Iron supplements have the potential to make those suffering from an infectious disease and from anaemia less healthy, says Cambridge researcher Dr Dora Pereira. The iron provided by the tablets can increase the patient’s blood iron levels, but is also made available to any pathogens — bacteria, parasites or viruses — present in the patient.
Pereira’s findings are especially worrying in India, where mosquito borne pathogens such as chikungunya and malaria are a significant challenge to the nation’s health. Last year saw an outbreak of chikungunya, with more than 12,000 cases across the country reported by the end of August. Meanwhile, though the government is pledging to eliminate malaria by 2030, India is still a major contributor to the global malaria burden, accounting for 70 percent of cases in the WHO’s Southeast Asia Region which, in turn, accounts for a tenth of the global disease burden burden.
In the regions of India where these pathogens are most prevalent, iron supplements may be causing as much harm as good. Especially in the case of malaria, this issue of blood iron levels is complex. One of the symptoms of the disease is anaemia, meaning iron supplementation is often necessary. However, the parasite causing the disease is in competition with the host’s cells to acquire iron from the blood. Adding an excess of soluble iron may create more ideal growth conditions for the parasite if left untreated.
Iron is essential for the vast majority of living organisms. Microorganisms which include many human pathogens are no exception to this. Iron has the capacity to exist in the ferrous (Fe2+) and ferric (Fe2+) oxidation states. This allows it to act as a biological catalyst, able to facilitate the transfer of electrons between molecules to allow chemical reactions within a cell to occur.
Iron in the human host is typically not found in a loose, soluble form. Instead it is found as part of a complex such as haemoglobin or transferrin. Pathogens must therefore use mechanisms by which to obtain iron during transfer. This, such as the example of malaria, brings them into competition with the host. This is the reason a symptom of many pathogenic infections result in anaemia.
In the context of medical diagnosis, it may perhaps be essential upon finding symptoms suggesting anaemia to also perform check ups for a variety of diseases known to cause anaemia, as well as those known to benefit from addition of soluble iron. Testing has already taken place for many pathogens known to increase in toxicity following iron supplementation. Amongst them are Mycobacterium tuberculosis and Klebsiella pneumonia.
Addition of a large quantity of soluble iron which is then absorbed into the blood allows for easy access for any pathogens that may be present. Dr Pereira’s research has indicated that iron found in foods such as red meat and pulses is far less accessible and more slowly absorbed by the gut than that found in iron supplements.
Currently under phase II human trials are Dr Pereira’s iron hydroxide adipate tartrate (IHAT).This mimics more closely the iron found in a healthy diet than current supplements. Not uptaken as soluble iron in the gut, and so is more slowly absorbed. It is hoped this alternative to currently used medications may be more effective at treating anaemia while also not allowing excess growth of any pathogens present.