[Vitamin deficiency--diagnosis and therapy].

The assessment of the nutritional status involves three levels: firstly, the evaluation of the nutrient intake, secondly, the clinical examination, and thirdly, the specific biochemical evaluation. Risk factors and risk indicators for malnutrition (including vitamin deficiency) should be identified and evaluated in each patient. The therapeutic strategy depends on the etiology of the vitamin deficiency. In the case of a vitamin deficiency due to low intakes, nutrient intake should be optimized, and short-term oral vitamin supplementation may be added.