Dietary Folate Equivalents (DFE) are the standardized unit used on nutrition labels in the U.S. to account for the differing bioavailabilities of natural food folate and synthetic folic acid. A milligram (mg) is a larger unit than a microgram (mcg), with 1 milligram equal to 1,000 micrograms. To determine how much folate is 1.7 mg DFE, the first step is to convert the milligrams to micrograms. Thus, 1.7 mg DFE is equal to 1,700 mcg DFE.
Converting 1.7 mg DFE to Micrograms of Folate
To convert 1.7 mg DFE to micrograms, we must first recognize that a milligram is one thousand times larger than a microgram. The conversion is straightforward:
- 1.7 mg x 1,000 = 1,700 mcg
Therefore, 1.7 mg DFE is 1,700 mcg DFE. This value, however, represents the equivalent and not necessarily the actual amount of pure folate or folic acid, as DFE is a composite measure.
Deconstructing Dietary Folate Equivalents (DFE)
To fully understand what 1,700 mcg DFE means, we need to know the conversion factors for different folate forms. The bioavailability of folate depends on its source—natural food folate, or synthetic folic acid found in fortified foods and supplements.
- Food Folate: The body absorbs natural folate from foods like spinach, lentils, and avocados. 1 mcg of food folate is equivalent to 1 mcg DFE.
- Folic Acid from Fortified Foods/Supplements with food: Folic acid is more readily absorbed. 1 mcg of folic acid is equivalent to 1.7 mcg DFE.
- Folic Acid from Supplements (empty stomach): When taken without food, folic acid absorption is even higher. 1 mcg of folic acid is equivalent to 2 mcg DFE.
Since 1.7 mg DFE is a measure on a nutrition label, it most likely represents the total dietary intake from a combination of sources. The label itself must break down the source if folic acid has been added to the product.
Example Scenarios for 1.7 mg DFE
Consider the different compositions that could result in 1.7 mg DFE (1,700 mcg DFE).
- Scenario 1: Purely Food Folate
- If the source was only natural food folate, the product would contain 1,700 mcg of food folate.
- Scenario 2: Only Fortified Folic Acid
- If the source was only synthetic folic acid in a fortified food, the conversion would be: 1,700 mcg DFE / 1.7 = 1,000 mcg (or 1 mg) of folic acid.
- Scenario 3: A Combination of Sources
- A product might contain a mix of natural food folate and fortified folic acid, where the label combines them into a total DFE figure. For instance, 100 mcg of food folate and 941 mcg of folic acid from a fortified source would sum to 1,700 mcg DFE (100 + (941 * 1.7) = 100 + 1,599.7 = 1,699.7, which rounds to 1,700).
Why DFE Is Important for Supplementation
For those taking supplements, DFE is a crucial measure for safety, especially regarding upper intake levels. The Tolerable Upper Intake Level (UL) for folic acid from fortified foods and supplements is 1,000 mcg per day for adults. Exceeding this can mask a vitamin B12 deficiency, a condition that can cause neurological damage. A supplement providing 1.7 mg DFE (1,700 mcg DFE) could contain 1,000 mcg of folic acid if consumed with food (1,000 mcg * 1.7 = 1,700 mcg DFE), exactly at the UL. However, if taken on an empty stomach, the 1,700 mcg DFE might correspond to an even lower amount of folic acid (1,700 mcg DFE / 2.0 = 850 mcg folic acid), demonstrating the complexity.
Understanding DFE for Pregnant Women
For pregnant women, adequate folate is essential to prevent neural tube defects. The Recommended Dietary Allowance (RDA) for pregnant women is 600 mcg DFE per day. A supplement with 1.7 mg DFE (1,700 mcg DFE) significantly exceeds this RDA, which is often recommended for maximum protection against neural tube defects. It is important to consult a healthcare provider to ensure appropriate supplementation. The DFE calculation helps professionals manage and interpret total folate intake accurately.
Comparison of Folate Forms
| Feature | Food Folate | Folic Acid (Fortified Foods/Supplements with Food) | Folic Acid (Supplements on Empty Stomach) |
|---|---|---|---|
| Bioavailability | ~50% | ~85% | ~100% |
| Conversion to DFE | 1 mcg = 1 mcg DFE | 1 mcg = 1.7 mcg DFE | 1 mcg = 2.0 mcg DFE |
| Chemical Form | Naturally occurring, complex | Synthetic, simple | Synthetic, simple |
| Source | Green vegetables, legumes, fruits | Fortified cereals, bread, pasta | Vitamin supplements |
| Absorption Rate | Slower | Faster | Very fast |
Conclusion
In summary, 1.7 mg DFE is equivalent to 1,700 mcg DFE. This value does not tell you the pure amount of folate or folic acid without knowing the source. It is a standardized measure that accounts for the different absorption rates of naturally occurring folate and synthetic folic acid. For dietary labels, 1.7 mg DFE often represents a significant amount, especially when considering the Tolerable Upper Intake Level for folic acid. Understanding these conversions is key to accurately interpreting nutrition information and ensuring safe, effective supplementation.
