The United States and Canada began enriching grains with folic acid starting in 1996 and 1997, respectively. The FDA made this mandatory in 1998. They enriched it at levels we could never hope to get from eating a good diet.

Why Folic Acid?

The FDA chose folic acid because it is an effective way to reduce a type of birth defects called neural tube disorders (NTDs). NTDs include debilitating diseases like spina bifida, a complication of the baby’s spinal column. Doctors found that there were high rates of NTDs in areas where it is challenging to find nutritious food. Policymakers stepped in and tried to decrease NTDs nationwide. Adding folic acid was incredibly effective in reducing NTDs by 20-50 percent. (The literature varies in the exact percentage.)

What’s so Great About Folate?

Folate, an important nutrient found naturally in fruits and vegetables, has an important role in healthy cell growth. Folic acid is the synthetic, or manmade, version of folate and can help supplement if a person is not getting enough folate solely from his or her diet. Folic acid has two crucial functions:

  • It reduces NTD complications.
  • It is essential for brain function across all ages, possibly slowing or even preventing brain deterioration.

Folate: The More the Better?

If a little folate is good, is a lot of folate better? Unfortunately, I don’t think so. Policymakers hoped that would be true, but there may be a catch.

Epidemiologists watch health trends and hope to identify possible exposures that can lead to disease. They noticed something concerning: After 1996, the rates of colorectal cancer began to increase. Since the increase was statistically different from previous rates, they began to investigate this trend.

First, they evaluated whether new screening methods were the reason for the increase. They thought perhaps doctors were finding more cases of cancer simply because they were looking harder.

Is There a Link Between Folic Acid and Colorectal Cancer?

Unfortunately, an increase in cancer screening did not account for the higher cancer rate. While we still need more research to determine the link between folic acid and colorectal cancer, scientists do have one hypothesis. They propose that folic acid, this amazing supplement that helps our cells grow, also helps cancer cells grow.

The hypothesis states that anyone with a precancerous lesion would find that the cancer was growing with help from the folic acid supplements. Folic acid is not responsible for the cancer itself, but it might boost a precancerous lesion to turn into cancer faster and quicker. Though this is just a hypothesis, it’s certainly concerning.

Research has linked folic acid to other cancers as well, but a lot is still unknown about the relationship of folic acid and these cancers. We need to be careful when we alter our food in major ways.

 Folic Acid Supplements and Pregnant Women

It is very important to note that physicians (and the research) absolutely support folic acid supplements for anyone pregnant or breastfeeding. The recommended dose of folic acid is 400-600 micrograms in that situation, much less than the folic acid fortification in grains. Some breakfast cereals, nutrition bars and other fortified foods deliver up to 800 micrograms of folic acid.

Additionally, there is research that supports that low doses of folic acid can reduce your risk of heart attack and stroke.

Folic Acid: The Bottom Line

Epidemiology is a challenging science because we are studying human behavior and disease, and neither always behaves as it should. It is hard to determine what is dangerous vs. what seems to be dangerous. I believe we should focus on trying to get folate through leafy greens and fruits and supplements when our physicians recommend it. We should stay away from additional supplementation until we fully understand the consequences. We should also be mindful that we are what we eat, and pay attention to policies that affect our foods.


Kate Burdekin is a clinical research associate with Inova Dwight and Martha Schar Cancer Institute. She coordinates the administrative and regulatory aspects of clinical trials. Kate has a BS in neurobiology and physiology from University of Maryland. She is currently working to complete a master’s degree in public health with a concentration in epidemiology and biostatistics from University of Southern California.