vitamin
Folate vs Folic Acid: mcg DFE, Pregnancy and Limits
Also known as folic acid, vitamin B9, folacin, methylfolate, 5-MTHF, L-methylfolate, folate supplement
Short answer
Folate (vitamin B9) is a vitamin the body uses to make DNA and for cell division. Folic acid is the form in most supplements and fortified foods. Labels list mcg DFE: 400 mcg of folic acid is shown as 680 mcg DFE. The adult upper limit is 1,000 mcg a day of folic acid from supplements and fortified foods [1].
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What is Folate and Folic Acid?
Folate is a water-soluble B vitamin, also called vitamin B9 [1]. Folate is the general term for the folates in food and for the forms in supplements and fortified foods, including folic acid [1]. The body uses it as a coenzyme to make DNA and RNA and to process amino acids, which is needed for proper cell division [1]. It also helps the body form healthy red blood cells [2].
Forms of Folate and Folic Acid you'll see on labels
Food folate
The natural form in foods. About 50% is bioavailable [1].
Folic acid
The synthetic form used in fortified foods and most supplements. At least 85% is bioavailable with food, and nearly 100% on an empty stomach [1].
5-MTHF (methylfolate, L-methylfolate)
Found in some supplements. It is absorbed as well as or better than folic acid, but official conversion factors to mcg DFE have not been set; FDA allows labels to use a factor up to 1.7 [1].
How much Folate and Folic Acid do adults need?
NIH lists these Recommended Dietary Allowances (RDA) for adults 19+, in mcg DFE (dietary folate equivalents). Reference values, not a personal recommendation.
| Group | Amount per day |
|---|---|
| Men 19+ | 400 mcg DFE |
| Women 19+ | 400 mcg DFE |
| Pregnancy 19+ | 600 mcg DFE |
| Lactation 19+ | 500 mcg DFE |
Upper limit: 1,000 mcg a day for adults 19+ (including pregnancy and lactation) from supplements and fortified foods. This is in mcg, not mcg DFE: 1,000 mcg folic acid equals 1,667 mcg DFE. Folate in food is not counted, and the UL does not apply under medical supervision [1].
How Folate and Folic Acid appears on a label
Labels list folate in mcg DFE. If folic acid is added, the label must also show the folic acid amount in mcg in brackets [1]. Conversions: 1 mcg DFE = 1 mcg food folate = 0.6 mcg folic acid taken with food = 0.5 mcg folic acid on an empty stomach [1]. Supplements with 400 to 800 mcg folic acid are listed as 680 to 1,360 mcg DFE, because labels use mcg DFE = food folate + (1.7 x mcg folic acid) [1]. The Daily Value (DV) is 400 mcg DFE for adults and children 4 and older [1].
When to take Folate and Folic Acid
No official source names a best time of day to take folic acid. NIH notes that about 85% of folic acid is absorbed when taken with food and nearly 100% without food [1]. The NHS advises women who could get pregnant to start a daily 400 mcg folic acid supplement before pregnancy and continue until 12 weeks of pregnancy [2].
What to keep apart from Folate and Folic Acid
Vitamin B12
Large amounts of folate can correct the anemia of B12 deficiency but not the nerve damage, so high folic acid intakes might mask B12 deficiency [1]. The NHS says doses above 1 mg can mask B12 deficiency, a particular concern for older people [2].
Methotrexate
Methotrexate works against folate. People taking it for cancer should ask their oncologist before taking folate, as it could interfere with treatment [1]. Ask your pharmacist or doctor.
Antiepileptic medicines (phenytoin, carbamazepine, valproate)
These can lower folate levels, and folate supplements might lower blood levels of these medicines [1]. Ask your doctor before taking folate.
Sulfasalazine
It reduces folate absorption and can cause folate deficiency [1]. Ask your doctor whether you need more folate.
Alcohol
Alcohol interferes with folate absorption and increases its breakdown and loss in urine [1].
Foods that contain Folate and Folic Acid
- Beef liver
- Spinach
- Black-eyed peas
- Fortified breakfast cereals
- Enriched rice, pasta and bread
- Asparagus
- Brussels sprouts
- Romaine lettuce
- Avocado
- Broccoli
- Green peas and kidney beans
Who should ask a doctor or pharmacist first
Talk to a doctor if you are pregnant, planning a pregnancy or could get pregnant; some women are advised to take a higher dose, which should be discussed with a doctor first [2]. Ask a doctor or pharmacist first if you take methotrexate, antiepileptic medicines or sulfasalazine [1]. Older adults should ask about checking vitamin B12, since high folic acid doses can mask B12 deficiency [2].
Keep Folate and Folic Acid in a routine that fits
Supin schedules what you take by time of day, reminds you, and tells you when a bottle runs low.
Folate and Folic Acid: questions people ask
DFE means dietary folate equivalents. It adjusts for the fact that folic acid is absorbed better than food folate: 1 mcg DFE equals 1 mcg food folate, 0.6 mcg folic acid with food, or 0.5 mcg folic acid on an empty stomach [1].
No official source names a best time. About 85% of folic acid is absorbed with food and nearly 100% without food [1].
Sources
- Folate: Fact Sheet for Health Professionals — NIH Office of Dietary Supplements
- B vitamins and folic acid - Vitamins and minerals — NHS
Educational information, not medical advice. The amounts above are official reference values, not a recommendation for you. Check with your doctor or pharmacist before starting or changing supplements, especially if you take medication, are pregnant or have a health condition. Supin sells a subscription, not supplements. Last reviewed .