A Spotlight on Folic Acid

A cup of cooked lentils contains 358 micrograms of folate.

In the late 1920s, the London School of Medicine for Women graduated a brilliant student named Lucy Wills. This newly minted physician embarked on a trip to Bombay to investigate reports of anemic female laborers whose condition seemed to be exacerbated by childbirth. Thinking the anemia could be a sign of a nutritional deficiency, she fed her patients Marmite, which at the time was a fad among British and Australian health nuts. It seemed to help, and because she didn’t know which chemicals in Marmite were responsible for her patients’ improvement, she called that unknown ingredient the Wills factor — which we now know is folic acid.


Prenatal folic-acid supplements are thought to prevent 50 to 75 percent of neural tube defects.


January 8 marked the start of Folic Acid Awareness Week. Folic acid is essential in cell division, so we need it in order to grow or simply to repair damaged tissues. It is especially important that anyone who might become pregnant consumes at least 400 micrograms of folic acid daily, as it can help prevent certain types of birth defects.

Neural tube defects, including anencephaly and spina bifida, occur in about 1 in 1,000 births, and can affect an embryo when it is just a few weeks old, often before pregnancy is even detected. Anencephaly is an especially tragic and usually fatal condition in which an embryo fails to develop parts of its brain or skull. The prognosis for spina bifida is better — some people with spina bifida are unable to walk, while other cases are so mild that they might never be diagnosed.

Because most pregnancies are unintended, adequate folic-acid intake is important for anyone who might become pregnant. Prenatal folic-acid supplements are thought to prevent 50 to 75 percent of neural tube defects, probably by assisting DNA synthesis. According to the Centers for Disease Control and Prevention, synthetic folic acid — in a supplement or in a fortified product such as cereal — is your best bet, and might be absorbed more easily than folic acid found naturally in foods. However, foods that are naturally rich in folic acid are an important aspect of good nutrition. When folic acid appears in foods, it is called folate; this form is found in dark leafy greens, citrus fruits, and legumes (such as beans, dried peas, and lentils). According to the U.S. Department of Agriculture:

  • one cup of cooked lentils contains 358 micrograms of folate
  • one cup of cooked pinto beans contains 294 micrograms of folate
  • one cup of cooked spinach contains 263 micrograms of folate

These are the kinds of foods everyone should strive to include in a healthful diet, so it’s great to eat them whether or not you are intending to become pregnant (or are even capable of doing so!). Lentil soup, a bean burrito, saag paneer, and spinach lasagna are all delicious, folate-rich meals.

Neural tube defects have sometimes disproportionately affected pregnancies of women whose diets included large amounts of corn; a Texas outbreak was traced to corn tortillas. Corn crops can be damaged by an insect called the European corn borer, which paves the way for infection by molds from the Fusarium genus. These molds produce toxins called fumonisins, which can interfere with the body’s ability to absorb folate. A type of genetically engineered corn, called Bt corn, produces pesticidal proteins that kill the European corn borer, protecting the crops from damage. Consequentially, Bt corn is much lower in fumonisins than its non-engineered counterparts. Some people view genetically engineered foods with suspicion and choose to eat organically grown foods, which according to USDA standards cannot be genetically engineered. However, Bt corn is safe for human consumption (and a sprayable, but less effective, form of Bt has been used for decades by organic growers). While there are many good reasons to eat organics, there are also advantages to the move toward Bt corn. (Sixty-five percent of U.S. corn crops contain the Bt gene.)

Getting adequate folic acid isn’t difficult. Whether you take a folic-acid supplement, eat foods fortified with folic acid, or incorporate more folate-rich whole foods into your diet, you’ll be taking a step forward to improve your nutrition — and, if you happen to get pregnant, you’ll reduce the risk of birth defects.

2 thoughts on “A Spotlight on Folic Acid

    • Writing this post made me hungry for spinach lasagna and lentil soup. So I went to the store and bought ingredients for both. Yum!

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