Vitamin Conversions

RAE. Ever heard of it? It’s a “retinol activity equivalent” and it’s the new way we talk about vitamin A. Basically vitamin A is important because it’s a source of a molecule called “retinol.” This is the active ingredient that your eye uses to process light. Converting vitamin A from IUs into the new “RAE” unit is easy. We are just converting the IU into “micrograms” or “mcg.” All you need to do is take the IU and multiply by 0.3 and you will get the mcg RAE. For example:

3000 IU vitamin A * 0.3 = 900 mcg RAE vitamin A

To go the other way just divide:

900 mcg RAE vitamin A / 0.3 = 3000 IU vitamin A

Most people are used to talking about vitamin D in IU, and that’s not a bad thing. Actually FDA still allows the use of the IU in parentheses on the supplement facts panel. However, not every company is going to do that, so here is how you calculate. Just take the IU and divide it by 40. For example:

800 IU vitamin D / 40 = 20 IU vitamin D

To go the other way, just multiply:

20 mcg vitamin D * 40 = 800 IU vitamin D

Vitamin E is a little more complicated than the other vitamins to go from IU to mg. However, as long as you know whether you are dealing with synthetically-derived or naturally-sourced vitamin E it’s quite easy.

The most common form of vitamin E is the “dl-alpha tocopherol” form. If you see this form, you just multiply the IU by 0.45. For example:

400 IU of vitamin E as dl-alpha * 0.45 = 180 mg vitamin E

To go the other way you just divide:

180 mg vitamin E at dl-alpha / 0.45 = 400 IU vitamin E

If it’s a naturally-sourced vitamin E, you will see it called “d-alpha.” If you see “d-alpha” on the label, just multiply the IU by 0.67. For example:

400 IU of vitamin E as d-alpha * 0.67 = 268 mg vitamin E

To go the other way you just divide:

268 mg vitamin E as d-alpha / 0.67 = 400 IU vitamin E

What’s a DFE you might ask? It’s a “dietary folate equivalent.” This is a unit of measure that’s been developed to better equate the biological effects of the folate found in food compared to the synthetic sources of folate such as folic acid and methylfolate. Synthetic sources are more potent at increasing the folate levels in your body compared to food sources. So the amount of DFE provided by these sources is higher.

The conversion is really easy. Just divide the amount of mcg folic acid by 0.6 and you will see the amount of folate mcg DFE you have. For example:

400 mcg folic acid / 0.6 = 667 mcg DFE folate

To go the other way just multiply:

667 mcg DFE folate * 0.6 = 400 mcg folic acid