Can you take too much folic acid?

In this article:

• Can you take too much folic acid?
• Symptoms
• Who’s at risk?
• Tips for taking folic acid

In this article

• Can you take too much folic acid?
• Symptoms
• Who’s at risk?
• Tips for taking folic acid

Folate is vitamin B9. Found in leafy greens, citrus fruits, and other foods, this water-soluble B vitamin helps the body make red blood cells and supports cell growth and function. Although folate naturally occurs in some foods and is added to others, some people need extra, so they take folic acid supplements, a synthetic form of folate. Pregnant women need to be especially mindful about getting enough folate because it can help reduce the risk of congenital disorders such as spina bifida in developing fetuses. However, it’s important to take only the recommended amount, and only for the recommended length of time, because it is possible to get too much of a good thing. 

Can you take too much folic acid?

“It is possible to consume too much folic acid, likely from taking in too much daily rather than one big dose,” says Maria D’Iorio, MD, an OB-GYN with Novant Health in Winston-Salem, North Carolina.

It’s most likely to occur from taking high-dose supplements for extended periods of time and not from just eating foods that are high in folate, says Sandi Hamilton, MS, RD, a registered dietitian with Novant Health. For example, one possible way to consume too much folic acid is by taking a prenatal vitamin containing folic acid in addition to another folic acid supplement. In other words, more isn’t always better. 

The body absorbs folic acid into the bloodstream through the intestines. The liver then converts it into other forms of folate. Folic acid is water-soluble, meaning that if you take too much, it will be excreted in your urine.

The amount of folate needed varies. Most adults need 400 micrograms (mcg) daily, although breastfeeding mothers need 500 mcg daily. Pregnant people need even more folate: 600 mcg daily is recommended to reduce the risk of neural tube defects such as spina bifida in developing babies. 

Occasionally, someone will have a folic acid deficiency because they don’t eat enough foods that contain folate or they don’t absorb folic acid well, due to a health condition such as Crohn’s disease, celiac disease, inflammatory bowel disease, or excessive alcohol consumption. In such cases, their healthcare provider might also recommend a folic acid supplement. 

Others who can benefit from supplementation include people with hyperhomocysteinemia, or high levels of homocysteine in the blood, which is linked to an increased risk of cardiovascular disease. Children who take antiepileptic drugs (AEDs) for seizures may need to take folic acid supplements to help control their seizures. People taking methotrexate for rheumatoid arthritis may benefit from taking folic acid to reduce gastrointestinal side effects like nausea, vomiting, and abdominal pain.

The difference between folate and folic acid

Folate is dietary vitamin B. Folic acid is a synthetic form of the vitamin, taken when you can’t get enough from the foods you eat. 

It’s generally best for most people to get folate from the food they eat. Dietary folate is available in many foods, including:

• Dark green leafy vegetables
• Other vegetables, such as asparagus, Brussels sprouts, and broccoli
• Citrus fruits
• Peas, beans, and legumes
• Liver
• Eggs and dairy
• Seafood

Many breads, pastas, and cereal products are fortified with folic acid. However, sometimes it’s hard for people to get all the folate they need from food (even fortified food). In that case, they can turn to folic acid supplements. Usually, a prenatal vitamin will contain the necessary folate for pregnant women, according to D’Iorio. Women at higher risk for pregnancies with neural tube defects, such as a family history of spina bifida, may need a higher dose through the first trimester. 

6 symptoms of too much folic acid

You might wonder if you would even know if you were taking too much folic acid. It might not always be easy to tell. “Many people would not be symptomatic from folic acid excess,” says D’Iorio. “There is no evidence that it would cause spotting or adverse pregnancy effects.”

However, it’s still possible to experience some symptoms or signs of consuming excessive amounts of folic acid. Here are some possible symptoms of taking too much:

1. Digestive issues

One of the most likely side effects of excessive folic acid intake is an upset stomach, including nausea, diarrhea, or abdominal cramps. 

2. Hypersensitivity

Another possible side effect of too much folic acid is hypersensitivity. This may include symptoms such as skin rashes, redness, itching, and trouble breathing. However, this may also indicate an allergic reaction. 

3. Mood changes

Confusion or irritability can also result from taking too much folic acid by mouth, according to the Mayo Clinic. Insomnia is another possible symptom of excessive folic acid intake.

4. Anemia

Taking large amounts of folic acid can mask the effects of a deficiency in a different B vitamin that the body does not produce on its own: B12. Vitamin B12 helps the body make red blood cells and DNA, and keeps blood and nerve cells healthy. Some research suggests that excessively high levels of folate can contribute to a decline in vitamin B12 levels. A vitamin B12 deficiency can lead to anemia, as well as other potential health problems, including damage to the nervous system. The Mayo Clinic suggests taking a supplement that contains the 100% daily recommended value of both vitamin B12 and folic acid.

5. Neurological concerns

Research suggests that excess folic acid poses a risk to the nervous system. Too much folic acid can mask or even worsen the neurologic symptoms of vitamin B12 deficiency. The potential neurologic changes may include cognitive slowing and neuropathy, D’Iorio says. Instead, the body needs the correct balance of folate and vitamin B12. This and anemia are the two most serious consequences of taking too much folic acid. 

6. Kidney problems

Some research indicates that folic acid may help slow the progression of chronic kidney disease. However, high doses of folic acid could be problematic for the kidneys, as other research suggests that a high concentration of folic acid may contribute to acute renal failure. People with kidney disease should discuss the appropriate use of folic acid supplements with their healthcare provider. 

Who’s at risk for folic acid overload?

Anyone who’s taking folic acid supplements should be cautious about taking the appropriate amount, as recommended by their healthcare provider.  

“While we still recommend folic acid supplementation in the pre-conception period and first trimester, it’s important to be mindful of your folic acid intake, especially if you are consuming high amounts of folic acid-fortified products,” D’Iorio says. 

People with certain health conditions and treatments that require supplementation with folic acid should also be mindful. Take the total supplement dosage and the dietary folic acid into account. When shopping for food, look for the “enriched” label that indicates that foods like breakfast cereals contain a certain amount of added folic acid. 

Taking folic acid safely

Before you start taking any news supplements, including folic acid, it’s important to understand if you even need to take one. For example, are you planning to become pregnant? Do you have a deficiency, or are you at risk for a folate deficiency? 

Even though supplements are sold over the counter, there are many potential drug interactions that could occur. “It is important to report the supplements you are taking or have taken to your healthcare provider so they can advise you on what to change or check your blood levels if excessive supplementation is suspected,” Hamilton says. “Lab testing is the best way to determine if folic acid levels in the blood are in the appropriate range.” 

You also need to read labels carefully. According to the National Institutes of Health (NIH) Office of Dietary Supplements, a number of different bottles on the pharmacy shelf can contain folic acid: 

• Prenatal vitamins
• Multivitamins
• Supplements with B-complex vitamins
• Folic acid-only supplements

The dosage amounts can vary. “If you’re at all concerned, I recommend reviewing with your healthcare provider,” D’Iorio says.