Folate: what it does, how much you need, and how much is too much
By Vita · fact-checked against NIH ODS
Vita is Vitaminico's AI nutrition coach. Every number here is checked against the NIH Office of Dietary Supplements; these pages have not yet been reviewed by our registered dietitians.
A B vitamin (B9) your body uses to build DNA and make healthy new cells.
Folate: key facts
- Everyday need (RDA/AI)
- 400 mcg DFE for all adults; 600 mcg DFE in pregnancy, 500 mcg DFE in lactation
- Safe upper limit (UL)
- 1,000 mcg (synthetic folic acid only)
- Measured in
- mcg
- Best foods
- Beef liver, spinach and dark leafy greens, asparagus, Brussels sprouts, beans and lentils, fortified grains
Adult values from the NIH ODS Folate fact sheet. Needs differ in pregnancy, lactation and childhood.
What does folate do?
Folate is a water-soluble B vitamin (also called vitamin B9) that acts as a helper in making and repairing DNA and RNA and in processing amino acids. It's essential for producing healthy new cells, which is why needs rise during rapid growth like pregnancy and infancy. It also helps convert homocysteine into methionine, and without enough folate, cells can't divide properly, leading to a form of anemia. "Folate" is the form found naturally in food; "folic acid" is the synthetic form added to fortified foods and most supplements.
Why you might be low on folate
- Heavy or regular alcohol use, which worsens diet quality and blocks folate absorption, uptake, and storage while speeding its breakdown
- Pregnancy or being of childbearing age, when needs jump (600 mcg DFE/day in pregnancy vs 400 for other adults) and are hard to hit by diet alone
- Malabsorptive conditions like celiac disease, inflammatory bowel disease, or tropical sprue that reduce how much folate you absorb
- Reduced stomach acid from atrophic gastritis, gastric surgery, or certain medications, which lowers folate absorption
- An MTHFR (677C>T) gene variant that reduces your ability to convert folate to its active 5-MTHF form
- A diet low in vegetables, fruit, beans, and fortified grains
Signs of low folate
These are common signals, not a diagnosis — a blood test and your clinician confirm a real gap.
- Megaloblastic anemia (large, immature red blood cells) causing weakness, fatigue, and shortness of breath
- Trouble concentrating, irritability, and headache
- Heart palpitations
- Soreness or shallow ulcers (sores) on the tongue and inside the mouth
- Changes in the color of skin, hair, or fingernails
- During pregnancy, a higher risk of neural tube birth defects, low birth weight, or preterm delivery
Best food sources of folate
| Food | Typical amount |
|---|---|
| Beef liver, braised | 215 mcg DFE per 3 oz (54% DV) |
| Spinach, boiled | 131 mcg DFE per 1/2 cup (33% DV) |
| Black-eyed peas (cowpeas), boiled | 105 mcg DFE per 1/2 cup (26% DV) |
| Fortified breakfast cereal (at 25% DV) | 100 mcg DFE per serving (25% DV) |
| Asparagus, boiled | 89 mcg DFE per 4 spears (22% DV) |
| Avocado, raw, sliced | 59 mcg DFE per 1/2 cup (15% DV) |
| Orange juice | 35 mcg DFE per 3/4 cup (9% DV) |
How much folate is too much?
The tolerable upper intake level (UL) for adults is 1,000 mcg (synthetic folic acid only) per day. The 1,000 mcg UL applies only to synthetic folic acid from supplements/fortified foods, not natural food folate; adequate folic acid before and early in pregnancy prevents neural tube defects.
There's no upper limit for folate from food, but the limit for folic acid from supplements and fortified foods is 1,000 mcg/day for adults. High folic acid intake can correct the anemia of a vitamin B12 deficiency while letting its nerve damage silently progress, so it can mask a serious B12 problem until it's harder to reverse.
Stacking a multivitamin, a single supplement and fortified foods adds up faster than it looks — run your full dose through the free Supplement Safety Checker before adding anything new.
Folate FAQ
What's the difference between folate and folic acid?
Folate is the form found naturally in foods like leafy greens and beans; folic acid is the synthetic form added to fortified grains and most supplements. Folic acid is better absorbed (about 85% vs roughly 50% for food folate), which is why intakes are measured in "dietary folate equivalents" (DFE).
Why is folate so important before and during pregnancy?
Adequate folate before conception and in early pregnancy lowers the risk of neural tube defects. Health authorities advise anyone who could become pregnant to get 400 mcg/day of folic acid from supplements or fortified foods, on top of folate from a varied diet; the pregnancy RDA is 600 mcg DFE/day.
Can taking too much folic acid hide a vitamin B12 deficiency?
Yes. Large amounts of folic acid can fix the anemia caused by low B12 without stopping B12-related nerve damage, so a deficiency can go unnoticed. This is why the daily upper limit for folic acid is set at 1,000 mcg for adults.
Source
Every RDA/AI, upper limit and unit on this page is drawn from the NIH Office of Dietary Supplements Folate fact sheet ›.
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Educational, not medical advice. The upper limits shown are Tolerable Upper Intake Levels for healthy adults from all sources combined; needs differ in pregnancy, lactation, childhood and with some conditions or medications. This page does not diagnose a deficiency or set your dose — talk to your clinician before starting any high-dose supplement.