postum’s smear campaigns against coffee, scientists have worked to investigate whether this claim could possibly be true.

Short answer? It does not.

The closest studies have come to connecting stunted growth to coffee consumption were a series of studies from the 1990s and early 2000s which drew a connection between an increase in caffeine consumption and a decrease in calcium absorption in the body. Such a calcium absorption problem could theoretically lead to osteoporosis — a condition associated with a loss of height.

However, the calcium difference found in these studies is essentially negligible (as more recent studies have shown) and may be easily accounted for with a little extra milk in your cup of joe.

Another string that unravels this myth is who exactly it's aimed at. While Postum’s was marketed to children, the coffee myth now appears to be disseminated unilaterally.

While adolescents under 18 are increasingly drinking more coffee (the National Coffee Association estimated in 2017 that 37 percent of 13 to 18-year-olds consume coffee) the majority of coffee drinkers are still adults. Most people have reached their full height by this time. As explained in a Harvard Health article: “You can't ‘undo’ bone growth once it's complete.”

At what age can children drink coffee?

Height concerns aside, the American Academy of Pediatrics does still recommend that children under the age of 12 should not consume more than 100 mg of caffeine a day — whether that be from chocolate to coffee and energy drinks.

For comparison, adults can safely consume up to 400 mg per day — or about four to five cups of coffee.

“Too much caffeine can cause issues such as increased anxiety, increased heart rate and blood pressure, acid reflux, and sleep disturbance,” explains a Johns Hopkins Medicine blog. “Too much caffeine is dangerous for kids, and in very high doses, can be toxic.”

The benefits of a cup of joe

When it comes to full-grown adults enjoying a cup of coffee (... or several) throughout the day, science has shown again and again that this daily ritual may actually have more benefits than drawbacks, including helping reduce the risk of:

• Type 2 diabetes
• Stroke
• Parkinson's disease
• Alzheimer's disease
• Certain cancers
• Gout

While scientists are far from claiming that coffee will beyond doubt protect you from these ailments, it’s a comforting thought to ruminate on during your morning pour-over.

CHECK, PLEASE is an Inverse series that uses biology, chemistry, and physics to debunk the biggest food myths and assumptions.

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