Omega-3 Supplementation for Menstrual Pain and Running Performance in Endurance Trained Females

Intervention: Omega-3 (Fish Oil) Supplementation for Menstrual Pain and Running Performance (Comparator: Placebo, Flaxseed Oil drink) Why: Menstrual pain affects 70–80% of physically active females and is associated with reduced exercise performance. Omega-3 fatty acids (EPA/DHA) may reduce menstrual pain, inflammation, and improve endurance performance, but have not been tested in endurance-trained females. The intervention aims to determine whether daily Omega-3 supplementation for two menstrual cycles reduces menstrual pain and improves 5 km running performance relative to placebo. Materials: Participants receive 200 mL single-serve drinks daily for ~8 weeks (two menstrual cycles). Both the Omega-3 and placebo drinks are manufactured by Smartfish. Omega-3 Drink Composition (per 200 mL) Fruit juice (apple, pear, pomegranate, aronia): 172 g Whey protein: 14 g Fish oil: 10.2 g EPA: 0.8 g DHA: 1.2 g Stabiliser (pectin): 1.2 g Flavour: 0.6 g Malic acid: 0.4 g Tocopherol-rich extract: 0.02 g Vitamin D: 200 µg Placebo Drink Composition (per 200 mL) Identical to the Omega-3 drink except: Rapeseed oil: 10.2 g (no fish oil) 0 g EPA & 0 g DHA Both drinks are similar in appearance, taste, and packaging. Supplementation Procedures: Participants are randomly allocated to Omega-3 or placebo at Visit 3. They take one 200 mL drink daily for ~8 weeks with their evening meal. Compliance is monitored via: - Daily online survey reporting supplement intake - Pre- and post-intervention omega-3 index blood samples Co-intervention Study procedures: Participants also complete: - Daily menstrual cycle symptom monitoring via MCS-MT - Daily ovulation testing for up to 10 days per cycle - Food diaries before testing visits and for 3 days during supplementation - Five laboratory visits including fitness testing, 5 km time trials, anthropometry, blood sampling, and optional menstrual-fluid collection Who Provides the Intervention: - Omega-3 and placebo Drink provided by Smartfish Nutrition - Supplement allocation, physiological testing, and supervision are conducted by trained exercise physiology and nutrition research staff at Deakin University. Delivery of Intervention: - Supplements are self-administered at home once daily. - Lab-based assessments are supervised face-to-face by qualified researchers. Where: - All testing occurs at Deakin University Burwood Campus exercise physiology laboratories. - Supplement ingestion, symptom tracking, and ovulation testing occur at home. When and How much: Dose: 200 mL drink per day (2 g EPA+DHA for the active group). Duration: Two menstrual cycles (~8 weeks). Timing: Taken with the evening meal. Lab visits: 5 visits over ~9 weeks. Laboratory Visits: Visit 1 (Familiarisation): Familiarisation 5km run on a treadmill Visit 2 (Baseline Physiology Testing): Vo2max test, fatmax test, anthropometric measures (weight, height, % body fat) Visit 3 (Pre-supplementation): venous blood sample, finger prick sample, collection of menstrual fluid, 5km run time trial, Quality of Life questionnaire and Menstrual Cycle Symptom Monitoring Tool questionnaire Visit 4 (Repeat Physiology Testing): same as visit 2 Visit 5 (Post-supplementation): same as visit 3 All visits will be approximately an hour long. Timeline: Visit 1: at least 3-5 days before Visit 2 Visit 2: approximately 7 days before period Visit 3: day 2-3 of period (approximately 9-10 days after visit 2) Supplement with omega-3 or placebo daily starting the day after visit 3 for two menstrual cycles until Visit 5 (approximately 8 weeks). Visit 4: approximately 7 days before period (approximately 6.5 weeks after they started supplementing) Visit 5: day 2-3 of period (approximately 8 weeks after they started supplementing and 9-10 days after visit 4). See figure 1 in plain language statement and consent form attached in Step 11.