Determination of Iron Absorption Mechanism From Ferrous Fumarate With GOS

Inclusion Criteria: * Female, 18 to 45 years old * SF levels 15-30 µg/L * Normal body Mass Index (18.5-24.9 kg/m2) * Body weight \<70 kg * Signed informed consent Exclusion Criteria: * Severe anaemia (Hb \< 80 g/L) * Elevated CRP \>10.0 mg/L * Any metabolic, gastrointestinal kidney or chronic disease such as diabetes, renal failure, hepatic dysfunction, hepatitis, hypertension, cancer or cardiovascular diseases (according to the participants own statement) * Continuous/long-term use of medication during the whole studies (except for contraceptives) * Consumption of mineral and vitamin supplements within 2 weeks prior to 1st supplement administration, including pre- and-or probiotics supplements (excluding foods and beverages with life cultures such as yoghurt, raw milk cheese and kombucha) * Blood transfusion, blood donation or significant blood loss (accident, surgery) over the past 4 months * Difficulties with blood sampling * Use of antibiotics over the past month * Known hypersensitivity to iron supplements in the given amount, GOS, or lactose * Women who are pregnant or breast feeding * Women who intend become pregnant during the course of the study * Lack of safe contraception, defined as: Female participants of childbearing potential, not using and not willing to continue using a medically reliable method of contraception for the entire study duration, such as oral, inject-able, or implantable contraceptives, or intrauterine contraceptive devices, or who are not using any other method considered sufficiently reliable by the investigator in individual cases * Known or suspected non-compliance, drug or alcohol (more than 2 drinks/day) abuse - * Smokers (\> 1 cigarette per week) * Inability to follow the procedures of the study, e.g. due to language problems, self-- reported psychological disorders, etc. of the participant * Enrollment of the investigator, his/her family members, employees and other dependent persons