Managing iron nutrition

Material in this section is for general information only. A physician should be consulted for possible applications to personal health and for interpretation of laboratory test results.

Most individuals eagerly adopt measures to preserve health depending on availability, cost, and common sense. Seat belts, bike helmets, gun safety in the home, sunscreen and radon detectors are obvious. Pap’s tests and breast self-examination take minimal effort. Diet and exercise are more challenging. Maintaining optimal iron nutrition should not be too difficult because blood tests indicate levels of body iron and iron intake can be adjusted. This section describes current information on levels of iron believed to be at-risk and provides guidelines on how to limit accumulation of excess iron. In some respects the problem of iron excess is related to the problem of iron deficiency (or more precisely, its prevention) but other sources should be consulted for information primarily on iron deficiency.

At present, managing risk of iron excess is more difficult than it should be for several reasons.

First, popular culture inappropriately idealizes ingesting lots of iron as symbolized by Popeye and Superman, “the man of steel” prompting many to reach for the iron without thinking twice. However, highly conditioned athletes typically have low levels of body iron while maintaining peak physical performance. The solution to this misperception rests with the popular media.

Second, data from the Framingham Follow-up Study has shown that ingestion of iron-containing vitamin and mineral supplements is the number one contributor to elevated body iron levels in an aging population. Such supplements taken because of the (usually mistaken) belief that they contribute to health are badly labeled. The iron content is usually in fine print and may be difficult to find. The packaging literature for some products marketed to men, post-menopausal women or individuals with grey hair states that they contain no iron because iron may be hazardous to health with aging. Sadly, this rationale is not stated explicitly on the container. Limitation of iron intake may need to be started long before the individual gets grey hair. The solution to this problem is simply proper labeling by manufacturers. Government - mandated warnings cover almost every conceivable product. Risks from iron excess are a striking exception presumably because excessive iron is mistakenly believed to have no ill effects. Individuals may avoid this important source of excess iron by reading labels carefully, consulting with a pharmacist to be sure and not taking supplements at all unless advised to do so by their physician.

Physicians may diagnose iron deficiency following, for example, a surgical procedure associated with bleeding or in women with excessive menstrual blood loss (menorrhagia). Therapy with pro-hemostatic drugs can prevent iron deficiency by reducing blood loss. However, anemia may have various causes and should be treated with iron only after iron deficiency is diagnosed by blood testing. Detection of iron deficiency without obvious blood loss must be evaluated carefully because it may be due to serious internal disease.

Third, we are flooded with iron because of supplementation of manufactured foods (especially cereal grains) that has been public health policy in the United States for over 60 years. Whether iron supplementation has been successful in reducing iron deficiency is not at issue here. The point is that the vast majority of individuals that ingest foods supplemented with iron are not - and never will be - iron deficient. Such supplementation represents treatment for a condition they do not have, that is taken involuntarily (without consent) and that contributes to disease risk with aging. Concern about iron deficiency is justified but concern about iron excess is at least equally justified. It is reasonable to suppose that individuals dying of natural causes since implementation of involuntary iron therapy without iron deficiency have had their life expectancy reduced to some extent because of this practice. The solution is to eliminate “shotgun” iron supplementation for the problem of iron deficiency. Manufactured foods should be prepared with or without added iron and the packaging labeled accordingly to informed consumer selection. Iron deficiency is a serious condition that must be diagnosed properly, its cause eliminated if possible, and corrected by treatment after which iron therapy should be stopped.

Managing Iron Excess

Toxicity from chronic exposure to excessive levels of iron should be preventable by either avoiding excess intake over time or by active intervention. Iron levels decline when daily intake is less than daily loss (which reduces iron slowly) or by removing blood (which reduces iron rapidly).

All foods contain iron because iron is essential for life. However, food iron content and availability are highly variable. In general, iron in plants is poorly absorbed while iron in meat is readily absorbed. Iron availability from red meat is greater than from poultry or fish. Individuals concerned with iron excess should limit intake of red meat to about two servings per week. For foods manufactured from cereal grains, the percent of the daily requirement present per serving is less important than whether iron has been added in manufacturing. This is because iron levels in whole grains, nuts, raisins, berries, etc. in the product are relatively high but such vegetable iron is poorly absorbed and contributes little to absorbed iron. This is true for spinach iron as well. Cereals can be found that provide less than 10% or even less than 6% of the daily requirement.

