Inclusion Criteria:  female aged between 18-45 y old; SF <80 µg/L; BMI 18.5-24.9 kg/m2; weight <70 kg; signed informed consent; able to communicate and comprehend English language.  Exclusion Criteria:  anemia (Hb <12 g/dL); Inflammation (CRP > 5 mg/L); chronic digestive, renal and/or metabolic disease; chronic medications (except for oral contraceptives); use of vitamin, mineral and pre- and/or probiotic supplements in the previous 2 weeks before study initiation and during the course of the study; blood transfusion, blood donation or significant blood loss over the past 4 months; difficulties with blood sampling; antibiotic treatment in the 4 weeks before study initiation; pregnancy (tested in serum at screening) or intention to become pregnant; lactation up to 6 weeks before study initiation; earlier participation in a study using stable isotopes or participation in any clinical study within the last 30 days; unable to comply with study protocol (e.g. not available on certain study appointment days or difficulties with blood withdrawal); inability to understand the information sheet and the informed consent form due to cognitive or language reasons; smoking; unwilling to use an effective method of contraception.