Impact of excess folic acid on pregnancy
Research shows that excess folic acid during pregnancy is linked to impaired growth of the baby in the womb and a higher chance that the baby will develop insulin resistance, diabetes, asthma, and obesity later in life. Taking over 1,000 micrograms of folic acid in the months before and after conception may also slow brain development in children, one study shows.
Having extremely high levels of folic acid during pregnancy can also increase the child’s risk of developing autism. Excess folic acid combined with excess vitamin B12 increases this risk by 17.6 times.
Potential causes of excess folic acid
Excess folic acid comes from taking too many supplements with a very high dose of this vitamin and too many folic acid-fortified foods. It doesn’t happen when you eat foods that are naturally rich in folate. Genetics may also predispose somebody to absorb more folate from foods or metabolize it at a slower rate, which could lead to excess folic acid in the body.
Symptoms of excess folic acid
Taking a folic acid supplement dose of over 1,000 micrograms per day can cause the following side effects:
- Upset stomach
- Nausea
- Diarrhea
- Irritability
- Confusion
- Skin reactions
- Seizures
Excess folic acid may also increase the risk for serious health problems, including cancer and heart attack (in people already at a higher risk of heart disease).
Taking large amounts of folic acid supplements can also conceal a vitamin B12 deficiency and worsen symptoms of the deficiency.
Diagnosis of excess folic acid
You can check your folic acid status with a blood test. Tell your doctor about any medications you are taking before the test, as some drugs can interfere with the results. If your test shows that you have very high amounts of folic acid in the blood, you will be diagnosed with excess folic acid.
Treatment
Work with your doctor to choose a prenatal supplement that’s right for your body to ensure that you have safe levels of folic acid before you conceive. Some women are recommended to take higher doses of folic acid supplements if they are at risk of having a pregnancy affected by neural tube defects.
To decrease your folic acid intake, you should also check nutritional labels on foods you buy, as folic acid is added to many foods (cereals, flour, bread, pasta, baked goods, and crackers). Choose options that don’t have the vitamin added to them. Focus instead on getting your fill of folate from foods where it is found naturally.
Folate-rich foods include:
- Spinach
- Brussels sprouts
- Broccoli
- Asparagus
- Beans
- Peanuts
- Sunflower seeds
- Seafood
- Eggs
- Whole grains
You can meet with a LEVY nutritionist to create a personalized meal plan to make sure you meet your specific dietary needs to boost your fertility and chances of a healthy pregnancy and baby.
- Folate – Fact Sheet for Consumers. U.S. Department of Health & Human Services – National Institutes of Health; Office of Dietary Supplements. Accessed 12 January 2023.
- Folate (folic acid). Mayo Clinic. Accessed 12 January 2023.
- Selhub J and Rosenberg IH: Excessive folic acid intake and relation to adverse health outcome. Biochimie. 2016;126:71-78.
- Smith AD et al.: Is folic acid good for everyone? Am J Clin Nutr. 2008;87(3):517-33.
- Valera-Gran D et al.: Effect of maternal high dosages of folic acid supplements on neurocognitive development in children at 4-5 y of age: the prospective birth cohort Infancia y Medio Ambiente (INMA) study. Am J Clin Nutr. 2017;106(3):878-887.
- Too Much Folate in Pregnant Women Increases Risk for Autism, Study Suggests. Johns Hopkins Bloomberg School of Public Health. Accessed 12 January 2023.
- 4 Potential Side Effects of Too Much Folic Acid. Healthline. Accessed 12 January 2023.
- Keating E et al.: Excess perigestational folic acid exposure induces metabolic dysfunction in post-natal life. Journal of Endocrinology. 2015;224(3):245-259.
- Taking too much folic acid while pregnant may put daughters at risk of diabetes and obesity. Science Daily. Accessed 12 January 2023.
- Harlan De Crescenzo A et al.: Deficient or Excess Folic Acid Supply During Pregnancy Alter Cortical Neurodevelopment in Mouse Offspring. Cerebral Cortex. 2021;31(1):635-649.
- Folic Acid – Uses, Side Effects, and More. WebMD. Accessed 12 January 2023.
- Xu X et al.: Association of folate intake with cardiovascular-disease mortality and all-cause mortality among people at high risk of cardiovascular-disease. Clinical Nutrition. 2022;41(1):246-254.
- Folic acid. U.S. Department of Health & Human Services – Office on Women’s Health. Accessed 12 January 2023.
- Folic acid – test. University of California San Francisco Health. Accessed 12 January 2023.
- Lamers Y et al.: Periconceptional intake of folic acid among low-risk women in Canada: summary of a workshop aiming to align prenatal folic acid supplement composition with current expert guidelines. The American Journal of Clinical Nutrition. 2018;108(6):1357-1368.
- Folate (Folic Acid) – Vitamin B9. Harvard T.H. Chan School of Public Health. Accessed 12 January 2023.
