Revised D-A-CH reference values for the intake of biotin.

PURPOSE: The reference values for biotin intake for Germany, Austria and Switzerland lead back to a report in 2000. Following a timely update process, they were revised in 2020. METHODS: For infants aged 0 to < 4 months, adequate biotin supply via human milk was assumed and in consequence the reference value reflects the amount of biotin delivered by human milk. For infants aged 4 to < 12 months, biotin intake was extrapolated from the reference value for younger infants. Due to missing data on average requirement, the reference values for biotin intake for children, adolescents and adults were derived based on observed intake levels. The reference value for lactating women considered in addition biotin losses via human milk. RESULTS: The reference value for biotin intake for infants aged 0 to < 4 months was set at 4 µg/day and for infants aged 4 to < 12 months at 6 µg/day. In children and adolescents, the reference values for biotin intake ranged from 20 µg/day in children 1 to < 4 years to 40 µg/day in youths 15 to < 19 years. For adults including pregnant women, 40 µg/day was derived as reference value for biotin intake. For lactating women, this value was set at 45 µg/day. CONCLUSIONS: As deficiency symptoms of biotin do not occur with a usual mixed diet and the average requirement cannot be determined, reference values for an adequate biotin intake for populations from Germany, Austria and Switzerland were derived from biotin intake levels assessed in population-based nutrition surveys.

Revised D-A-CH Reference Values for the Intake of Vitamin B6.

BACKGROUND: The Nutrition Societies of Germany, Austria, and Switzerland as the joint editors of the "D-A-CH reference values for nutrient intake" have revised the reference values for vitamin B6 in summer 2019. SUMMARY: For women, the average requirement (AR) for vitamin B6 intake was derived on the basis of balance studies using a pyridoxal-5'-phosphate (PLP) plasma concentration of ≥30 nmol/L as a biomarker of an adequate vitamin B6 status. The recommended intake (RI) was derived considering a coefficient of variation of 10%. The RIs of vitamin B6 for men, children, and adolescents were extrapolated from the vitamin B6 requirement for women considering differences in body weight, an allometric exponent, growth factors as appropriate, and a coefficient of variation. For infants aged 0 to under 4 months, an estimated value was set based on the vitamin B6 intake via breast feeding. The reference value for infants aged 4 to under 12 months was extrapolated from the estimated value for infants under 4 months of age and the average vitamin B6 requirement for adults. The reference values for pregnant and lactating women consider the requirements for the foetus and the loss via breast milk. Key Messages: According to the combined analysis of 5 balance studies, the AR for vitamin B6 to ensure a plasma PLP concentration of ≥30 nmol/L is 1.2 mg/day for adult females and the extrapolated AR for adult males is 1.3 mg/day. The corresponding RIs of vitamin B6 are 1.4 mg/day for adult females and 1.6 mg/day for adult males, independent of age. For infants, the estimated value is 0.1 mg/day and 0.3 mg/day, depending on age. The AR of vitamin B6 for children and adolescents ranges between 0.5 and 1.5 mg/day, and the RI is between 0.6 mg/day and 1.6 mg/day. During pregnancy, the AR is 1.3 mg/day in the first trimester and 1.5 mg/day in the second and third trimesters; the RI is 1.5 mg/day in the first trimester and 1.8 mg/day in the second and third trimesters. For lactating women, the AR is 1.3 mg/day and the RI is 1.6 mg/day.

Revised D-A-CH-reference values for the intake of zinc.

BACKGROUND: The Nutrition Societies of Germany, Austria and Switzerland as the joint editors of the 'D-A-CH reference values for nutrient intake' have revised the reference values for zinc in July 2019. METHODS: For infants aged 0 to under 4 months, an estimated value was set based on the zinc intake via breast feeding. For all other age groups, the reference values were calculated using the factorial method considering endogenous zinc losses via intestinal losses, urine, faeces, skin and sweat, semen in men and the additional zinc requirements to build up body weight in children and adolescents as well as in pregnant women. Due to the strong influence of phytate intake on zinc absorption, the recommendations for the intake of zinc for adults are derived depending on low (0.5 mmol/day, corresponding to 330 mg/day), moderate (1.0 mmol/day, corresponding to 660 mg/day) and high (1.5 mmol/day, corresponding to 990 mg/day) phytate intake. The reference values for lactating women take into account the zinc loss via breast milk. RESULTS AND CONCLUSION: For adults, pregnant and lactating women, the recommended intake values for zinc range from 7 mg/day to 16 mg/day, depending on sex and dietary phytate intake.

