Folate: Benefits, Immune Support and How Much You Need

Folate is a B vitamin your body needs to make DNA and to help your cells divide [1]. That makes it important anywhere your body is building new cells, from red blood cells to immune cells to a growing baby during pregnancy [1].

What is folate?

Folate, also called vitamin B9, is a B vitamin that's found naturally in many of the foods we eat, especially leafy greens, beans and citrus fruits [1]. You'll hear three names for it, and it helps to know the difference.

• Folate: the form found naturally in food [1].
• Folic acid: the manmade form used in fortified foods and most supplements. Your body has to convert it before it can use it [1] [2].
• Methylfolate (5-MTHF): the active form. It's the main form of folate in food and the form that normally travels in your blood [2].

You'll often see folate measured in mcg DFE, which stands for dietary folate equivalents. That's because your body absorbs folic acid more easily than the folate in food, so DFE puts them on the same scale. For example, 240 mcg of folic acid and 400 mcg of food folate both equal 400 mcg DFE [1].

What does folate do for the body?

Folate's best-known job is helping your body make DNA and helping your cells divide [1].

Folate is important to four things inside the human body: new cells and DNA, the blood, healthy pregnancy, and the immune system. Let's take each one individually.

• New cells and DNA: Your body needs folate to make DNA and other genetic material, and for cells to divide [1].
• The blood: Folate helps your body make healthy red blood cells. Without enough of it, you can develop megaloblastic anemia, where red blood cells are too large and too few [1].
• Healthy pregnancy: Getting enough folic acid before and during early pregnancy helps prevent major birth defects of the baby's brain and spine, called neural tube defects [1].
• The immune system: And the last one. Because immune cells multiply quickly when they're fighting an infection, they depend on folate, especially the T cells that coordinate your immune response [3] [4].

Why is folate important for the human body?

Without enough folate, you can develop megaloblastic anemia, which can cause weakness, fatigue, trouble concentrating, irritability, headaches, a racing heartbeat and shortness of breath. Low folate can also cause sores on the tongue and inside the mouth [1]. For women, not getting enough folate raises the risk of having a baby with a neural tube defect such as spina bifida [1].

The good news is that folate deficiency is rare in the United States. Since 1998, folic acid has been added to enriched bread, flour, pasta, rice and other grain products, and the number of babies born with neural tube defects has dropped [1]. Still, some groups are more likely to fall short, including teens, women ages 19 to 30, non-Hispanic Black women, people with alcohol use disorder, people with celiac or inflammatory bowel disease, and people with a gene variant called MTHFR [1].

Folate also connects to the two processes research links to declining health with age: increased oxidative stress, which is damage from excess free radicals, and chronic inflammation [5]. Along with vitamin B12 and vitamin B6, folate helps keep homocysteine in check, a compound that, along with oxidative stress and inflammation, has been linked to heart disease [6].

To be fair to the evidence, folic acid lowers homocysteine but doesn't directly lower heart disease risk, although some studies suggest folic acid combined with other B vitamins may help prevent stroke [1]. That's why research-based formulas include a full set of B vitamins above the RDA, rather than folate alone [7]. Folate does its best work as part of the team, not by itself.

How does folate support immune function?

Folate supports immune function by giving your immune cells what they need to multiply. When you're fighting an infection, immune cells divide quickly, and every new cell needs fresh DNA, which depends on folate [3] [4]. Low folate can lower your resistance to infections [3].

Think of your immune system as having two jobs: responding strongly when a threat shows up, and calming back down once the job is done. Let's look at how folate helps.

• First-line (innate) defense: This is your body's rapid-response team. The folate pathway helps natural killer cells stay active and multiply when they respond to germs [4].
• Targeted (adaptive) defense: This is the part of your immune system that learns and remembers specific threats. Cell-based immunity is especially sensitive to low folate. T cells respond less strongly, and the thymus, where T cells mature, can be affected [3].
• Making new cells fast: Because folate is needed for DNA, it's needed for any process that depends on rapid cell growth, and immune responses are one of the biggest [3] [4].

One honest note: most of this research looks at what happens when folate is low. It shows that getting enough folate helps your immune system work normally, not that extra folate boosts it beyond normal. And very high intakes of folic acid aren't recommended [1].

Getting the most from folate

If you want to get the most out of folate, here are five things the research points to.

