Dairy may be linked to children’s height
DEAR DOCTOR: My family tries to limit dairy products; it just doesn’t make sense to me that, marketing aside, humans should need milk from another species. But now I read that non-cow milk may be linked to shorter kids. Why would that be?
DEAR READER: The milk from breastfeeding is necessary for infant growth across all mammalian species, and humans are the only species of mammal that not only raise their young using the milk of another animal but also consume this milk in later life. So while it doesn’t make biological sense to drink cow milk, eat cheese or have creams and yogurt well beyond the time of breastfeeding, does it have a positive or negative effect on our bodies?
A 2017 article in the American Journal of Clinical Nutrition attempted to answer these questions. The authors asked 5,034 Canadian parents of children ages 2 to 6 about their children’s daily consumption of cow milk and non-cow milk products. The research showed that children who drank three cups of non-cow milk a day were about a half inch shorter than children who drank no non-cow milk. Similarly, children who drank three cups of cow milk a day were slightly taller than those who drank 3 cups of non-cow milk.
Here’s a possible explanation: The cow milk proteins, casein and whey, have been linked to an increase in size. Also, cow milk contains insulin-like growth factor-1 (IGF-1), which leads to the formation of more bone and cartilage and thus greater height.
Another possible explanation is that plant-based milks do not contain as much protein and fat as mammalian milk. Thus, children who drink these types of milks don’t get the calories or protein needed for greater growth.
Children who have food allergies are less likely to drink cow milk. Because food allergies have been associated with decreased height and weight, the allergies themselves may be a factor.
If you’re worried that avoiding dairy products will interfere with your child’s height, but you’re opposed to dairy products for personal or health reasons, I’d recommend you ensure that your child consumes plenty of protein in other ways.