Taking Too Much Folic Acid During Pregnancy Increases Risk of Diabetes and Obesity Among Daughters

Folic Acid TabletsAlthough the fortification of grain foods such as bread and cereal with folic acid has prevented 1,300 neural tube defects annually, mothers who take excessive amounts of the supplement while pregnant may increase the risk of diabetes and obesity later in life among their daughters. The new study published in the Journal of Endocrinology reveals the need to establish a safe upper limit of folic acid intake for pregnant women.

Folic acid is a form of the water-soluble vitamin B9 that helps the body make healthy new cells. Folate, the naturally occurring form of the vitamin, is available through food sources such as spinach and other dark leafy greens, liver, yeast, asparagus, and Brussels sprouts. The synthetic form, folic acid, is found in fortified foods and supplements. Folate deficiency increases the risk of neural tube defects (NTDs) such as spina bifida and anencephaly.

For the present study, researchers from the Faculty of Medicine of the University of Porto and the Catholic University of Portugal sought to examine whether high folic acid exposure during pregnancy induces metabolic dysfunction in offspring later in life.

Using a rodent model, the researchers gave rats 20 times the recommended daily amount of folic acid during the mating, pregnancy, and lactation periods. The researchers also monitored the body weight and food and fluid intake of the rats and their offspring.

Rats that consumed excessive amounts of folic acid during pregnancy gave birth to offspring that exhibited irregular feeding behavior and became overweight,  insulin resistant, and adiponectin deficient during adulthood. Adiponectin is a hormone that protects them against diabetes and obesity. Female offspring exhibited more pronounced symptoms.

Conversely, rats that consumed recommend amounts of folic acid during pregnancy generally gave birth to offspring that grew into healthier adults.

The World Health Organization (WHO) currently recommends pregnant women consume 0.4 milligrams of folic acid daily and women with a family history of neural tube defects consume ten times the amount, with 5 milligram supplements widely available. Few studies, however, have investigated the safe upper limit of folic acid intake among pregnant women.

Says lead author Professor Elisa Keating of the Department of Biochemistry:

“While taking a minimum of 0.4mg of folic acid per day is essential when pregnant, our study shows that it is possible to have too much of a good thing. Considering the increasing amount of folic acid consumed during pregnancy through fortified foods, multivitamin pills and supplements, the search for a safe upper dose of folic acid is urgently needed.”

Comments Keating on the findings of the research, “Our study clarifies the potential effects of excess folic acid exposure and may play an important role on rethinking current public health policies surrounding folic acid supplementation.”

The researchers plan to further investigate the mechanisms by which folic acid affects the metabolism of rat offspring and how to apply the findings to human health recommendations.

Two recent studies found that less than one in three women supplement with folic acid before pregnancy and that sun exposure may reduce folate levels in women.


Excess perigestational folic acid exposure induces metabolic dysfunction in post-natal life:
Taking too much folic acid while pregnant may put daughters at risk of diabetes and obesity:

Image Credits

Folic Acid Tablets:

F Is for Fish Handprint Craft

F Is for Fish Handprint Craft

Premature Infant with CPAP

Women with History of Spontaneous Preterm Birth at Increased Risk of Cardiovascular Disease