• Know your form: The Micro Daily EMF formula uses L-5-methyltetrahydrofolate (L-5-MTHF), the active form of folate, providing 680 mcg DFE a day, 170% of the Daily Value [8]. Research shows L-5-MTHF is at least as effective as folic acid at raising folate levels, and it may be less likely to hide a vitamin B12 deficiency [2]. It may also suit people with the MTHFR C677T gene variant, whose bodies use it more easily [1].
• Could you become pregnant? Make sure you're getting folic acid: This is important. The NIH advises that all women and teen girls who could become pregnant get 400 mcg of folic acid a day, not 5-MTHF, even if they have an MTHFR variant [1]. That folic acid can come from fortified foods, a supplement or both. If this applies to you, talk with your healthcare provider about how your supplements fit.
• Stay under the upper limit: For adults, the upper limit for folate from supplements and fortified foods is 1,000 mcg a day. Folate from regular food doesn't count toward it [1].
• Don't take it alone: Folate works as a team with vitamin B12 and B6, and research-based formulations combine them with antioxidants and minerals [5] [7].
• Take your formula twice a day: Comprehensive formulas are designed to be split into a morning dose and an evening dose. Water-soluble B vitamins like folate are among the nutrients that leave the body quickly, which is the reasoning behind steadier dosing [9] [10].

One last thing to keep in mind: large amounts of folate from supplements can correct the anemia caused by low vitamin B12 while the nerve damage from low B12 keeps getting worse [1]. That's one more reason folate and B12 belong together, and why anyone with signs of low B12 should get checked.

Frequently asked questions about folate

How much folate do I need each day?

Teens and adults need 400 mcg DFE a day. During pregnancy that rises to 600 mcg DFE, and while breastfeeding to 500 mcg DFE. Children need 150 to 300 mcg DFE, depending on age [1]. On top of that, women and teen girls who could become pregnant should get 400 mcg of folic acid a day from fortified foods, supplements or both [1].

What's the difference between folate, folic acid and methylfolate?

Folate is the natural form in food. Folic acid is the manmade form used in fortified foods and most supplements, and your body has to convert it before using it. Methylfolate (5-MTHF) is the active form your body actually uses, and the main form in your blood [1] [2].

What foods are high in folate?

Beef liver, asparagus, Brussels sprouts and dark leafy greens such as spinach and mustard greens are rich natural sources. Oranges and orange juice, peanuts, black-eyed peas and kidney beans also provide folate. Folic acid is added to enriched bread, flour, pasta, rice and many breakfast cereals [1].

Who is most likely to be low in folate?

The groups most at risk are teens, women ages 19 to 30 and non-Hispanic Black women. People with alcohol use disorder, people with celiac or inflammatory bowel disease, and people with an MTHFR gene variant are also more likely to fall short [1].

What are the signs of low folate?

Low folate can cause megaloblastic anemia, which leads to weakness, fatigue, trouble concentrating, irritability, headaches, a racing heartbeat and shortness of breath. Some people also get sores in the mouth or changes in the color of their skin, hair or nails [1].

Can you take too much folate?

Folate from food isn't harmful. But it's best not to go over the upper limit of 1,000 mcg a day from supplements and fortified foods, unless your healthcare provider recommends it [1]. High doses can hide a vitamin B12 deficiency, and very high doses of folic acid might raise the risk of colorectal cancer in some people [1]. Folate can also interact with medications such as methotrexate and some seizure medicines, so check with your provider if you take them [1].

Explore more micronutrients

Folate works alongside other nutrients. Vitamin B12 partners with folate to make DNA and healthy red blood cells, and iron helps those cells carry oxygen. Learn more about vitamin D, magnesium, calcium, zinc and potassium.

Key sources: NIH Office of Dietary Supplements, Folate Fact Sheets for Health Professionals and Consumers [1]; Pietrzik K, Bailey L, Shane B, "Folic Acid and L-5-Methyltetrahydrofolate," Clinical Pharmacokinetics, 2010 [2]; Prasad KN, Micronutrients in Health and Disease, CRC Press, 2019 [5]. Every numbered citation links to its full entry on our References page.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease. Talk with your healthcare provider before starting any supplement, especially if you are pregnant, nursing, taking medication or have a medical condition.