A second-grader drinks his milk during lunch. Can there be too much of a good thing when you are talking about little kids and cow’s milk? A new study suggests there can.

A second-grader drinks his milk during lunch. Can there be too much of a good thing when you are talking about little kids and cow’s milk? A new study suggests there can.

Hit the milky sweet spot

Can there be too much of a good thing when you are talking about little kids and cow’s milk? A new study suggests there can. The work, by scientists in Toronto, says that children between the ages of two and five should be drinking half a litre or approximately two eight-ounce cups of milk a day.

Can there be too much of a good thing when you are talking about little kids and cow’s milk? A new study suggests there can.

The work, by scientists in Toronto, says that children between the ages of two and five should be drinking half a litre or approximately two eight-ounce cups of milk a day.

Less than that and kids may not be getting enough vitamin D, the study suggests. But more than that, and the stores of iron in their blood — which are essential for a developing brain — may start to slip below acceptable levels.

The study was led by Dr. Jonathon Maguire, a pediatrician and researcher at St. Michael’s Hospital in Toronto. It is published in this week’s issue of the journal Pediatrics.

“Cow’s milk is a very important staple in our western diet for children. I don’t want to underestimate the importance of cow’s milk,” Maguire said in an interview about the study.

“Our question was really: Well, how much?”

It’s a query pediatricians face all the time, Maguire said. And they haven’t had a good answer to give because expert groups are divided on the issue.

Some organizations have argued that young children should consume a litre of milk a day to get the vitamin D they need to build strong bones and avoid rickets, a formerly common bone-softening condition. (Milk is fortified with vitamin D.)

But other groups have warned that children’s consumption of cow’s milk should be curtailed because some studies have shown that kids who drink a lot of milk can have low levels of iron in their blood.

Low iron can lead to anemia, where the body produces too few of the red blood cells that transport oxygen throughout the body.

“It looks like in children who have iron deficiency severe enough to cause them … to have anemia, those children have difficulties with their cognitive development. Over time they’re not quite as bright as other children,” Maguire said.

Iron deficiency in young children isn’t uncommon in Canada. While it’s just a guestimate — Maguire said recent studies haven’t been done — it is believed between 10 per cent and 20 per cent of young children in Canada may have low iron stores.

Given the confusing advice and the fact that milk consumption by preschoolers seems to involve a trade-off between vitamin D and iron, Maguire and some colleagues decided to try to find the sweet spot.

They enrolled 1,311 healthy Toronto children aged two to five in a study, evaluating samples of their blood for vitamin D and iron stores and gathering information from parents about the amount of milk the kids drank.

The researchers found that about 500 millilitres of milk a day for most children was the right amount to have adequate levels of vitamin D and iron.

There was an exception: during winter, children with dark skin didn’t hit the vitamin D target with 500 ml daily. The study suggests in winter children with dark skin may need a vitamin D supplement as well as the milk.

The researchers also saw this previously reported inverse relationship, where more milk consumed meant higher vitamin D levels but lower iron stores.

What’s behind the puzzling interplay? The director of the nutrition and metabolism research program at B.C. Children’s and Women’s Hospitals said little kids who drink a lot of milk often aren’t eating enough solid foods to get the needed amount of iron. (There is little iron in milk.)

Dr. Sheila Innis explained that some young children have a hard time making the transition from breast or bottle to solids. They may be drinking more milk because they still prefer to suck and swallow than to chew.

Innis said that parents of children like this should figure out what’s going on rather than cutting back on the milk.

“It’s a complicated problem when you’re dealing with, say, a three-year-old child who is … not a good eater. Stopping him drinking milk is not going to make that child a better eater,” she said from Vancouver.

In fact, Innis warned that trying to reduce milk intake in a child like this may provoke resistance and other problems. She urged parents in this situation to get help.

“Go see a good public health dietitian or nutritionist and get guidance on how to increase the variety and quantity of solid food in the diet. And then the milk intake will come down.”

A similar conundrum the study identified related to children over two who drank from a bottle. Analysis of their blood samples suggested they weren’t getting enough iron or vitamin D.

Maguire said this confirms something pediatricians see — many kids over two who still drink from a bottle are iron deficient.

“Given that it doesn’t seem to be much of a benefit from cow’s milk in the bottle for vitamin D and it looks like it decreases children’s iron source, it’s probably a good idea not to be using a bottle in children who are over two years of age,” he said.

Innis said bottle feeding over age two is also probably a sign of a child who is having a hard time making the transition to solid foods.

