Drinking two cups of milk a day is enough to balance vitamin D and iron needs in most young children .
Two cups of cow’s milk per day may be enough for most kids to have the recommended amount of vitamin D in their blood while maintaining a healthy iron level, suggests a new study.
The American Academy of Pediatrics (AAP) recommends children between two and eight years old drink two cups of milk per day, but in another guideline, the organisation also says children need supplemental vitamin D if they drink less than four cups per day.
That’s not a blanket suggestion for all children, however. Dr Maguire Canadian Pediatric and his colleagues say darker skinned children may need three to four cups of milk per day during the winter, when their bodies produce less vitamin D naturally from sun exposure.
“Vitamin D deficiency in children has been linked to bone health issues and iron deficiency has been linked to anemia and delays in cognitive development,” Dr. Maguire said. “Being able to answer parent’s questions about healthy cow’s milk intake is important to avoiding these potentially serious complications of low vitamin D and iron stores.”
“For each additional cup of milk, it reduces the iron stores by a little bit,” said study author Dr. Jonathon Maguire of St. Michael’s Hospital and the Hospital for Sick Children in Toronto.”But in children who are at risk for iron deficiency for example, that little bit actually is very important.”
In children with very low iron stores, the brain doesn’t develop in the same way as in their peers who weren’t iron deficient. In the long term, that can lead to difficulties with school performance and behaviour, Maguire said.
For the study, researchers analyzed blood samples from 1,311 healthy children aged two to five during routine visits to the doctor. Parents were asked how many 250-mL cups of cow’s milk their child drinks a day or if the child currently uses a bottle. The average daily milk intake in the study was 460 mL.
Each cup of cow’s milk increased vitamin D by 6.5 per cent on average and decreased iron stores by 3.6 per cent on average.
Gender, season, vitamin D supplementation, skin pigmentation and drinking from a bottle were all factors in the trade-off, the researchers said.
Dr. Maguire concluded:
“Vitamin D deficiency in children has been linked to bone health issues and iron deficiency has been linked to anemia and delays in cognitive development. Being able to answer parent’s questions about healthy cow’s milk intake is important to avoiding these potentially serious complications of low vitamin D and iron stores.”
Dr. Maguire and his team looked at how cow’s milk affected body stores of iron and vitamin D – two of the most important nutrients in milk – in more than 1,300 children aged two to five years.
They found that children who drank more 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,” Dr. Maguire said.
The researchers recruited healthy children during routine doctor’s appointments between 2008 and 2010. Parents were asked to fill out an extensive questionnaire about their children’s milk drinking habits and other factors that could affect iron and Vitamin D stores. A blood sample was obtained from each child to determine body stores of iron and Vitamin D.