Vitamin B11 or B9? Here's the scoop on folate and folic acid

Folate is an essential vitamin for DNA synthesis, cell division, and blood formation. In this blog, you’ll learn why the same vitamin is also called B9 or B11, what the difference is between folate and folic acid, and when serum or erythrocyte folate is the best test.

One bottle says vitamin B11, another says B9. And then there’s also folate and folic acid. It sounds like four different substances, but they’re all referring to the same vitamin. In this blog, you’ll learn where those names come from, what the difference is between folate and folic acid, and which blood test provides the most information.

Vitamins B9 and B11 are the same vitamin

Outside the Netherlands, folate is almost always called vitamin B9. That’s the name used by scientists, the European Food Safety Authority (EFSA), and laboratories around the world. In the Netherlands and Belgium, you’ll still often see “vitamin B11.” That’s an older term that has stuck on many product packages and websites. So whether you see B9 or B11, they refer to the same thing.

What is the difference between folate and folic acid?

Folate is found in your food

Folate is the form that occurs naturally in food. You get it mainly from green vegetables such as spinach, kale, broccoli, and asparagus. Legumes, avocados, oranges, and liver are also good sources. Folate is sensitive to heat. If you cook vegetables for too long, some of it is lost. That’s why briefly steaming or stir-frying them is a good idea.

Your body absorbs folate from food less efficiently than it does folic acid. On average, about half of it ends up in your blood.

Folic acid is found in supplements

Folic acid is the synthetic form. You’ll find it in multivitamins, standalone supplements, and some breakfast cereals. Your body absorbs it well, but it must first be converted before your cells can use it.

What is 5-MTHF or active folate?

In your body, folate and folic acid are converted in a few steps into 5-methyltetrahydrofolate, or 5-MTHF for short. That’s the form your cells actually use. That’s why it’s also called active folate. You can also buy it as a supplement.

What does vitamin B11 do in your body?

Your body produces new cells all day long. Every time a cell divides, your DNA must be copied, and that requires folate. In addition, folate helps produce red blood cells, metabolize homocysteine, and support the normal functioning of your immune system.

Your body cannot produce folate on its own. This means you rely on what you eat and, if necessary, on a supplement. Tissues that regenerate quickly, such as your bone marrow and intestinal lining, are the first to show signs of a deficiency.

Folate and Anemia

If you have a folate deficiency for an extended period, your bone marrow will produce red blood cells that are too large and don’t function as well. This is called megaloblastic anemia, a type of anemia. Symptoms include fatigue, pale skin, getting out of breath more easily, or dizziness. These symptoms usually don’t appear until the deficiency has been present for some time.

Folic acid when trying to conceive—and afterward?

Almost everyone is familiar with this advice: If you’re trying to get pregnant, take 400 micrograms of folic acid daily. Start taking it at least four weeks before conception and continue through the tenth week of your pregnancy. This reduces the risk of a neural tube defect in your baby, such as spina bifida. This advice also applies if you have an MTHFR variant.

After pregnancy, folic acid often falls by the wayside. Yet everyone needs folate, including men and older adults. For adults, the recommended daily intake is 300 micrograms of folate equivalents. If you eat enough vegetables every day and legumes from time to time, you’ll usually meet that requirement.

Folate, methylation, and homocysteine

Folate is necessary for methylation. During this process, your body passes on small building blocks that it uses, among other things, to produce DNA and to convert homocysteine into methionine. If this process isn’t working properly, your homocysteine levels may rise.

However, high homocysteine levels alone do not automatically mean you have a folate deficiency. A deficiency in vitamin B12 or B6 could also be the cause, as could kidney function, smoking, drinking a lot of coffee, or certain medications. That’s why you always need to look at the big picture.

How do you develop a folic acid deficiency?

