Your grandmother said it. Every cafeteria poster said it. Drink your milk and you'll grow up big and strong.
Was she right? Scientists in Copenhagen decided to check. What they found is more interesting than the poster.
The study
In 2004, a team at the Royal Veterinary and Agricultural University in Denmark took 90 healthy two-and-a-half-year-olds and did something unusually careful. For seven days, parents wrote down everything each child ate and drank. Then the researchers measured two things: how tall each child was, and how much of a hormone called IGF-1 was circulating in their blood.
IGF-1 stands for insulin-like growth factor 1. Think of it as the messenger. Growth hormone gives the order; IGF-1 carries it to the growth plates at the ends of a kid's bones, where new bone actually gets built. More IGF-1, more building.
Now for the result. The children who drank more milk were taller. They also had more IGF-1. And the numbers were not subtle: going from 200 mL of milk a day to 600 mL, about one cup to two and a half, went with a 30% increase in IGF-1.
Here's the part that surprised even the scientists
They didn't just look at milk. They sorted all the protein the kids ate into piles: animal protein, vegetable protein, meat, and milk.
Vegetable protein? No association with height. Meat? None either. Milk, specifically, was the one that tracked with both IGF-1 and height. Something in milk, beyond just "protein," was doing the work.
That is a real finding, not a poster.
One study is a clue. Twelve studies is evidence.
A single study of 90 toddlers tells you something is going on. It can't tell you milk caused the height. Maybe taller toddlers just happen to be thirstier.
So in 2012, a researcher named Hans de Beer did the harder thing. He gathered every controlled trial he could find where kids were actually given extra dairy and then measured against kids who weren't. Twelve trials, from Europe, the USA, China, Vietnam, Kenya, Indonesia, and India, some going back to 1926.
The pooled result: about 0.4 cm of extra growth per year for every 245 mL of milk a day. That's one cup. Over a childhood, that adds up to real inches. The effect was bigger in teenagers and in kids who were shorter than average for their age, which is exactly what you'd expect if nutrition was the limiting factor.
He rated the evidence "moderate quality." Some of the older trials weren't perfectly randomized. That's honest, and it's still a lot more than a poster.
So does milk make kids taller?
Here is the careful answer, and the careful answer is the interesting one.
Height is mostly genetic. Roughly 80% of the difference between one kid and the next is inherited. You can't feed a kid past their genes.
But genes set a range, not a number. Nutrition decides where in that range a kid ends up. Look at the Netherlands: Dutch men went from among the shortest in Europe to the tallest in the world in about 150 years. Their genes didn't change in 150 years. Their diet did, and it was heavy on dairy.
That's what the Danish study and the twelve trials are really measuring. Not "milk makes tall kids." Milk, and the protein, calcium, and growth signals in it, help a kid reach the top of their own range instead of the middle.
What's in milk that matters
Try this: pour a glass of milk and look at it as a delivery system.
- Protein, about 8 grams a cup. The raw material for every new cell, and the thing the body converts into that IGF-1 signal.
- Calcium, about 300 mg a cup. Bone is a calcium building. No calcium, no building.
- Vitamin D, in fortified milk. The key that lets calcium into bone at all.
- Milk-specific compounds that the Danish team suspects nudge IGF-1 up more than the same protein from meat.
Now notice something about that list. Nothing on it says "must come from a cow." The protein and the calcium and the vitamin D are the nutrients. Milk is one very good package for them.
What this means if your kid won't drink milk
A lot of kids won't. Preference, allergy, lactose, or just the age-six declaration that milk is "gross." When milk leaves the diet, the protein and calcium numbers usually drop together, and quietly.
We built Wonderade with this exact study in mind. Each box carries 8 grams of protein, 300 mg of calcium (25% of a kid's daily value), and vitamin D, in a juice a kid actually asks for. The protein isn't milk protein; the box is dairy-free. It delivers the nutrients the research points to, in a format that doesn't come home full.
We want to be plain about one thing: nobody has run the Danish study on Wonderade. It's a juice with the growth nutrients milk is famous for, not a milk substitute with a clinical trial behind it. We think that's the right way to say it, and we'd rather say it that way than the poster way.
You can see the full nutrition panel next to a typical juice box here.
FAQ
Does drinking milk make you taller? Milk is consistently associated with taller stature in children, and controlled trials pooled in a 2012 meta-analysis found about 0.4 cm of extra growth per year per cup of milk a day. Genetics still set the range; milk helps kids reach the top of theirs.
What did the Danish milk study find? Hoppe and colleagues (American Journal of Clinical Nutrition, 2004) measured 90 healthy 2.5-year-olds and found milk intake was associated with both height and IGF-1, the growth hormone messenger. Raising milk from 200 to 600 mL a day corresponded to 30% more IGF-1. Meat and vegetable protein showed no such link.
How much milk should a child drink to grow? The trials that showed a growth effect added roughly one cup (245 mL) a day. The AAP suggests about 2 cups of milk a day for ages 2 to 3 and 2.5 cups for ages 4 to 8, as a general guide. More isn't better past that; it crowds out food.
What if my child is allergic to milk or won't drink it? Focus on the nutrients milk provides: protein (around 8 g per serving), calcium (around 300 mg), and vitamin D. Fortified alternatives, yogurt, cheese if tolerated, and drinks formulated with those nutrients can cover the gap. Talk to your pediatrician about growth if you're concerned.
Can Wonderade help my child grow taller? Wonderade provides 8 g of protein, 300 mg of calcium, and vitamin D per box, the nutrients the growth research points to. It has not been studied for height, and no drink changes a child's genetic range. It supports normal growth as part of a healthy diet.
Want to see what 8 grams of protein and 300 mg of calcium taste like in a juice box? We're sending free samples to founding families before launch. Claim your free sample. No commitment, just first access.