Urinary Excretion of 3‐Hydroxyisovaleryl Carnitine is Elevated in Lactating Women Consuming A Biotin Intake Exceeding Current Recommendations

Urinary excretion of 3‐hydroxyisovaleryl carnitine (3HIA‐carnitine) is a functional biomarker of biotin status as it reflects impairment in leucine catabolism caused by reduced activity of the biotin‐dependent enzyme 3‐methylcrotonyl‐CoA carboxylase. As part of a 12‐wk controlled feeding study, healthy non‐pregnant (n=12), pregnant (n=13, 27wk gestation) and lactating (n=12, 5wk postpartum) women consumed 56 mcg biotin per day (~ 2x current adequate intake [AI] levels) as measured by LCMS. Twenty four hour urine collections were obtained and 3HIA‐carnitine was measured at wk 0 and 12 via LCMS. By study end, lactating women excreted two times more 3HIA‐carnitine compared to baseline (p=0.005) and 8 of 12 lactating women were excreting 3HIA‐carnitine above the upper limit of normal (i.e. > 0.2 mmol/mol creatnine). Urinary 3HIA‐carnitine excretion did not change in response to 56 mcg biotin per day among pregnant and nonpregnant women. These results indicate that lactating women may benefit from a biotin intake that exceeds the current AI of 35 mcg per day. Measurements of additional static and functional biomarkers of biotin status are underway to provide a more comprehensive assessment of the impact of physiologic state (i.e., lactation) on biotin status and requirements. Funded and Supported by: The Gerber Foundation and The Hartwell Foundation.