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Folate (B9): the daily reference intake

Folate carries the single most important preventive recommendation in nutrition: 400 micrograms of folic acid a day, from before conception through the first twelve weeks, cuts the risk of neural tube defects. The general adult reference intake is 330 micrograms of dietary folate equivalents, rising to 600 in pregnancy.

These are published population reference values, not a diagnosis and not a prescription. A reference intake describes what covers a healthy group; it cannot tell you your own status, and no page can. Pregnancy, chronic illness, medicines and malabsorption all change the picture — take those questions to a doctor, midwife, pharmacist or dietitian.

Folate (B9) by age, sex and life stage

EFSA values are in micrograms of dietary folate equivalents. One DFE is 1 microgram of natural food folate, or 0.6 micrograms of folic acid taken with food, because synthetic folic acid is absorbed far more efficiently.

The 400 microgram recommendation, and why timing is everything

The neural tube closes in the fourth week after conception, before most pregnancies are recognised. That single fact drives the whole recommendation: a supplement started after a positive test is largely too late for this particular purpose. National authorities across Europe therefore advise 400 micrograms of folic acid a day for any woman who could become pregnant, from before conception through the first twelve weeks.

This is a supplement recommendation, not a dietary one, and it is deliberate. Reaching the same level reliably from food alone is difficult, and the evidence base — from trials and from countries that fortify flour — is built on folic acid. A higher dose is sometimes prescribed where the risk is higher, for example after a previously affected pregnancy or with certain medicines, and that is a clinical decision.

Dietary folate equivalents, and why the food table reads low

Natural food folate is absorbed at roughly half the efficiency of synthetic folic acid, so the two cannot be added directly. The DFE unit handles that: 1 microgram of DFE is 1 microgram of food folate, or about 0.6 micrograms of folic acid taken with food.

The USDA composition data used for the food table below reports food folate in micrograms, not DFE. Since the EFSA target is written in DFE and food folate converts one to one, the food column is directly comparable for natural sources — but any fortified product would need converting, and none are ranked here.

Folate and B12 are entangled

Both vitamins are needed for the same step in DNA synthesis, and a deficiency of either produces the same large-cell anaemia. Folic acid supplementation can correct that anaemia even when the real problem is vitamin B12, while the B12-related nerve damage continues unchecked. That is the specific reason folic acid has an upper level at all, and the reason B12 status is worth knowing before taking high-dose folic acid — particularly in older adults, where B12 absorption often falls.

Where it comes from

The name comes from folium, leaf. Dark green leafy vegetables, broccoli, Brussels sprouts, legumes — lentils and chickpeas are outstanding — beetroot, oranges, wholegrain, nuts and seeds. Liver is extremely high. Folate is heat-sensitive and leaches into cooking water, so long boiling costs a substantial share of it.

The upper level

The tolerable upper intake level of 1 000 micrograms a day applies to FOLIC ACID from supplements and fortified foods, not to folate naturally present in food. The concern is that high folic acid intake can mask the anaemia of vitamin B12 deficiency while the neurological damage continues, which is why B12 status matters before taking large folic acid doses.

Ordinary food against the 330 microgram adult reference intake

Top of this list: Lentils, 326 µg food folate in a 180 g serving (a portion, cooked) — 99% of the 330 microgram adult reference intake. It would take about 2 of those to cover a full day from that one food, which is why a real diet spreads it across several rows.

Unit: The reference value is in dietary folate equivalents (DFE); the composition data is natural food folate, which converts to DFE one for one. Fortified products, where folic acid is absorbed about twice as efficiently, would need converting - none are ranked here.

Portion sizes are ordinary household servings chosen for this table, not official reference portions, and the shortlist is an editorial one: everyday foods eaten in this region rather than the highest per-100 g entries in the database. A raw per-100 g ranking would be topped by dried herbs, drink powders and fortified breakfast cereals, which answers a different question. The composition data is American, so where US fortification practice differs from European practice the row carries a dagger and the reason. For the full per-100 g ranking of a nutrient, the food-data section of this site publishes one.

Folate (B9) for one group at a time

Sources: EFSA Dietary Reference Values · Regulation (EU) No 1169/2011, Annex XIII · USDA FoodData Central SR Legacy (food composition) · EFSA scientific opinion on dietary reference values for folate (2014) · World Health Organization guidance on periconceptional folic acid supplementation · checked 2026-09-06

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