Plasma and breast milk biotin concentrations decrease in lactating women consuming a dietary biotin intake exceeding current recommendations (827.10)

Abstract

Biotin is a water‐soluble B vitamin with many key roles in human metabolism. As a cofactor for several carboxylation reactions, biotin is required for gluconeogenesis, fatty acid synthesis, and leucine catabolism. Biotin may also interact with histones to affect genome expression. The dietary requirement for biotin is unknown. Thus, recommendations are provided as Adequate Intakes (AIs). The biotin AI for adults and pregnant women is 30μg/d and for lactating women, 35μg/d. As part of a controlled feeding study, healthy pregnant (n=26, 27wk gestation), lactating (n=28, 5wk postpartum), and control (non‐pregnant, non‐lactating; n=21) women consumed ~60μg dietary biotin/d for 10‐12 weeks. Plasma and breast milk samples were collected and biotin was measured at baseline (wk 0) and study end (wk 10 or 12). Plasma biotin was measured via ELISA kit and breast milk biotin was measured via LCMS. Throughout the study, the response of plasma biotin varied by reproductive group (P = 0.05). Among pregnant (P=0.65) and control (P=0.88) women, plasma biotin did not change from baseline (pregnant: 130ng/L (105, 161); control: 143ng/L (113, 180)) to study end (pregnant: 137ng/L (111, 170); control: 146ng/L (115, 184)). However, among lactating women, plasma biotin decreased (P < 0.01) from baseline (193ng/L (157, 237)) to study end (136ng/L (111, 167)) as did breast milk biotin concentrations (P = 0.02; baseline: 12pM/mL (8.2, 16.5); study end: 7pM/mL (4.8, 9.7)). In addition, plasma and breast milk biotin concentrations were correlated (rho=0.501; P< 0.001). These results indicate that plasma biotin may be a biomarker for breast milk biotin and that lactating women may benefit from a dietary biotin intake that exceeds the study dose of 60μg/d. Data presented as means and 95% confidence intervals.Grant Funding Source: Support:The Hartwell Foundation,The Gerber Foundation,NIH R03 HD065962‐01A1,Shepherd Univ Foundation