Iron deficiency is common in Switzerland and the main reason for anaemia. Nearly one in five premenopausal women suffers from iron deficiency. Low iron intake, reduced iron resorption or loss of blood are the main cause for iron deficiency. Symptoms of iron deficiency, for example fatigue, weakness, headache or exercise intolerance are primarily due to anaemia, but the same symptoms may also be present in non-anaemic patients with low serum ferritin. Consequently it is important to detect and treat non-anaemic iron deficiency. Common side effects of oral iron supplementation are primarily gastrointestinal symptoms like nausea, vomiting, diarrhea or abdominal pain. There is a positive correlation between appearance of gastrointestinal symptoms and administered iron dose. To date, only few studies have investigated effectiveness of low-dose iron supplementation in different target groups. The aim of this study is to investigate if low dose iron supplementation with 12mg iron per day for 8 weeks is sufficient to increase serum ferritin levels into a normal range in healthy premenopausal women suffering from non-anaemic iron deficiency

Inclusion Criteria:

• Informed Consent as documented by signature
• Female gender
• Premenopausal
• Age > 18 years
• Regular menstrual cycle
• BMI in normal range (18-25 kg/m²)
• Serum-ferritin <30ng/ml
• No anaemia
• symptomatic iron deficiency in the past
• No intake of dietary supplements

Exclusion Criteria

• Intake of dietary supplements
• Pregnancy
• Hypermenorrhea
• Anaemia
• Serum-ferritin >30ng/ml
• BMI <18 kg/m² or >25 kg/m²
• chronic inflammatory diseases (e.g. colitis)
• Hypersensitivity to iron-supplements
• psychiatric disorder