People who live in countries, including Canada, that require food makers to add folic acid to certain items may be consuming excessive amounts of the B vitamin, new research suggests.
The findings add to the brewing controversy over the potential health risks of high folic-acid intake after several studies found it may accelerate cancer growth in certain predisposed individuals.
In the new study, published yesterday in the journal BMC Public Health, researchers in Ireland found that voluntary folic-acid food fortification may supply the population with sufficient – but not excessive – amounts.
Unlike Canada and the United States, Ireland and Britain don’t require food manufacturers to add folic acid to white flour, enriched pasta and cornmeal products. But some food companies voluntarily add folic acid to certain items, such as cereals.
Researchers set out to determine how much folic acid people may be getting from such voluntary measures by looking at levels present in 50 blood donors, 20 new mothers who had caesarean sections and 20 newborns.
They detected folic acid in nearly all subjects, including the group of mothers and newborns, who had fasted for at least eight hours before their blood samples were taken.
Although the levels were low, researchers said the fact the vitamin was present in the fasting women indicates a constant, habitual exposure that may increase the potential of health problems in at-risk individuals. Mandatory folic-acid fortification programs may further raise those risks, they said.
Mary Rose Sweeney, lecturer in health systems research at Dublin City University and lead author of the study, said the findings are too preliminary for researchers to recommend any policy changes or health guidelines. But she said it’s important to take note that too much folic acid may not be a good thing.
“We have to pause and say ‘Let’s flag this for policy makers worldwide,’ ” Dr. Sweeney said in a telephone interview yesterday.
Canada began its fortification program in 1998 and the Public Health Agency of Canada has said there has been a marked decrease in the number of babies born with spina bifida and other neural-tube defects as a result. Women planning to conceive and those in the first 12 weeks of pregnancy should take 0.4 milligrams of folic acid a day, according to the agency. But the Society of Obstetricians and Gynaecologists of Canada recommends women with health conditions such as diabetes, obesity or a history of pregnancy with neural-tube defects take five milligrams a day.
It has been urging the government to increase the amount of folic acid added to fortified foods.
Folate, the naturally occurring form of folic acid, is found in leafy greens and other vegetables and fruits.
Since women may fail to take supplements or get the proper amount for any number of reasons, many countries have opted for mandatory folic-acid fortification in the food supply. As a result, entire populations are exposed to increased amounts.
The Spina Bifida and Hydrocephalus Association of Canada said the fortification program is critically important and can help ensure aboriginal women and women living in lower-income areas are getting the proper amounts.
“The risk [of taking folic acid] is not nearly as high as not taking it,” said Jody Stadnyk, the association’s national executive director and chief executive officer.
Yet a growing body of research has found a link between high intakes of folic acid and a possible increased risk for colon or other types of cancer. Researchers don’t yet have all the answers, but they believe high consumption of folic acid could speed up the growth of cancerous tumours.
The fear of many scientists researching the potential downside to folic acid is that women planning to conceive and others who need it may decide not to take it.
“The last thing we want this paper to do is create a fear you shouldn’t be taking [folic acid] now,” Dr. Sweeney said.
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