Last updated on 7-8-2025 by Laïla Boulbayem
Why do we study folic acid intake?
- Folic acid (vitamin B9) is a water-soluble vitamin essential to blood cell production, protein synthesis, and cardiovascular health. It is crucial during pregnancy, supporting fetal brain and spinal cord development while reducing neural tube defect risks (e.g., spina bifida). Folic acid, known internationally as vitamin B9, is also known as Vitamine B11 in Belgium and the Netherlands.
- Dietary sources of folic acid include green leafy vegetables (e.g., spinach, Brussels sprouts, and broccoli), citrus fruits, whole grains, organ meats, yeast, and, to a lesser extent, dairy products, meat, eggs, and potatoes. Additionally, folic acid is commonly added to fortified foods (e.g., breakfast cereals, bread) and present in various supplements.
- A balanced diet generally provides sufficient folic acid. However, the Superior Health Council recommends that pregnant women take a daily supplement of 400 µg of folic acid from four weeks before conception until the twelfth week of pregnancy.
- Despite the widespread availability of folic acid in fortified foods and supplements, excessive intake from supplements should be avoided. High doses may mask a vitamin B12 deficiency and pose potential health risks. The Superior Health Council advises against long-term supplementation exceeding 500 µg/day to prevent neurological risks.
How do we study it?
- The prevalence of inadequate folate intake from food and food + supplements was estimated as the proportion of individuals with an habitual folate intake below the reference values set by the European Food Safety Authority (EFSA): 250 µg folate equivalents per day for older adolescents and adults (older than 15 years), and between 90 µg and 210 µg folate equivalents per day for children and younger adolescents (3–14 years) depending on age.
- The prevalence of excessive folic acid intake from supplements only was estimated as the proportion of the population with a habitual folic acid intake from supplements only above the safety reference values set by EFSA: 1000 µg/day for adults and ranges from 300 to 800 µg/day for children and adolescents depending on age.
- Note: Synthetic folic acid, found in supplements and fortified foods, has a higher bioavailability than the form of folic acid that is naturally occurring in food, namely folate. This means that 1 µg of folic acid from supplements or fortified foods is more efficiently absorbed by the body than 1 µg of folate from food. Therefore, when assessing folate intake from both food and supplements, synthetic folic acid from supplements is converted to folate equivalents using a correction factor of 1.7 (1 µg of folic acid equals 1.7 µg of folate). Folic acid intake from supplements only is directly expressed in µg of folic acid.
- Habitual intake of folic acid and folate was analysed using the SPADE® program. A detailed description of the methodology for deriving the habitual folate intake, the type of reference values used and the age-and-gender-specific values of these references can be found here.
KEY RESULTS
The mean intake of folate equivalents from food in the Belgian population is 203 µg/day and increases to 241 µg/day when food and supplements are taken into account
70% of the population has an inadequate intake of folate equivalents from food. This decreases to 62% when food and supplements are taken into account
Regional differences are observed in the proportion of individuals with inadequate folate intake: 65% in Flanders and 78% in Wallonia have an inadequate intake from food alone
The mean intake of folate equivalents from food was similar in 2014–2015 (201 µg/day) and in 2022–2023 (202 µg/day)
Vegetables and cereals and cereal products each contribute 21% to total folate equivalent intake, followed by dairy products and substitutes, which contribute 9%
Proportion of the population consuming a folic acid-containing supplement
18% of the population in Belgium aged 3 years and older uses a folic acid-containing supplement.
By sex
Mean intake of folate equivalents (µg/day) in the population aged 3 years and older, by sex, Belgium: 2022-2023
- Crude = results weighted for season, age, sex, and socioeconomic status.
- Folate equivalent accounts for the different bioavailability of folate from food and synthetic folic acid found in supplements. Synthetic folic acid, found in fortified foods and supplements, is absorbed more efficiently, with 1 µg of folic acid equaling 1.7 µg folate equivalents.
- The mean intake of folate equivalents from food in the population is 204 µg/day and increases to 241 µg/day when food and supplements are taken into account. 18% of the population uses a folic acid-containing supplement.
- The mean intake of folate equivalents from food is higher in men (219 µg/day) than in women (189 µg/day). This difference remains when also supplements are taken into account and increases to 247 µg/day in men and 235 µg/day in women.
Proportion of the population aged 3 years and older with inadequate folate equivalents intake, by sex, Belgium: 2022-2023
- Crude = results weighted for season, age, sex, and socioeconomic status.
- 70% of the population has an inadequate intake of folate equivalents from food. This decreases to 62% when food and supplements are taken into account.
- The proportion of the population with inadequate folate equivalents intake from food is higher in women (77%) than in men (62%). This difference remains when supplements are included: 67% of women compared to 57% of men have inadequate folate equivalent intake from food and supplements.
Excessive folic acid intake the population aged 3 years and older, by sex, Belgium: 2022-2023
The proportion of the Belgian population with an excessive habitual folic acid intake from supplements, exceeding the EFSA safety level, is 0.3% in both men and women, as well as overall.
By age
Mean intake (µg/day) of folate equivalents in the population aged 3 years and older, by age, Belgium: 2022-2023
- Folate equivalent accounts for the different bioavailability of folate from food and synthetic folic acid found in supplements. Synthetic folic acid, found in fortified foods and supplements, is absorbed more efficiently, with 1 µg of folic acid equaling 1.7 µg folate equivalents.
- Crude = results weighted for season, age, sex, and socioeconomic status.
- Older adults (65 years and above) do not include those residing in care facilities, hospitalised individuals, or those who would have required significant assistance during interviews (e.g., people with cognitive impairments).
