Following a request from the European Commission, the EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) was asked to deliver a scientific opinion on Dietary Reference Values (DRVs) for the European population, including biotin.
In 1993, the Scientific Committee for Food proposed an Acceptable Range of Intakes of biotin for adults of 15–100 µg/day, based on observed intakes of biotin in European countries, which were considered adequate to meet requirements and prevent deficiency.
Biotin is a water-soluble vitamin which serves as a co-factor for several carboxylases that play critical roles in the synthesis of fatty acids, the catabolism of branched-chain amino acids and gluconeogenesis. Dietary biotin deficiency is rare.
Free biotin is absorbed nearly completely, while there is a lack of data on the absorption of protein-bound biotin from foods. In the cell, biotin is covalently attached to biotin-dependent carboxylases, from which it can be released by other enzymes, or, alternatively, is catabolised through different pathways. Biotin and its metabolites are excreted in the urine.
The Panel notes that biomarkers sensitive to biotin depletion have been identified. These include urinary biotin excretion and biomarkers of biotin function, such as urinary excretion of 3-hydroxyisovaleric acid (3HIA) and 3HIA-carnitine, activity of propionyl-CoA carboxylase and abundance of biotinylated β-methylcrotonyl-CoA carboxylase and propionyl-CoA carboxylase in lymphocytes. However, data from the general population are limited so that the variability characteristics of these biomarkers and their ability to discriminate between biotin insufficiency and adequacy are not well known. Dose-response relationships between biotin intakes and these biomarkers have not been established. The Panel considers that data are insufficient to derive an Average Requirement (AR) for biotin from the use of available biomarkers of intake or status for any population group.
Data available on biotin intakes and health consequences are very limited and cannot be used to derive DRVs for biotin.
As the evidence to derive an AR, and thus a Population Reference Intake is considered insufficient, an Adequate Intake (AI) is proposed for all population groups. There is no indication that the AI should differ according to sex. The setting of AIs is based on observed biotin intakes with a mixed diet and the apparent absence of signs of deficiency in the EU, suggesting that current intake levels are adequate. Estimates of the biotin content of foods vary widely partly as a result of natural variation and partly depending on the analytical method used, and this contributes to uncertainty regarding current intake estimates. Estimates of biotin intakes in children, adolescents, adults and older adults were available from five EU countries. In boys and girls (5–12 years), mean/median intakes ranged from 19 to 38 µg/day, while mean/median intakes between 17 and 64 µg/day were reported for adolescent boys and girls (13–19 years). In adult men and women below about 65 years, mean/median intakes ranged from 26 to 50 µg/day, while mean/median intakes between 24 and 43 µg/day were reported for older adult men and women.
The AI for adults is set at 40 µg/day. The AI for adults also applies to pregnant women. For lactating women, an additional 5 µg/day over and above the AI for adults is proposed, to compensate for biotin losses through breast milk. For infants over six months, an AI of 6 µg/day is proposed by extrapolating from the biotin intake of exclusively breastfed infants aged zero to six months, using allometric scaling (body weight to the power of 0.75) and reference body weight for each age group, in order to account for the role of biotin in energy metabolism, and rounding to the nearest unit. The AIs for children aged 1–3 and 4–10 years are set at 20 and 25 µg/day, respectively, and for adolescents at 35 µg/day, based on observed intakes in the EU.