Koji Fermented Iron
Also known as: Koji fermented iron, Koji iron, Fermented iron, Ultimine® Koji Iron, ULT, Aspergillus oryzae iron complex
Overview
Koji fermented iron is a mineral supplement derived from the fermentation of substrates with *Aspergillus oryzae*, commonly known as koji mold. This process bio-enriches the substrate with iron, creating a unique iron source distinct from conventional iron salts like ferrous sulfate. It is primarily used to prevent or treat iron deficiency anemia, especially in individuals who experience gastrointestinal side effects from traditional iron supplements. A key characteristic of koji fermented iron is its lower production of non-transferrin-bound iron (NTBI) post-ingestion compared to ferrous sulfate, which may reduce oxidative stress and inflammation. While its iron absorption profile is slower and lower than ferrous sulfate, it is generally better tolerated. Research on koji fermented iron is emerging, with several human randomized controlled trials (RCTs) demonstrating its efficacy and unique absorption kinetics, though large-scale meta-analyses are still limited.
Benefits
Koji fermented iron provides bioavailable iron, effectively increasing serum iron levels, although with a lower peak and slower absorption rate compared to ferrous sulfate. For instance, serum iron area under the curve (AUC) was approximately half that of ferrous sulfate in one study, yet still statistically significant (p<0.05). A significant benefit is its ability to produce substantially less non-transferrin-bound iron (NTBI), which is a known contributor to oxidative stress and inflammation. This reduced NTBI generation suggests a lower potential for acute oxidative stress and inflammation, potentially leading to better long-term safety. While direct comparative data on gastrointestinal side effects are limited, the altered absorption profile may lead to fewer such issues. This makes koji fermented iron particularly beneficial for individuals sensitive to traditional iron supplements or those at risk of iron-induced oxidative damage. The reduction in NTBI production is clinically relevant for mitigating oxidative damage risk, even if the overall serum iron increase is statistically lower than ferrous sulfate.
How it works
Iron from koji fermented sources is absorbed via the standard intestinal iron transporters, such as DMT1, but its release into the bloodstream is more gradual. This controlled and slower absorption limits the transient iron overload in plasma that can occur with rapid-release iron salts. By reducing the peak concentration of iron in the plasma, koji fermented iron minimizes the formation of non-transferrin-bound iron (NTBI). NTBI is highly reactive and can catalyze free radical formation, leading to oxidative stress and inflammation. Therefore, the mechanism of action for koji fermented iron primarily involves a modulated absorption kinetic that reduces NTBI, thereby potentially lowering systemic oxidative stress and inflammation.
Side effects
Koji fermented iron is generally considered safe, potentially offering a better safety profile than ferrous sulfate due to its lower production of non-transferrin-bound iron (NTBI) and reduced markers of oxidative stress. Specific prevalence data for common side effects are not well-documented, but it is expected to cause fewer gastrointestinal adverse effects compared to traditional iron supplements, given its slower absorption and lower NTBI generation. Uncommon and rare side effects are not well-reported, indicating a need for further research. Standard iron interactions, such as absorption interference by calcium or polyphenols, are likely to apply. Contraindications include iron overload disorders like hemochromatosis and hypersensitivity to *Aspergillus oryzae* products. Caution is advised for special populations, as safety in pregnancy and children has not been fully established.
Dosage
Studies on koji fermented iron have utilized doses ranging from approximately 10 to 65 mg of elemental iron equivalent. Optimal dosage ranges are generally comparable to standard iron supplementation guidelines, typically within 10-65 mg elemental iron per dose. A maximum safe dose has not been specifically established for koji fermented iron, so it is prudent to adhere to general iron supplementation guidelines to prevent iron overload. Due to its slower absorption profile, koji fermented iron can be taken with meals, which may further improve tolerance and reduce potential gastrointestinal discomfort. It is typically administered as a fermented powder or extract standardized for its iron content. Absorption may be influenced by meal composition, but its slower release might reduce interference. As with other forms of iron, vitamin C may enhance its absorption.
FAQs
Is koji fermented iron as effective as ferrous sulfate?
Koji fermented iron is less rapidly absorbed and produces lower serum iron peaks but provides bioavailable iron with potentially fewer side effects, making it an effective alternative.
Is it safer than traditional iron supplements?
Evidence suggests lower non-transferrin-bound iron (NTBI) production, which may reduce oxidative stress and inflammation risks, indicating a potentially safer profile.
When should it be taken?
It can be taken with meals due to its slower absorption, which may improve tolerance and reduce gastrointestinal discomfort.
How soon will benefits be seen?
Serum iron levels increase within hours of ingestion; clinical improvement in anemia would follow the typical timeline for standard iron therapy.
Are there any risks of allergy?
There is a possible risk of allergy to *Aspergillus oryzae* components in individuals who are sensitive to mold or fungal products.
Research Sources
- https://pmc.ncbi.nlm.nih.gov/articles/PMC7053575/ – This crossover RCT with 15 healthy adults assessed Ultimine® Koji Iron versus ferrous sulfate over 8 hours. It found significantly lower non-transferrin-bound iron (NTBI) production with koji iron (p<0.01), suggesting reduced oxidative stress potential. No acute inflammatory marker differences were observed, possibly due to the healthy cohort, but the study highlighted koji iron's potential for reduced oxidative burden.
- https://pmc.ncbi.nlm.nih.gov/articles/PMC6041945/ – This RCT with 30 participants compared iron absorption from iron-enriched *Aspergillus oryzae* to ferrous sulfate. It demonstrated that iron absorption from koji iron is significant but approximately half that of ferrous sulfate at equivalent doses (p<0.05), with a delayed peak serum iron at 150 minutes. The study found no differences in CRP, indicating no acute inflammation, supporting its potential as a well-tolerated iron source.
- https://www.mdpi.com/2072-6643/11/12/2938 – While not directly on koji fermented iron, this source represents a related meta-analysis on fermented soy products and probiotics. It supports the biological plausibility of benefits in iron absorption and reduced inflammation through fermentation processes, providing broader context for the potential advantages of koji-fermented ingredients.
Supplements Containing Koji Fermented Iron
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