Folate deficiency virtually nonexistent among Canadians

Researchers at The Hospital for Sick Children (SickKids) and The Children’s Hospital of Eastern Ontario Research Institute are the first in over three decades to examine folate status on a national scale with a subset of women of childbearing age. The study is published in the December 13 advance online edition of the Canadian Medical Association Journal (CMAJ). 

Over 5,000 Canadians of varying age, sex and socioeconomic standing were assessed.  Less than one per cent demonstrated folate deficiency and 40 per cent demonstrated high concentrations of folate.  The researchers also found that 22 per cent of women of childbearing age remain below the level that is considered optimal for prevention of neural tube defects. While this latter number may sound high, it is important to note that not all women of childbearing age will become pregnant, explains Dr. Deborah L. O’Connor, Director of Clinical Dietetics at SickKids.  “Some of these women have already completed having children, while others might not be able to – or want to – become pregnant.”

“A better understanding of the subset of women not yet reaching blood folate levels that are maximally protective against neural tube defects is needed to develop new innovative strategies to reduce the risk of birth defects in this group,” she says. 

In 1998, folic acid fortification of the Canadian food supply was adopted as one of the strategies to minimize the risk of neural tube defects and has since been linked to a 46 per cent reduction in the prevalence of these birth defects.  Improving maternal folate status is thought also to reduce the risk of congenital heart disease and oral clefts. Health Canada also continues to recommend that healthy women capable of becoming pregnant consume a multi-vitamin supplement containing 400 ug folic acid for at least three months prior to conceiving and through the first trimester of pregnancy.   

“Given that folate deficiency is virtually nonexistent and that high blood folate concentrations are reported in the Canadian population in our study, it seems prudent for manufacturers to remove folic acid from multi-vitamin supplements designed for children and men,” says O’Connor.  While data are inconclusive at this time, there remains speculation that very high levels of folic acid may be associated with adverse effects such as increased risk of colorectal cancer.  Additional research and continued monitoring of the folate status of Canadians and its health outcomes are required.