New reference values for vitamin D.

In the recent past, many studies have been published on the association between vitamin D and bone health or the risk of various chronic diseases. Thus, the D-A-CH reference values [D-A-CH arises from the initial letters of the common country identification for the countries Germany (D), Austria (A) and Switzerland (CH)] for the intake of vitamin D have been revised based on a critical review by the German Nutrition Society. Both dietary intake and endogenous synthesis contribute to the body's vitamin D status. Since different factors modulate the extent of endogenous vitamin D formation, quantification is hardly possible. Therefore, the new reference values for vitamin D intake are specified for a situation in which endogenous synthesis is completely missing. Based on the findings of the critical review, serum 25-hydroxyvitamin D concentrations of 50 nmol/l or higher are considered an indicator of an optimal vitamin D status. When endogenous synthesis is missing, adequate vitamin D intake is estimated as 20 µg per day for children, adolescents and adults. Dietary vitamin D intake from habitual diet is not sufficient to achieve this value. This gap has to be covered by endogenous vitamin D synthesis and/or additional intake of vitamin D. It is clearly stated that the desired vitamin D supply can be achieved without using vitamin D supplements by frequent sun exposure.