Two cups of milk a day advised for preschoolers

Toronto community study sorts out conflicting advice on a common question
By Terry Murray
Reposted from The medical post
QUEBEC CITY | How much cow’s milk should preschoolers drink?
This is a question parents often ask, and one that is of concern to pediatricians, knowing that not enough milk may result in low vitamin D serum levels, while too much may deplete iron stores.
In the absence of Canadian guidelines, Toronto researchers set out to determine the optimal daily volume of cow’s milk that would maximize both iron stores and vitamin D serum levels.
The answer from the study of more than 1,500 children ages one to five years, conducted by investigators with TARGet Kids! was 470 ml, or about two cups. TARGet Kids! (Toronto Area Research Group for Kids!) is a network of child health researchers and primary-care practitioners in the Greater Toronto Area.
Dr. Jonathon Maguire, a principal investigator with TARGet Kids! and a pediatrician at St. Michael’s Hospital, presented the data at a recent Canadian Paediatric Society (CPS) meeting.
The researchers recruited 1,579 preschoolers at their annual well-child visits to 15 community primary-care practices between December 2008 and October 2010. Their average age was 37 months, and just over half were boys.
Their milk intake and vitamin D supplementation were determined by questionnaire, and 25 hydroxyvitamin D (25 OH-vitamin D) and serum ferritin levels were measured by blood test.
The data were analyzed using the Scheffé simultaneous confidence interval, a statistical test for multiple comparisons, and multivariable linear regression modeling to adjust for the effects of age and vitamin D supplementation. The end result was that the optimal milk volume was 470 ml per day to maximize both 25 OH-vitamin D  and serum ferritin  regardless of age (between one and five years)  and vitamin D  supplementation.
“ ‘How much cow’s milk should my preschooler be drinking?’ is a very common question that gets asked of pediatricians and family doctors, and we really don’t have the answer to tell them. We don’t have an evidence base to support an answer,” Dr. Maguire said in an interview.
The CPS doesn’t have a cow’s milk intake guideline and the American Academy of Pediatrics (AAP) has conflicting recommendations. On the one hand, the AAP recommends that children who are ingesting less than 1,000 ml/day of vitamin D-fortified milk should receive supplemental vitamin D. But on the other, when considering iron status, the U.S. pediatric group has stated that cow’s milk intake should be limited to 500 ml (two cups).
“So this (the TARGet Kids! study) helps sort that out,” Dr. Maguire said. “If you take those two factors into account, the balancing point is about 500 ml. That’s probably the healthy amount of milk to be drinking.”