In the absence of data on biotin deficiencies in normal individuals, a reasonable inference would be that the average current dietary intake of biotin should meet the dietary requirement. With this approach, the AI for biotin might be set at either 40 or 60 µg/day depending on the data set used (see “Dietary Intake”). Extrapolation from the AI for infants exclusively fed human milk would be expected to overestimate the requirement for adults because adults require biotin only for maintenance. The result of such an extrapolation using the formula

is 30 µg/day of biotin. Based on this very limited evidence, the AI for adults is set at 30 µg/day of biotin. This value should be adequate for maintaining normal excretion of 3-hydroxyisovaleric acid in adults (NI Mock et al., 1997). Data are not sufficient to set separate values for men and women or for the elderly.

Two recent studies (Mock and Stadler, 1997; DM Mock et al., 1997b) have raised questions, previously expressed (NRC, 1989), about the adequacy of biotin status during pregnancy. Some studies