INCIDENCE OF IRON TOXICITY IS EXAGGERATED
By Michael Mooney
The toxicity of supplemental iron is highly exaggerated. While I have read people who are regarded as nutrition experts, including Dr. Mercola and Dr. Andrew Weil say, "Don't take iron because it's toxic," this notion is easily shown to be incorrect. Note that studies confirm that iron is important for cardiovascular health, hair health, brain function and immune function and iron deficiency can compromise each of these bodily functions.
Iron in multi-vitamin formulas and iron supplements in natural food stores are confirmed by US government agencies to provide doses of iron that are too low to create toxicity for normally healthy Americans.
For instance, the National Academy of Sciences' Institute of Medicine says that iron has a No Observed Adverse Effect Level (NOAEL) of 65 mg per day. This is a dose where toxicity does not occur when taken by normally healthy adults over a long period of time.
The Institute of Medicine also says that iron has a Lowest Observed Adverse Effect Level (LOAEL) of 100 mg per day. This is a dose where toxicity may be seen "rarely, but for some sensitive subgroups it may occur" when taken over a long period of time.
There Are No Toxic Iron Supplements in US Health Food Stores
Surveying the shelves of health food stores and drug stores in the United States, you will find no multivitamin supplements that contain 100 mg of iron or even 65 mg of iron. Therefore, there is no "toxic" iron in mulvitamins in the United States.
Doctors may prescribe 300 mg iron supplements, but this is done for medical reasons with the doctor monitoring the patient and conducting blood tests to be certain of the effect.
Iron carbonyl is the safest available form of supplemental iron, so if you're concerned about toxicity consider using supplements that contain iron carbonyl.
Independently published studies confirm that iron carbonyl has many times less potential for toxicity than other commonly available forms of iron at high doses.
To read about the safety of iron carbonyl go to:http://www.medibolics.com/IronCarbonylFactSheet.pdf
Then consider that the full text of the following study stated that iron absorption was strongly regulated by body stores of iron (ferritin), and said, "The powerful control of iron absorption implies that dietary iron overload cannot develop in normal subjects, even with diets having high iron content or high bioavailability."
This is another study that indicates that the "fear of iron" that has been promoted recently is exaggerated. Note that ferritin is not the same as iron in the blood, called Total Blood Iron. Ferritin is a better measure of iron in the body because it represents iron that the body has absorbed and stored. If you are concerned about iron overload, ask your doctor for a "ferritin" blood test. It is not a test that they typically volunteer, so you must ask for it.
Further, other studies confirm that ferritin levels have no association with cardiovascular disease.
Of course, if a person has an iron storage disease, any intake of iron should be monitored and approved by their doctor.
Hulten L, et al. Iron absorption from the whole diet. Relation to meal composition, iron requirements and iron stores. Eur J Clin Nutr 1995 Nov;49(11):794-808.
OBJECTIVE: To validate a new method of measuring iron absorption from the whole diet over several days, to compare iron absorption from two types of diets and to relate iron absorption to iron requirements and iron stores.
DESIGN: Iron absorption from two diets was studied in 21 healthy young women. All non-haem iron in all meals was labeled to the same specific activity with an extrinsic radio-labeled iron tracer. Haem iron (from meat) absorption was calculated from the amount of haem iron and absorption from a reference dose of iron.
RESULTS: Iron absorption was concordant with individual iron requirements measured from menstrual blood losses and body weights. Total iron absorption from one diet designed to be highly bioavailable, would cover iron requirements in about 94% of menstruating women. Iron absorption was reduced by half from a diet with less meat, more phytate and more calcium with main meals. This type of diet would cover iron requirements in only 65% of adult menstruating women. For both diets there was a marked reduction in iron absorption with increasing serum ferritin. Iron balance was not positive above a serum ferritin of about 60 micrograms/L. (Also known as 60 ng/mL)
CONCLUSIONS: Bioavailability of dietary iron is a key factor in iron nutrition. A diet with much lean meat, ascorbic acid and a low phytate content can cover iron requirements in most non-pregnant women. The powerful control of iron absorption implies that dietary iron overload cannot develop in normal subjects, even with diets having high iron content or high bioavailability.
Michael's Comment: The authors said iron balance was not positive above a serum ferritin of about 60 micrograms/l. This is because the body turns down absorption when ferritin levels reach about 60 mcg/L (Also known as 60 ng/mL), thus preventing iron overload.