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Updated: Jun 23, 2026
Modifying Levels of Maternal Dietary Folic Acid or Choline to Study the Impact of Deficiencies on Offspring Health Outcomes
Published on: June 28, 2024
Blood folate levels: the latest NHANES results
Margaret A McDowell1, David A Lacher, Christine M Pfeiffer
1Centers for Disease Control and Prevention National Center for Health Statistics 3311 Toledo Road, Hyattsville, Maryland 20782, USA.
Insights
Folic acid fortification significantly increased U.S. population folate levels, particularly red blood cell folate. This initiative has improved folate status and reduced risks associated with low folate, especially for women of childbearing age.
Area of Science:
- Nutrition Science
- Public Health
- Biochemistry
Background:
- Folate is an essential vitamin crucial for overall health.
- Low blood folate levels are linked to increased risks of neural tube birth defects.
- Women of childbearing age are a key demographic previously identified with suboptimal folate status.
Purpose of the Study:
- To analyze trends in U.S. population blood folate levels.
- To assess the impact of mandatory folic acid fortification on folate status.
- To report the prevalence of low folate levels in women of childbearing age.
Main Methods:
- Utilized data from the National Health and Nutrition Examination Surveys (NHANES).
- Analyzed red blood cell (RBC) folate for long-term intake and serum folate for recent intake.
- Examined folate levels in the U.S. population aged 4 years and older, with a focus on women aged 15-45 years.
Main Results:
- Significant increases in blood folate levels observed between 1988-1994 and 1999-2000.
- Median RBC folate was 266 ng/mL and serum folate was 12.2 ng/mL in 2005-2006.
- Prevalence of low RBC folate in women of childbearing age was 4.5%; low serum folate was 0.5% in 2005-2006.
Conclusions:
- Mandatory folic acid fortification, implemented in 1998, has demonstrably improved folate status in the U.S. population.
- NHANES data confirm the effectiveness of fortification in enhancing folate levels.
- The fortification strategy appears successful in mitigating risks of folate deficiency, particularly for vulnerable groups like women of childbearing age.
Abstract:
Data from the National Health and Nutrition Examination Surveys. Very large increases in blood folate levels of the U.S. population occurred between 1988-1994 and 1999-2000. Small fluctuations in blood folate levels occurred over the time period 1999-2006. The median red blood cell (RBC) folate level of the U.S. population 4 years of age and older was 266 ng/mL in 2005-2006. The median serum folate level of the U.S. population 4 years of age and older was 12.2 ng/mL in 2005-2006. In 2005-2006, the prevalence of low RBC folate (less than 140 ng/mL) among U.S. women of childbearing age (15-45 years) was 4.5%. In 2005-2006, the prevalence of low serum folate (less than 3 ng/mL) among U.S. women of childbearing age was 0.5%. Folate is an essential vitamin for good health. Women of childbearing age are among the population subgroups that have been shown previously to have low blood folate levels. Low blood folate levels are associated with an increased risk of neural tube birth defects. Beginning in 1998, the Food and Drug Administration (FDA) required the addition of folic acid (a form of folate) to all enriched breads, cereals, flours, corn meal, pasta products, rice, and other cereal grain products sold in the United States. Blood folate data from the National Health and Nutrition Examination Surveys (NHANES) have documented improvements in the folate status of the U.S. population after folate fortification was implemented. Red blood cell (RBC) folate measures long-term folate intake and low levels are associated with adverse health effects. Serum folate reflects recent folate intake and low levels are an early indicator of inadequate folate status. Pre- and postfortification blood folate levels of the U.S. population 4 years of age and older and prevalence of low blood folate among women of childbearing age (15-45 years) are reported.
