Folic acid amounts in Canadian fortified foods versus labels and databases
What it found
Lab tests on 89 common Canadian foods found much more total folate and synthetic folic acid than official databases or product labels showed.
The gap was seen across most food types except cooked pasta.
What they found
More folate than listed
Across 89 foods, the average total folate measured in the lab was 65% higher than what the national nutrient database reported. For most food groups, the tested amount was about 167% of the database value, plus or minus 54%.
Extra synthetic folic acid
The amount of synthetic folic acid measured by mass spectrometry averaged 188% of the database values, plus or minus 94%. Cookies had the biggest gap, with tested levels at 251% of the database number, plus or minus 89%.
Labels also underestimated folate
For breads, buns and rolls, and ready-to-eat cereals, lab tests found 87% more total folate than the product labels stated. Cooked pasta was the exception, where the label number was 69% higher than what the lab found after cooking.
Why manufacturers add extra
Manufacturers often add more folic acid than the minimum required level. This is done to make sure the food still meets the rules throughout its shelf life and to account for differences that happen during production and testing.
Two lab methods compared
A microbe-based test measured total folate, while a mass spectrometry method measured only the synthetic folic acid. For rolls, buns and crackers, the microbe test gave results 21% to 24% higher than the mass spectrometry method, likely because it also picked up naturally occurring folate.
What the authors conclude
- They conclude that actual folate and folic acid levels in fortified foods remain well above mandated amounts even 20 years after fortification began.
- They advise against relying only on dietary databases or food labels to judge whether people are getting enough folate.
- They suggest that blood measurements give a better picture of true folate status than estimates based on food records.
How it was done
Canada required white flour and grain products to have added folic acid starting in 1998 to help prevent birth defects. Ten years later, researchers found the official nutrient database listed less folate than foods actually contained, so they checked again after 20 years.
Researchers bought 89 of the most commonly purchased fortified foods across seven categories from stores in Toronto and Montreal between 2019 and 2021. They used lab methods to measure both total folate and the specific synthetic folic acid added during manufacturing. They then compared those results to values in the 2015 Canadian Nutrient File and to numbers printed on product labels.
What it can’t tell you
- This work only measured nutrients in foods bought in two Canadian cities, so it cannot show exactly how much folate any individual person takes in.
- Because the study looked at food composition rather than health outcomes, it cannot show whether these higher amounts affect people's health in any way.
- The shopping data used to pick which foods to test came from 2001 and 2007, so buying habits may have changed since then.
Who paid
- Conflicts
- The authors have no conflicts of interest relevant to this article to disclose.
- Authors work at
- The Hospital for Sick Children, Canada; University of Toronto, Canada; and Nutrition Evidence Center, USA
The paper
- Title
- Folate and synthetic folic acid content in Canadian fortified foods two decades after mandatory fortification
- Type
- Study
- Summarised from
- Full text
- Cite
- Khanna S, Aufreiter S, MacFarlane A, Shakur Y, O'Connor D (2024). Folate and synthetic folic acid content in Canadian fortified foods two decades after mandatory fortification. Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme. doi:10.1139/apnm-2024-0063Free full textPubMed 38728750DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error