Revised Reference Values for the Intake of Protein.

BACKGROUND: Following a timely update process, the nutrition societies of Germany, Austria, and Switzerland (D-A-CH) revised the reference values for the intake of protein in 2017. The Working Group conducted a structured literature search in PubMed considering newly published papers (2000- 2017). SUMMARY: For infants < 4 months, the estimated values were set based on the protein intake via breast milk. Reference values for infants > 4 months, children, adolescents, pregnant, and lactating women were calculated using the factorial method considering both requirement for growth and maintenance. For adults, reference values were derived from nitrogen balance studies; for seniors (> 65 years), reports on metabolic and functional parameters under various protein intakes were additionally considered. Reference -values (g protein/kg body weight per day) were set as follows: infants  < 4 months: 2.5-1.4, children: 1.3-0.8, adults < 65 years: 0.8, adults > 65 years: 1.0. Key Messages: The reference values for infants, children, adolescents, and adults < 65 years are essentially unchanged compared to recently published values. Scientifically reliable data published between 2000 and 2017 guided the D-A-CH Working Group to set a higher estimated value for adults > 65 years. Since the energy consumption continuously decreases with age, this new estimated protein intake value might be a challenge for the introduction of food-based nutrition concepts for older people.

The Revised D-A-CH-Reference Values for the Intake of Vitamin B12 : Prevention of Deficiency and Beyond.

SCOPE: The nutrition societies of Germany, Austria, and Switzerland are the joint editors of the "D-A-CH reference values for nutrient intake", which are revised regularly. METHODS AND RESULTS: By reviewing vitamin-B12 -related biomarker studies, the reference values for vitamin B12 were revised in 2018. For adults, the estimated intake is based on the adequate serum concentrations of holotranscobalamin and methylmalonic acid. The estimated values for children and adolescents are extrapolated from the adult reference value by considering differences in body mass, an allometric exponent, and growth factors. For infants below 4 months of age, an estimated value is set based on the vitamin B12 intake via breast milk. The reference values for pregnant and lactating women consider the requirements for the fetus and for loss via breast milk. The estimated values for vitamin B12 intake for infants, children, and adolescents range from 0.5 to 4.0 µg d-1 . For adults, the estimated values are set at 4.0 µg d-1 , and for pregnant and lactating women, they are set at 4.5 and 5.5 µg d-1 , respectively. CONCLUSION: Based on the data of several vitamin B12 status biomarkers studies, the reference value for vitamin B12 intake for adults is raised from 3.0 to 4.0 µg d-1 .

Effect of antioxidant vitamins on the plasma homocysteine level in a free-living elderly population.

BACKGROUND: The factors influencing total plasma homocysteine levels (tHcy) are of special interest in the attempt to reduce cardiovascular risk. AIM: This investigation aimed to assess the independent effects of antioxidant vitamins on tHcy in elderly people. METHODS: Our cross-sectional analysis included data of 184 subjects (≥60 years) from the longitudinal study in an aging population in Giessen (GISELA), Germany. We examined the effects of plasma levels, intake and supplementation of vitamin C, vitamin E, and ß-carotene on tHcy. RESULTS: The mean tHcy was within the normal range in this population. Serum folate, the estimated glomerular filtration rate (eGFR), and plasma vitamin C showed a negative association with tHcy in simple regression analysis. In a subsequent multiple regression analysis, eGFR, serum folate, and plasma vitamin C were the relevant independent predictors of tHcy. Intake and supplementation of vitamin C, as well as plasma levels, intake and supplementation of vitamin E, and ß-carotene were not associated with tHcy. CONCLUSION: Vitamin C may be an independent predictor of tHcy in free-living elderly people and, therefore, should be considered in attempts to reduce tHcy.