Scientific opinion on dietary reference values for thiamin

Following a request from the European Commission, the EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) derived dietary reference values (DRVs) for thiamin (vitamin B1). The Panel considers that data from depletion\u2013repletion studies in adults on the amount of dietary thiamin intake associated with the erythrocyte transketolase activity coefficient (\u3b1ETK) < 1.15, generally considered to reflect an adequate thiamin status, or with the restoration of normal (baseline) erythrocyte transketolase activity, without a sharp increase in urinary thiamin excretion, can be used to estimate thiamin requirement. In the absence of new scientific evidence, the Panel endorses the average requirement (AR) of 0.072 mg/MJ (0.3 mg/1,000 kcal) for all adults proposed by the Scientific Committee for Food (SCF) in 1993 on the basis of one depletion\u2013repletion study, in which both \u3b1ETK and urinary thiamin excretion were measured. Results from other depletion\u2013repletion studies are in agreement with this value. The Panel agrees on the coefficient of variation of 20% used by the SCF to cover uncertainties related to distribution of thiamin requirements in the general population, and endorses the population reference intake (PRI) of 0.1 mg/MJ (0.4 mg/1,000 kcal) set by the SCF for all adults. The same AR and PRI as for adults, expressed in mg/MJ, are proposed for infants aged 7\u201311 months, children aged 1 to < 18 years, and during pregnancy and lactation, under the assumption that the relationship between thiamin requirement and energy requirement is the same in all population groups

Association of maternal diet, micronutrient status, and milk volume with milk micronutrient concentrations in Indonesian mothers at 2 and 5 months postpartum

BackgroundMaternal micronutrient deficits during preconception and pregnancy may persist during lactation and compromise human milk composition.ObjectiveWe measured micronutrient concentrations in human milk and investigated their association with maternal micronutrient intakes, status, and milk volume.MethodsInfant milk intake (measured via a deuterium dose-to-mother technique), milk micronutrient and fat concentrations, and maternal micronutrient intakes were assessed at 2 and 5 mo postpartum in 212 Indonesian lactating mother-infant pairs. Maternal hemoglobin, ferritin, transferrin receptors, retinol binding protein (RBP), zinc, selenium, and vitamin B-12 were measured at 5 mo (n = 163). Multivariate or mixed effects regression examined associations of milk micronutrient concentrations with maternal micronutrient intakes, status, and milk volume.ResultsPrevalence of anemia (15%), and iron (15% based on body iron), selenium (2.5%), and vitamin B-12 deficiency (0%) were low compared with deficiencies of zinc (60%) and vitamin A (34%). The prevalence of inadequate intakes was >50% for 7 micronutrients at 2 and 5 mo. Median milk concentrations for most micronutrients were below reference values, and nearly all declined between 2 and 5 mo postpartum and were not associated substantially with milk volume (except for β-carotene, α-carotene, and β-cryptoxanthin). At 5 mo postpartum, associations between maternal micronutrient status and corresponding milk concentrations reported as mean percentage difference in human milk concentration for each unit higher maternal biomarker were significant for hemoglobin (1.9%), iron biomarkers (ranging from 0.4 to 7%), RBP (35%), selenium (70%), and vitamin B-12 (0.1%), yet for maternal intakes only a positive association with β-carotene existed.ConclusionsMost milk micronutrient concentrations declined during lactation, independent of changes in human milk production, and few were associated with maternal micronutrient intakes. The significant associations between maternal biomarkers and milk micronutrient concentrations at 5 mo warrant further study to investigate whether the declines in milk micronutrients are linked to shifts in maternal status