Health knowledge and news provided by doctors.

Too Much Folic Acid Could Harm Fetal Brain Warns Study

Timothy Boyer Ph.D.'s picture
Too much folic acid supplementation not recommended according to new study.

According to a new study, researchers find that too much folic acid is just as detrimental as too little.


Folic Acid Is Essential During Pregnancy

Folic acid (the synthetic form of vitamin B9) supplementation is essential for women of child-bearing age due to that it has been found to substantially reduce the risk of neural tube defects, such as spina bifida, in children.

The recommended daily intake of folic acid is 400 micrograms with a maximum daily safe upper limit of 1000 micrograms (or 1 milligram).

Too Much Might Be Too Much Warns Study

However according to a news release from the University Of California-Davis, a new study published in in journal Cerebral Cortex reports that too much folic acid during pregnancy could be harmful to a human fetal brain.

"Addition of folic acid to the diet was a good thing, and I've supported fortification, but there is a 'best amount' of folic acid, and some people may be getting more than is optimal," said Ralph Green, UC Davis distinguished professor of pathology and medicine and co-author of the study.

The concern is based on the published study’s results when pregnant mice were given either a normal amount of folic acid, 10 times the recommended amount, or none. What the study revealed was that the offspring of the mice that received the largest amount of folic acid showed significant brain changes.

"It's not subtle. It's substantial," said Konstantinos Zarbalis, associate professor in the Department of Pathology and Laboratory Medicine and also a corresponding author of the research. "It makes a marked difference in brain structure if you take very high amounts of folic acid."

Follow eMaxHealth on YouTube, Twitter and Facebook.
Please, click to subscribe to our Youtube Channel to be notified about upcoming health and food tips.

In fact, the news release state that “Women who have given birth to a child with neural tube defects or who have certain conditions like epilepsy and take anticonvulsants, have generally been advised to take much higher doses of folic acid.”

"In animal models, we have indications that very high amounts of folic acid can be harmful to brain development of the fetus, and the clinical community should take this indication seriously, to support research in this area to reevaluate the amount of folic acid that is optimal for pregnant women," said Zarbalis.

What To Expect When You Are Expecting With COVID-19

The researchers believe that the problem may lie in the way folic acid is metabolized by the body and have are planning to investigate the phenomenon further to gain a better understanding of the risks too much folate may pose during pregnancy.

For more about the possible risks of too much folic acid, here’s an older story about studies suggesting that high-dose supplementation with folic acid during pregnancy may increase the risk of asthma in children.

Timothy Boyer has a Ph.D. in Molecular and Cellular Biology from the University of Arizona. For 20+ years he has been employed as a freelance health and science writer. Today, with an eye on the latest news, Timothy continues writing about science with a focus on what you need to know for healthier living. For continual updates about health, you can also follow Timothy on Twitter at TimBoyerWrites.

Image Source: Courtesy of Rudy and Peter Skitterians from Pixabay


Excess folic acid during pregnancy harms brain development of mice” University Of California-Davis Health, 5 Oct. 2020.

Deficient or Excess Folic Acid Supply During Pregnancy Alter Cortical Neurodevelopment in Mouse Offspring” Angelo Harlan De Crescenzo, Cerebral Cortex, bhaa248, 30 September 2020.