About 

Iron is very important for our body and is essential for every human cell. Its main function is the formation of hemoglobin, the oxygen carrier of the red blood cell. Thus, iron deficiency can result in anemia, a common health problem both in developing and developed countries. Young children, pregnant women and non-pregnant women of reproductive age are the most vulnerable groups. There are various approaches to treat iron deficiency, the intake of oral iron supplements is one of them. Today’s recommendations on iron supplementation differ often in dose, regimen and length.
  
Recently it was shown in several successive iron absorption studies in Zurich that 24 h after the intake of an oral iron dose of > 60 mg iron the uptake of iron in the body is impaired. The hormone hepcidin, which regulates the uptake of iron in the body could be associated with this reduction in iron uptake. Furthermore, it was measured that iron supplements, which are only taken every second day instead of every day, were taken up better by about 30-50% and the women had less gastrointestinal side effects. There is little knowledge about the long-term benefit of this alternating regimen on iron status and the occurrence of side effects.

To maximize iron absorption of supplements, it is often recommended to take the
iron supplements with a source of vitamin C, as well as at least one hour before breakfast and not together with coffee or tea. Vitamin C is the most efficient enhancer of non-heme iron absorption. Phytic acid, which is found in cereal products and legumes, polyphenols (found, for example, in coffee, tea, and wine), calcium, and various animal proteins are important inhibitors of iron absorption of non-heme iron. However, the iron absorption enhancing or inhibiting effects of these foods have been shown only with respect to dietary amounts of iron (up to 10 mg). 
 
CAPS Study:  
In this study, we will compare in young iron depleted women with or without mild anemia two different dosing schemes for the intake of oral iron supplements: daily intake of 100 mg iron for 3 months vs. alternate day intake of 100 mg iron for 6 months. Iron status, gastrointestinal side effects and inflammation markers will be compared between the two groups at different time points.
 
IDEA Study: 
In this iron absorption study, we would like to investigate the effects of vitamin C, coffee, a standardized breakfast, and time of day on iron absorption from a commonly used iron supplement (Ferrum Hausmann 100 mg, Vifor). This will allow us to maximize iron absorption from iron supplements and optimize current recommendations for iron supplement use. All study participants will take 6 iron capsules in combination with different foods (vitamin C, coffee, standardized breakfast) and at different times of the day (morning vs. afternoon).
 
We expect these studies will provide important information on how oral iron supplements should be best taken in order to maximize iron uptake and minimize gastrointestinal side effects. We will comply with all relevant internationally accepted guidelines. The studies have been reviewed and approved by the ethics committees of the canton Zürich (KEK).