- The mean intake of folate equivalents from food shows an age-related increase, ranging from 175 µg/day in children (3-9 years) to 220 µg/day in older adults (65 years and above). When supplements are also taken into account, the intake rises to 197 µg/day in children, 203 µg/day in adolescents (10-17 years), 252 µg/day in adults (18-64 years), and 262 µg/day in older adults.
Proportion of the population aged 3 years and older with inadequate folate equivalent intake, by age, Belgium: 2022-2023
- Crude = results weighted for season, age, sex, and socioeconomic status.
- Older adults (65 years and above) do not include those residing in care facilities, hospitalised individuals, or those who would have required significant assistance during interviews (e.g., people with cognitive impairments).
- Based on intake from food alone, the proportion of individuals with inadequate folate intake is 24% in children, 71% in adolescents, 76% in adults, and 70% in older adults.
- When supplements are also taken into account, inadequate intake of folate acid equivalents remains prevalent: the percentages drop slightly to 22%, 67%, 67%, and 64%, respectively.
Proportion of the population aged 3 years and older with excessive folic acid intake, by age, Belgium: 2022-2023
The proportion of the Belgian population with an excessive folic acid intake from supplements, is 6% in children (3-9 years), 0,2% in adolescents, and 0,5% in adults (18-64 years) and older adults (65 years and above).
By educational level
Mean folate equivalent intake (µg/day) in the population aged 3 years and older, by educational level, Belgium: 2022-2023
- Folate equivalent accounts for the different bioavailability of folate from food and synthetic folic acid found in supplements. Synthetic folic acid, found in fortified foods and supplements, is absorbed more efficiently, with1 µg of folic acid equaling 1.7 µg folate equivalents.
- Crude = results weighted for season, age, sex, and socioeconomic status.
- The educational level is calculated at the household level by considering the highest diploma obtained by: (i) the respondents or their partner for adults (aged 18 years and above), or (ii) the father and mother (or carer, if applicable) for children and adolescents (aged 3 to 17 years). However, for simplicity, we refer to the educational level of individuals rather than the educational level of their households.
- The intake of folate equivalents from food is lower in individuals with a low educational level (195 µg/day) compared to those with a medium (203 µg/day) or high educational level (217 µg/day).
- When supplements are taken into account, the intake rises to 229 µg/day, 241 µg/day, and 258 µg/day in individuals with low, medium, and high educational levels, respectively.
By region
Mean folate equivalent intake (µg/day) in the population aged 3 years and older, by region, Belgium: 2022-2023
- Folate equivalent accounts for the different bioavailability of folate from food and synthetic folic acid found in supplements. Synthetic folic acid, found in fortified foods and supplements, is absorbed more efficiently, with1 µg of folic acid equaling 1.7 µg folate equivalents.
- Crude = results weighted for season, age, sex, and socioeconomic status.
- Brussels is excluded from the regional comparison due to an insufficient number of participants, but is included in the national data for Belgium.
- The mean intake of folate equivalents from food is higher in Flanders (216 µg/day) than in Wallonia (183 µg/day).
- This regional difference persists when supplements are included, with a total intake of 262 µg/day in Flanders compared to 216 µg/day in Wallonia.
Proportion of the population aged 3 years and older with inadequate folate equivalent intake, by region, Belgium: 2022-2023
- Crude = results weighted for season, age, sex, and socioeconomic status.
- Brussels is excluded from the regional comparison due to an insufficient number of participants, but is included in the national data for Belgium.
- Clear regional differences are observed in the proportion of individuals with inadequate folate intake: 65% in Flanders and 78% in Wallonia have an inadequate intake from food alone.
- When supplements are taken into account, these proportions decrease to 57% and 70%, respectively.
By year
Mean folate equivalent intake (µg/day) in the population aged 3 to 64 years, by year, Belgium: 2022-2023
- Folate equivalent accounts for the different bioavailability of folate from food and synthetic folic acid found in supplements. Synthetic folic acid, found in fortified foods and supplements, is absorbed more efficiently, with1 µg of folic acid equaling 1.7 µg folate equivalents.
- Crude = results weighted for season, age, sex, and socioeconomic status.
- The mean intake of folate equivalents from food was similar in 2014–2015 (201 µg/day) and in 2022–2023 (202 µg/day).
- When supplements are included, the intake increases slightly to 237 µg/day and 239 µg/day, respectively, showing no notable change over time.
Proportion of the population aged 3 to 64 years with inadequate folate intake, by year, Belgium: 2022-2023
- Crude = results weighted for season, age, sex, and socioeconomic status.
- The proportion of individuals with inadequate folate intake from food was similar in 2014–2015 (71%) and 2022–2023 (70%).
- When supplements are included, the proportion slightly decreases to 63% in 2014–2015 and 62% in 2022–2023, showing no significant change over time.
Contribution of food and supplements
Contribution of foods and supplements to folate intake, in the population aged 3 years and older, Belgium: 2022-2023
- Crude = results weighted for season, age, sex, and socioeconomic status.
- Vegetables and cereals and cereal products each contribute 21% to total folate equivalent intake, followed by dairy products and substitutes, which contribute 10%.
- Supplements account for 6% of the total folate equivalent intake.
Please cite this page as: Sciensano. Micronutrients: Vitamin B11 Folic Acid, Food Consumption Survey 2022-2023, June 2025, Brussels, Belgium, https://www.sciensano.be/en/results-national-food-consumption-survey-2022-2023/micronutrients-vitamins/vitamin-b11-folic-acid