The present invention relates to an assay for determining the levels of sterols, stanols, steryl esters, fatty acid derivatives and combinations thereof in a starch-containing food product. The assay is particularly useful in supporting product health and/or nutritional claims in manufacturing products intended for human or animal consumption. The present invention describes a method for extracting sterols related compounds and uses as an internal standard a steryl ester, preferably cholesterol oleate. By using the present extraction technique the process enables the recovery of substantially all of the sterol related compound in the sample.