Ferrous sulfate is rapidly absorbed and the bolus of iron enters blood rather quickly possibly leading to higher concentrations of non-transferrin bound iron which induces oxidative stress. The objective of this study was to determine how quickly iron enters into blood stream from the iron-enriched Asperigillus oryzae (AspironTM, ASP) in contrast to ferrous sulfate. Seventeen healthy, female subjects (18-35 y) were randomized, double blind, cross-over experimental design with three treatments: 10 mg iron as FeSO4 and ASP as well as 20 mg iron as ASP.

In a double-blinded cross-over design, 17 research participants were randomly given one of three iron-treatments : ferrous sulfate (10mg), AspironTM (10mg), and AspironTM (20mg). Each iron treatment was given with a test meal consisting of cabbage, green peas, green beans, soy sauce, peanut oil, 40 g baby carrots, steamed rice, and orange juice. Each subject consumed a meal with one of the three iron supplements in a random order and all participants consumed the three supplements 2 weeks in between each treatment. Prior to consuming the test meal with iron supplement for each treatment, blood was collected for baseline serum iron measuremt. Following consumption of the meal with iron, subsequent blood draws were taken every 30 minutes over the time period of 4 hours to assess the incease in serum iron. Ferritin, hepcidin, iron , and c-reactive protein concentrations were measured in the serum at baselime. After two weeks other treatments were administered to each participant. The serum iron response curves for each treatment were constructed and the area under the curve (AUC) was calculated with the change of serum iron from baseline.

Inclusion Criteria:

• Non-pregnant
• Non-lactating
• Non-smoker
• Not taking medications
• Not taking dietary supplements (vitamins or minerals)
• No history of gastrointestinal conditions

Exclusion Criteria:

• Any history of gastrointestinal conditions
• On medications that interfere with iron absorption
• Unwilling to stop taking dietary supplements (vitamins or minerals)
• Pregnant
• Lactating
• Smoker

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Both investigators and participants were blinded to the iron treatment in this double-blinded, crossover study. Three different iron supplements were given, whereby participants were either administered 10 mg FeSO4, 10 mg ASP Fe, or 20 mg ASP Fe.