Eating few vegetables is the most well-known cause, but not the only one. A deficiency can also occur if your body absorbs folate less efficiently or actually needs more of it. For example:

• drinking a lot of alcohol
• intestinal diseases such as celiac disease or Crohn’s disease
• surgery on your intestines
• Pregnancy and Breastfeeding
• medications such as methotrexate and certain anti-epileptic drugs

Symptoms of a Vitamin B11 Deficiency

You often don’t notice a mild deficiency. If the deficiency worsens, you may experience fatigue, shortness of breath during exertion, a painful red tongue, or sores in the corners of your mouth. Such symptoms can also have many other causes. A folic acid blood test will show whether folate is a factor.

Getting your folate levels tested: serum or red blood cells?

There are two ways to measure folate in your blood. Each one looks at something different.

Serum folate: your recent intake

Serum folate measures how much folate is currently in your blood. This is the standard test and usually the first choice if you want to know whether you have a deficiency. However, the result reacts quickly to what you’ve eaten or taken in the past few days. If you’ve just started taking a supplement, the result may already be within the normal range even though your stores haven’t been replenished yet.

Erythrocyte Folate: Your Supply Over Several Months

Erythrocyte folate, also known as intracellular folate, measures the folate in your red blood cells. These cells absorb folate as they are produced and live for about 120 days. As a result, the results reflect the past three to four months rather than what you ate yesterday. However, a vitamin B12 deficiency can affect this value.

Serum folate gives you information about your current status, while erythrocyte folate reflects your status over the past few months. Together, they provide a more complete picture. Because folate and vitamin B12 work closely together, it’s a good idea to have your B12 levels tested as well. If you have any symptoms or are unsure about your results, discuss them with your primary care physician.

MTHFR and folic acid: What does a gene variant mean?

The MTHFR gene contains the code for an enzyme that converts folate to 5-MTHF. Many people have a variant of this gene, such as C677T or A1298C. If you have two copies of the C677T variant, the enzyme does not function as well.

That sounds more dramatic than it usually is. Most people with this variant have normal folate levels and no symptoms. A genetic variant is not a diagnosis. What matters is what your blood levels look like—such as folate, homocysteine, and vitamin B12.

Should you take folic acid or active folate?

Supplements containing 5-MTHF are often recommended for people with an MTHFR variant. That’s an option, but you don’t have to avoid folic acid. Even with a variant, your body still metabolizes folic acid. If you’re trying to conceive, folic acid remains the official recommendation, because research on the prevention of neural tube defects is based on that.

If you take a lot of folic acid, some of it may remain unchanged in your blood. Researchers are still investigating what this means for your health.

How much folic acid do you need each day?

Many supplements contain 800 to 1,000 micrograms of folic acid. That is well above the 300 micrograms an adult needs per day. The EFSA considers 1,000 micrograms of folic acid per day to be a safe upper limit for adults.

There’s another reason not to just take a lot of extra folic acid. It can mask anemia caused by a vitamin B12 deficiency, while the B12 deficiency itself continues unabated. If you’re taking a high dose, be sure to also have your active vitamin B12 levels tested. If your doctor has prescribed a high dose, simply continue taking it as directed.

Frequently Asked Questions About Vitamin B11

Is vitamin B11 the same as folic acid?

Almost. Vitamin B11 is the name of the vitamin. Folic acid is the synthetic form found in supplements, while folate is the natural form found in food.

Is vitamin B9 the same as vitamin B11?

Yes. B9 is the international name; B11 is the older name that you still often see in the Netherlands and Belgium.

Which foods are high in folate?

Green leafy vegetables such as spinach and kale, broccoli, asparagus, legumes, avocado, oranges, and liver.

How much folic acid do you need each day?

Adults need 300 micrograms of folate equivalents per day. If you’re trying to get pregnant, the recommendation is an additional 400 micrograms of folic acid per day, starting four weeks before conception and continuing through the tenth week of your pregnancy.

What is the difference between serum folate and erythrocyte folate?

Serum folate shows how much folate is currently in your blood. Erythrocyte folate provides more insight into your folate status over the past three to four months.

Is folate only important if you’re trying to get pregnant?

No. Everyone needs folate, among other things for cell division, the production of red blood cells, and your immune system.

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