“Still drinking out of bottles over two goes hand in hand with not taking a good variety of solid foods. Not chewing well. Not liking textures. Still on sucking,” she said.

“It’s important when we talk about children still drinking from a bottle over two, what else are they doing?”

The study was funded by The Canadian Institutes of Health Research and the St. Michael’s Hospital Foundation.

Get local stories you won't find anywhere else right to your inbox.
Sign up here

Just Posted

A candlelight vigil will be held in Red Deer on Thursday to honour the 350-plus people killed in the Easter bombing attack in Sri Lanka. Contributed photo
Candlelight vigil planned for deaths linked to Olymel COVID-19 outbreak

A candlelight vigil is being planned for those who died due to… Continue reading

Red Deer Rebels forward Jaxsen Wiebe battles Calgary Hitmen forward Cael Zimmerman for a loose puck when the two teams squared off in February last season. (Photo by BYRON HACKETT/Advocate Staff)
Calgary Hitmen shutout Red Deer Rebels

Rebels name centre Jayden Grubbe team captain ahead of Friday’s game

Traffic will be delayed on 40th Avenue and 19th Street until the end of February. (Advocate file photo).
Traffic delays expected downtown this weekend

Red Deer drivers will be delayed in the downtown area of the… Continue reading

COVID
Red Deer down to 313 active cases of COVID-19

Alberta reports an additional 411 COVID-19 cases

Bryson, six, and Mara, eight, play with puppies from Dogs With Wings Saturday. (Photo by Sean McIntosh/Advocate staff)
WATCH: Dogs With Wings introduces Red Deer program

A program that trains puppies to be certified service, autism, facility and… Continue reading

Former Toronto Argonauts lineman Chris Schultz remembered as a gentle giant

Former Toronto Argonauts lineman Chris Schultz remembered as a gentle giant

Los Angeles Kings head coach Darryl Sutter, top, is shown on the bench after NHL action against the Clagary Flames  in Calgary, Alta., Thursday April 9, 2015. Sutter says he has "unfinished business" as he returns to coach the Calgary Flames. THE CANADIAN PRESS/Larry MacDougal
Darryl Sutter has ‘unfinished business’ in return to Calgary Flames

Darryl Sutter has ‘unfinished business’ in return to Calgary Flames

Walter Gretzky talks to people while at the funeral of Celtic music legend John Allan Cameron at St. Isaac Jogues Church in Pickering, Ont., Monday, Nov. 27, 2006. THE CANADIAN PRESS/Nathan Denette
‘A legend in his own right’: Hockey world pays tribute to the late Walter Gretzky

‘A legend in his own right’: Hockey world pays tribute to the late Walter Gretzky

Jordan Spieth follows his approach shot to the ninth green during the second round of the Arnold Palmer Invitational golf tournament Friday, March 5, 2021, in Orlando, Fla. (AP Photo/John Raoux)
Conners builds 1-shot lead at Bay Hill as McIlroy lurks

Conners builds 1-shot lead at Bay Hill as McIlroy lurks

Team Canada skip Brad Gushue makes a shot as he plays Team Ontario at the Brier in Calgary, Alta., Friday, March 5, 2021.THE CANADIAN PRESS/Jeff McIntosh
Brier in the Bubble: Defending champion Gushue beats Epping in opening draw

Brier in the Bubble: Defending champion Gushue beats Epping in opening draw

Switzerland's celebrates after the final match at the Women's Curling World Championship in Silkeborg Denmark Sunday March 24. 2019. The 2021 world women's curling championship is back on the curling calendar. THE CANADIAN PRESS/AP, Ritzau Scanpix - Henning Bagger
Women’s world curling championship back on calendar, added to Calgary bubble

Women’s world curling championship back on calendar, added to Calgary bubble

A guard stands outside the gates of an immigrant holding centre in Laval, Que., Monday, Aug. 15, 2016. Several men at a Montreal-area immigration detention refused food this week as part of a protest aimed at drawing attention to what they say are inhumane conditions and to secure their release.THE CANADIAN PRESS/Graham Hughes
Montreal-area immigration detainees on hunger strike over COVID-19 fears

Montreal-area immigration detainees on hunger strike over COVID-19 fears

Minister of National Defence Harjit Sajjan takes part in a year-end interview with The Canadian Press at National Defence Headquarters in Ottawa on Thursday, Dec. 17, 2020. THE CANADIAN PRESS/Sean Kilpatrick
Sajjan aide emailed military ombudsman about allegations days after meeting in 2018

Sajjan aide emailed military ombudsman about allegations days after meeting in 2018

Most Read