Nutrient Unit Conversion Calculations

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Nutrient Unit Conversion Calculations

Editor’s note: this post was originally published on September 19, 2016, and has been updated for accuracy and comprehensiveness.

With the release of the new rules for Nutrition Facts Labels, some of the nutrient measurement units have been revised. This blog covers those revisions and gives you the formulas for calculating the changes. A list of the calculations only can be found on this cheat sheet.

Vitamin D

Vitamin D was a voluntary nutrient shown on the label in IUs, but is now a mandatory nutrient listed in mcg. (Vitamin D IUs may be listed voluntarily in parenthesis as well.) So, to find the number of mcg, you need to multiply your total number of IUs by 0.025.

  • Calculation: Vitamin D mcg = Vitamin D IU x 0.025

Vitamin A

Vitamin A was a mandatory nutrient and is now a voluntary label nutrient. If Vitamin A is listed on the new nutrition label it must be listed in mcg of Retinol Activity Equivalents (RAE), which is a change in unit from the pre-existing label, where Vitamin A was listed in IUs.

The conversion from IUs to mcg RAE considers whether Vitamin A is coming from an animal source (retinol) or a plant source (carotenoids), or a combination of sources. We have calculated this conversion for foods in the ESHA database where possible.

For foods that you enter yourself, you can determine the Vitamin A mcg RAE value by converting from IUs using these formulas:

Animal source: pre-formed retinol

  • Calculation: Vitamin A mcg RAE = Vitamin A IU x 0.3

Plant source: beta-carotene from food

  • Calculation: Vitamin A mcg RAE = Vitamin A IU x 0.05

Plant source: beta-carotene from supplements

  • Calculation: Vitamin A mcg RAE = Vitamin A IU x 0.3

Plant source: alpha-carotene or beta-cryptoxanthin from food

  • Calculation: Vitamin A mcg RAE = Vitamin A IU x 0.025

When working with ingredients where Vitamin A comes from a combination of animal and plant sources, you may need to contact your suppliers for more detail. This is also the case with Vitamin E and Folate.


Vitamin E

Vitamin E is a voluntary nutrient whose label unit has changed from IU to mg of alpha-tocopherol. The conversion factor you use depends on whether the source is natural or synthetic.

Natural source: food

  • Calculation: Vitamin E alpha-tocopherol mg = Vitamin E IU x 0.67

Synthetic source: supplement

  • Calculation: Vitamin E alpha-tocopherol mg = Vitamin E IU x 0.45

Niacin

Niacin is a voluntary nutrient whose label unit has changed from mg of Niacin to mg of Niacin Equivalents (NE). Niacin Equivalents include niacin converted from the amino acid tryptophan.

From Niacin

  • Calculation: Niacin mg NE = Niacin mg (The units are equivalent.)

From the amino acid tryptophan

  • Calculation: Niacin mg NE = Tryptophan mg / 60


Folate

Folate is a voluntary nutrient whose label unit has changed from mcg to mcg DFE (Dietary Folate Equivalents). The conversion factor depends on the source of folate.

Natural source: food

  • Unit conversion: 1 mcg DFE = 1 mcg Folate from food
  • Calculation: Folate mcg DFE = Food Folate mcg (The units are equivalent.)

Synthetic source: supplement

  • Calculation: Folate mcg DFE = Folic Acid mcg x 1.7

Dietary Fiber

The final rule incorporates two major changes to the dietary fiber declaration—a definition of “dietary fiber,” a term that FDA had not previously defined, and an increase in the DRV from 25 grams to 28 grams. The new definition focuses on reporting fiber that is considered beneficial to human health. To learn more about this topic check out our Dietary Fiber Blog Series.

Beneficial fiber

  • Calculation: 1 gm Total Dietary Fiber = 1 gm Dietary Fiber (The units are equivalent.)

Not beneficial fiber

  • Calculation: 1 gm Total Dietary Fiber = 0 gm Dietary Fiber
    (If the non-digestible carbohydrates do not meet the FDA definition for Dietary Fiber, these cannot be listed as fiber on the 2016 label.)