Canadian mothers and their babies aren't getting enough vitamin D and should increase their daily intake after consulting a doctor, the Canadian Paediatric Society said Monday.

But Health Canada issued its own statment, advising that the proper studies haven't been done to warrant an increase in vitamin D intake or to test its safety.

The Canadian Paediatric Society says pregnant or breastfeeding women should talk to their doctor about taking a vitamin D supplement of 2000 IU per day.
(CBC)

"Studies have confirmed the high prevalence of vitamin D deficiency among pregnant and lactating women and their breastfed infants, especially in northern latitudes," the paediatric society said in a report. "They also suggest that much higher amounts of vitamin D supplementation may be necessary than those recommended by Health Canada for pregnancy and lactation to achieve vitamin D sufficiency during this period."

Pregnant or breastfeeding women should talk to their doctor about taking a supplement of 2000 international units, or IU, per day, the paediatric society said.

In its report, published in this month's issue of the journal Paediatrics & Child Health, the paediatric society also recommends that babies who are at risk of vitamin D deficiency — such as those with dark skin, who have limited exposure to the sun, or whose mothers are vitamin D deficient — also get extra vitamin D during the winter, regardless of where they live.

Maternal vitamin D levels during pregnancy and breastfeeding, which many studies have found to be in low in Canadians, may influence the health status of the child later in life, according to the report. Low levels can lead to decreased bone density, an exacerbation of asthma and susceptibility to type 1 diabetes.

"Intervention trials have demonstrated that supplementation with vitamin D or its metabolites may improve blood glucose levels in diabetics and decrease symptoms of rheumatoid arthritis and multiple sclerosis," the report reads.

The paediatric society concedes that few studies have been conducted on pregnant and breastfeeding women involving use of high levels of vitamin D. "However, a recent risk assessment based on a review of relevant, well-designed clinical trials of vitamin D in healthy adults showed an absence of toxicity in trials that used vitamin D dosages greater than or equal to 250 µg/day," it reads.

(Ten thousand IU is equivalent to 250 micrograms, also written as 250 µg.)

Health Canada isn't convinced. It issued an information update on vitamin D Monday, saying that the recommendations of various health groups are "premature" and "that a comprehensive review that looks at both benefits and safety needs to be undertaken before the department can issue a revised recommendation."

"The United States Institute of Medicine (IOM) establishes nutrient reference values, which are used by Health Canada to set policies and standards," Health Canada said. "Until an update of the Dietary Reference Intakes for vitamin D is issued by the IOM, Health Canada continues to recommend 200 IU of vitamin D per day for adults 19 to 50 years of age, including pregnant and lactating women." 

Health Canada also advises that everyone over the age of 50 take a daily supplement of 400 IU of vitamin D.

It warned that taking more than 2000 IU a day from all sources of vitamin D could lead to health problems and that Canadians should speak to their health professional before increasing their vitamin D intake above this threshold.