How much milk should my child drink?
It's one of the most common questions pediatricians get asked when parents introduce cow's milk into a 1-year-old's diet. And now researchers from Canada think they have come up with a definitive answer: two cups per day.
"We started to research the question because professional recommendations around milk intake were unclear and doctors and parents were seeking answers," says Dr. Jonathon Maguire, a pediatrician at St. Michael's Hospital in Toronto, Canada, and the study's lead author.
Currently about 70 percent of children drink cow's milk on a daily basis. Fortified milk is considered one of the healthiest foods around—it has protein, calcium, and vitamin D, which is key for healthy bone growth and disease prevention.
But too much milk can be a problem. As Claire McCarthy, MD, writes in her MD Mama blog, "Fortified milk may be high in calcium and vitamin D, but it's low in iron. Not only is it low in iron, but drinking a lot of it interferes with the body's absorption of iron and can even cause small amounts of bleeding in the intestine, further lowering the amount of iron in the body."
Drinking too much milk—like eating too much of anything—can also make little tummies less likely to try other foods, like meats and leafy green vegetables, which are often already a challenge to get some kids to try.
So, to find out the ideal amount of milk that provides optimal amounts of calcium and vitamin D, but doesn't put iron stores at risk, Maguire recruited approximately 1,300 healthy children, aged 2 to 5 years old, to find out how much milk they were drinking. Parents were asked to fill out an extensive questionnaire about their children's milk intake and other factors that could affect iron and vitamin D stores, such as time spent outside. A blood sample was obtained from each child to determine body stores of iron and vitamin D.
It instantly became clear to researchers that children who regularly drank more than two cups of cow's milk had higher vitamin D stores, but lower iron stores.
"We saw that two cups of cow's milk per day was enough to maintain adequate vitamin D levels for most children, while also maintaining iron stores. With additional cow's milk, there was a further reduction in iron stores without greater benefit from vitamin D," explains Maguire. Beyond the milk issue, children's blood tests also uncovered some important information about which child would benefit from a vitamin D supplement. According to researchers, children with darker skin pigmentation may not have enough vitamin D stores during the winter months. However, instead of consuming more fortified milk to increase these levels, but possibly deplete iron stores, these children may benefit from a wintertime vitamin D supplement.
And what about kids who can't drink milk, whether it's due to a food allergy or family diet preference? Remember, cow's milk isn't absolutely necessary for a healthy diet—there are other ways to get the nutrition it offers. Fortified soy or almond milk may be a suitable substitute, as well as looking for non-dairy sources for calcium, vitamin D, and protein.