Modulation of hepcidIN With Co-supplementation of Iron and FORMulated Curcumin in Recreational Athletes

Iron deficiency and iron deficiency anaemia are common among endurance athletes partly due to a repeated post-exercise elevation of hepcidin, a hormone limiting iron entry through the intestine. Oral iron supplementation also causes stimulation of hepcidin that adds on to the exercise-intrinsic stimulation of this hormone further reducing iron absorption. Both oral ferrous iron therapy and performance running are known to cause undesired gastrointestinal symptoms. Curcumin, a polyphenol from turmeric, has been previously shown to reduce hepcidin levels in resting individuals and to protect the gastrointestinal (GI) function but its effect on active individuals supplementing with iron remains unclarified. The objective of this research study is to learn about the effects of a formulated curcumin (HydroCurc®) on intestinal health and regulation mechanisms of body iron levels in recreationally active athletes supplementing with iron. The main questions to answer are: Does HydroCurc® influence iron regulatory mechanisms in resting conditions? Does HydroCurc® influence iron regulatory mechanisms in post-exercise conditions? Does HydroCurc® alleviate iron supplementation- and exercise-related gastrointestinal adverse events Researchers will compare HydroCurc® to a placebo (a look-alike substance that contains no drug) to see if there are any significant changes. Participants will: * Perform a fitness test * Take iron and HydroCurc for seven days * Complete questionnaires on their gastrointestinal health * Complete anthropometric testing * Undergo blood sampling

Intervention study with two treatment groups in a randomised, double-blinded, placebo-controlled, crossover design. Healthy recreationally active athletes will perform a VO2 max test to determine their aerobic capacity. A blood sample will be taken prior to the test as baseline measurement. Following treatment with iron plus either HydroCurc or a matched placebo for a week, participants will run on a treadmill for one hour at 70% of their maximal capacity. Blood samples will be collected before, immediately after, one hour post- and three hours post-exercise. Gastrointestinal symptoms will be assessed via validated questionnaires during the supplementation period and the experimental visits. All participants will observe a minimum of a two-week washout period. All participants will attend visits fasting for a minimum of four hours.