Final answer:
A supplement containing 150 mcg of folate provides 150 dietary folate equivalents (DFE). This calculation is based on the fact that synthetic folate in supplements is 100% bioavailable.
Step-by-step explanation:
The dietary folate equivalents (DFE) in a supplement containing 150 mcg of folate is 150 DFE. When calculating DFEs for food folate versus synthetic folate found in supplements and fortified foods, folate from dietary supplements is considered to be 100% bioavailable, thus 1 mcg of synthetic folate is equivalent to 1 DFE. Therefore, if a supplement contains 150 mcg of folate, it provides 150 DFE.
The Food and Nutrition Board of the Institute of Medicine recommends that all people who might become pregnant consume at least 400 mcg/day of folate from supplements or fortified foods to help reduce the risk of neural tube defects in the developing fetus.