Why is it so hard to find the amount of biotin in food? According to the WHO publications biotin is a thing we need. Although its non toxic, so you can't get too much. However, excluding a few (small) lists that deal exclusively with biotin content there doesn't generally seem to be any information on how much of it given foods contain. For instance this page gives a very impressive summary of a kiwi, but there is no mention of biotin. If this is something we need, why is it not normally listed?

Apparently, it's really hard to measure biotin levels in food accurately.

From "Determination of the biotin content of select foods using accurate and sensitive HPLC/avidin binding" (2004, emphasis added):

> Total biotin content of 87 foods was determined using acid hydrolysis and the HPLC/avidin-binding assay. These values are consistent with published values in that meat, fish, poultry, egg, dairy, and some vegetables are relatively rich sources of biotin. However, these biotin values disagreed substantially with published values for many foods. Assay values varied between 247 times greater than published values for a given food to as much as 36% less than the published biotin value. Among 51 foods assayed for which published values were available, only seven agreed within analytical variability (720%). **We conclude that published values for biotin content of foods are likely to be inaccurate.**