Iron Revisited: Alternate-Day Oral Iron Supplementation in Endurance, Intermittent, and Power/Strength Female Athletes Aged 16-35

What this Trial Is About

Researchers are studying how different types and doses of oral iron supplements affect iron levels, athletic performance, and gut health in young female athletes with low iron stores. The trial compares a low-dose iron supplement, a low-dose yeast-bound iron supplement, and a high-dose iron supplement to find which works best and causes fewer stomach issues. This research focuses on female athletes aged 16 to 35 who have suboptimal ferritin levels and are competitively trained. Participants will be randomly assigned to take one of the three iron supplements every other day for 12 weeks. The supplements are encapsulated to keep the study blinded and include a low-dose ferrous sulfate, a low-dose yeast-bound iron (Lalmin® Fe10), and a high-dose ferrous sulfate. They will take the supplement within 30 minutes of morning training or upon waking if no morning training occurs. Follow-up visits occur at 4 and 8 weeks for blood tests and food logs, and participants will complete fitness tests before and after the intervention. During the study, participants will have six in-person visits for screenings, fitness assessments, and sample collections including blood, stool, and small intestine samples using SIMBA capsules. They will complete regular online surveys about sleep, stress, menstrual cycles, and gut symptoms. Researchers will measure changes in iron blood markers, gut bacteria, aerobic and anaerobic performance, body composition, and gastrointestinal health. Safety and supplement adherence will be monitored throughout the trial, which lasts about 12 weeks plus screening and follow-up assessments.

Improving Iron Levels in Female Endurance, Intermittent, and Power/Strength Athletes Aged 16-35