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Can You Take Too Much Folic Acid?

Katlyn Joy |23, February 2015


In recent years, there has been a big push to get folic acid into the diets of women of childbearing years. It is vital in preventing neural tube defects in offspring, which includes disorders such as spina bifida.

The World Health Organization has set minimum standards for women of childbearing age, regardless of their intention to become pregnant, to get 400 to 800 mcg of folic acid each day. For women with a family history of neural tube birth defects the amount is boosted to 4000 mcg daily.

However, a new angle in the folic acid discussion has been uncovered with the publication of a new study in the Journal of Endocrinology. This study takes a look at what happens when women take more than the recommended amounts of the nutrient.

Researchers from the Faculty of Medicine of the University of Porto and the Catholic University of Portugal gave rats 20 times the recommended amounts of folic acid throughout mating, gestation and lactation.

This study is important, as the news of the importance of folic acid in a woman's diet has affected fortification of many common food items as well as spawning an industry of supplements. The need to know a safe upper limit is critical, and this study is a first step in that direction.

Lead author of the study, Professor Elisa Keating states, "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."

"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 findings of the study were concerning as the offspring of the rats in adulthood became overweight and insulin dependent. The rats had abnormal eating patterns. The rat offspring also had a deficiency in adiponectin, a hormone that protects against obesity and diabetes.

The problems of the offspring were more pronounced in females. However, when the rats were given the recommended amounts of folic acid, the negative results were not observed.

Researchers are concerned that many women may think if a little is good, more is better and not divulge to their physicians that they are taking higher supplementation of folic acid. Indeed, supplements containing 25 to 50 times the recommended level of folic acid are readily available for sale.

The researchers will continue to study the mechanisms by which folic acid affects rat offspring's metabolism and investigate the applications to human health.

Folic Acid in the Diet

Folic acid is a B vitamin. Since folic acid is water-soluble, it leaves the body through urination, and a continual supply of the vitamin is needed.

Folic acid can be found in breakfast cereals, which have been fortified, sometimes to 100 percent of the recommended daily allowance, breads, flours, pastas, cornmeal, and white rice. It's also found in dark green leafy vegetables, dried beans and peas, citrus juice and fruits.

The website for the National Institutes of Health states, "Too much folic acid usually doesn't cause harm, because the vitamin is regularly removed from the body through urine."

Of course, the new research has some conflicting information to this. To be safe, make certain you don't take supplementation beyond the recommended levels.

On, the site gives some different advice. "You can't get too much folic acid from foods that naturally contain it.

However, unless your doctor tells you otherwise, do not consume more than 1,000 mcg of folic acid a day. Consuming too much folic acid can hide signs that a person is lacking vitamin B12, which can cause nerve damage. Lacking vitamin B12 is rare among women of childbearing age. Plus, most prenatal vitamins also contain B12 to help women get all that they need."

This site also states, "Also, even if you eat a healthy, well-balanced diet, you might not get all the nutrients you need every day from food alone. In the United States, most women who eat foods enriched with folic acid are still not getting all that they need. That's why it's important to take a vitamin with folic acid every day."

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