Folate

Vitamin B9 · Forms, food and label literacy

One vitamin family, more than one name.

Folate helps cells make the genetic material they need to grow and divide. It is a family of related vitamin B9 compounds, not a single name for every form. [3] Understanding that family makes a bowl of greens, enriched bread and a supplement label easier to compare.

FAMILY MAP · NOT A MOLECULAR STRUCTURE

Identity first

Folate is the umbrella; folic acid is one form.

Folate is the general name for the water-soluble vitamin B9 family. Food folates commonly occur as tetrahydrofolate derivatives with several attached glutamate units. Folic acid is a fully oxidized form with one glutamate unit, widely used in fortified foods and supplements. 5-MTHF, short for 5-methyltetrahydrofolate, is another form; supplement labels may call it methylfolate or L-methylfolate. [1]

A closer look: what does “one-carbon” mean?

The chemistry explains why these names deserve separate attention. Tetrahydrofolate, or THF, has a reduced ring system and is the parent of coenzymes that carry one-carbon units. “One-carbon” describes small chemical groups being transferred in metabolism, not a special kind of dietary carbohydrate. [2]

Inside the body

A helper in building and maintaining cells.

Folate coenzymes participate in making DNA and RNA and in amino-acid metabolism. [1] These are everyday cellular jobs, including in tissues such as skin. CDC describes folate's role in the production of new cells; that is a nutritional function, not evidence that a larger supplement dose makes skin renew faster. [3]

On the plate

Naturally present and deliberately added.

Food folate

Spinach, asparagus, Brussels sprouts, beans, peas and oranges are familiar food sources. A food contains a mixture of nutrients, rather than an isolated vitamin dose. [4]

Fortified folic acid

Folic acid is added to enriched grain foods such as certain breads, flours, pasta and rice, and to some breakfast cereals. Read the particular product's label rather than assuming every grain food is fortified. [4]

A label worth decoding

DFE is a comparison unit, not another ingredient.

Dietary folate equivalents, abbreviated DFE, account for differences in absorption between food folate and folic acid. The general US label Daily Value is 400 micrograms DFE. When folic acid is added, its amount appears in parentheses alongside the total folate amount. Those parentheses do not represent an extra amount to add to the total. [4]

A worked example

A label declaring 680 mcg DFE (400 mcg folic acid) supplies 170% DV, not 1,080 micrograms of folate. The folic acid is already included. This example uses the US label conversion of 1.7 for folic acid; it is label arithmetic, not a recommendation to take that serving. [1]

Original food research

Cooking method changes the result.

Could preparation change how much folate reaches the plate? McKillop and colleagues investigated that question in 2002 by comparing foods before and after cooking. Boiled spinach and broccoli retained about 49% and 44% of their raw folate concentrations. Steaming did not produce a significant decrease under the tested conditions. Whole potatoes behaved differently: their folate did not change significantly with boiling. [5]

The useful lesson is not that every cooked vegetable loses half its folate. A result belongs to a food and a preparation method. A mineral, vitamin or plant pigment can respond differently, so “raw versus cooked” is too broad a question for one universal winner.

How the researchers measured it

The team measured folate in food with a microbiological assay after extraction and enzyme treatment. Their comparison concerns food composition, not absorption in people. The steaming periods reached 4.5 minutes for spinach and 15 minutes for broccoli; the potato experiment tested boiling for 60 minutes. Those conditions help explain why the percentages should not be pasted onto every home-cooked serving.

Where form matters clinically

Pregnancy guidance names folic acid specifically.

CDC recommends 400 micrograms of folic acid daily for people who could become pregnant, alongside a balanced diet with folate-rich foods. Folic acid is the form shown to help prevent neural tube defects, which develop very early in pregnancy. A methylfolate label should not automatically be treated as evidence of the same prevention benefit. Discuss individual needs, medicines and any previous affected pregnancy with a clinician. [6]

At a glance

Reference box

Family: Folate · Vitamin B9 · Water-soluble vitamin.
Names to distinguish: Food folates · Folic acid · 5-MTHF / methylfolate.
Label unit: mcg DFE means micrograms of dietary folate equivalents.
Useful connection: Vitamin form, food preparation and declared serving all affect how to read the information.
Evidence lens: Cellular function, cooking retention and pregnancy-prevention evidence answer different questions.

Sources to follow

Revised October 25, 2026. Sources below distinguish chemical identity, food composition and the particular preparations or populations studied. Research methods and interpretation remain alongside the findings.

NIH Office of Dietary Supplements: Folate. Forms, coenzyme roles and DFE conversion.
ChEBI: Tetrahydrofolic acid. Reduced chemical form and one-carbon coenzyme identity.
CDC: About Folic Acid. Cellular roles and vitamin-family terminology.
FDA: Folate and folic acid on nutrition labels. Food sources, Daily Value and parenthetical amounts.
McKillop and colleagues, 2002. Original comparison of cooking methods and folate retention.
CDC: Folic Acid Sources and Recommended Intake. Current prevention guidance and form-specific evidence.