Iron added to manufactured foods is typically “reduced iron” which is well-absorbed powered elemental iron. The few cereal products that do not have iron added in manufacturing can be identified from the ingredients list in the side panel (which is different from the percent of daily requirement). Examples include Rice Crunch-Ems (Health Valley) and Shredded Wheat (Post) among others. Manufacturers must indicate clearly on the front of the package in bold lettering whether or not iron has been added. Additional information on management of dietary iron intake can be obtained from www.irondisorders.org and other patient advocacy groups concerned with iron excess.

Drugs exist that bind iron and increase its removal from the body. Such drugs are used to treat extreme iron overload that occurs in individuals who have received many blood transfusions. These drugs are expensive and toxic, and not appropriate for general use. Research currently underway seeks to develop safe and effective iron-binding drugs (often based on substances present in foods that bind iron naturally) that are more suitable for general use.

Blood removal is a safe method for rapid and precise iron reduction. Iron loss is natural for menstruating women but no such natural source of blood loss exists in men. Studies of routine blood donors have shown improvement in health status with donation of two or three units per year. Iron lost from donating this amount of blood is very close to the amount of iron absorbed in excess of requirements per year in the average individual. This blood volume is almost identical to the amount of blood lost per year in the average menstruating woman and to the amount of blood removed per year to improve health in the clinical trial of iron reduction described in section 4 of this web site.

Management of iron excess based on measuring body iron

The serum ferritin blood test reflects the amount of iron in the body. As the amount of iron in the body increases, cells respond by producing ferritin that binds to the excess iron to limit its toxicity. Ferritin does its job effectively but only within limits. According to current concepts, iron can rise to levels above which the protective effect of ferritin is exhausted. Increasing iron present for a longer time is correlated with increasing ferritin levels and greater tissue damage. The fact that iron accumulates imperceptibly and causes damage over relatively long periods of time likely accounts for the general lack of awareness of the association between ferritin (iron) levels and disease. The gradual rise in body iron, represented by rising ferritin levels, over a period of years has been shown to commence in the late teens for males and following menopause in females; iron accumulation over time is much greater in blacks than in whites. (See analysis of the NHANES database. in section 2 of this web site). The ferritin level also rises during inflammation (including the post-operative period and following trauma) but is generally a reliable guide to iron levels in the absence of such diseases. Although the ferritin test has shortcomings, it is currently the best test available for measuring levels of body iron.

The normal ferritin level

 It is customary to define the range of normal for a laboratory test based on assays on healthy people. This approach is not useful for defining unsafe elevation of ferritin (iron) levels because people at risk of age-related disease (such as cancer or vascular disease) usually feel well until the disease becomes obvious. The rise in iron levels that contribute to the disease is not sensed and free-living apparently healthy individuals having relatively high (at-risk) ferritin levels are sampled and included in the “normal range” calculation.

Ferritin levels below about 12 to 15 ng/ml are characteristic of iron deficiency. The population average for the ferritin during childhood and in menstruating women (when health is optimal) is about 25 ng/ml. Evidence based on low risk of disease suggests that the upper limit of normal for the serum ferritin is about 50 to 70 ng/ml. (Note that the ferritin may be higher than this with iron deficiency because of a co-existing inflammation or other disease. Likewise, a ferritin level higher than this need not indicate risk for the same reason. Your physician can help with interpreting your ferritin level and may recommend other tests when uncertainty exists).

The upper limit of normal (above which disease risk increases) must be defined by correlating ferritin level with that disease risk. For example, studies have shown that the thickness of the carotid artery wall begins to increase (reflecting atherosclerosis) with levels above about 50 to 60 ng/ml. In a study of diabetes risk the average ferritin in healthy women who later developed diabetes was 109 ng/ml while the average in healthy women who did not develop diabetes was 71 ng/ml. In the randomized trial of iron reduction described in section 4 of this web site, disease risk was increased with ferritin levels above about 50 to 60 ng/ml. The goal of treatment of individuals with the iron overload disease, hemochromatosis, is to remove blood sufficient to achieve a ferritin level in the range of 25 to 75 ng/ml. It is typical to find at-risk ferritin levels in free-living adults considerably above the 60 to 70 ng/ml range. Patients can learn to interpret their own ferritin levels with physician coaching and experience just as a diabetic learns to interpret their blood sugar level.

Reducing iron excess by blood drawing

Reducing iron intake is the mainstay for preventing iron toxicity. However, some individuals may require more rapid iron reduction by blood drawing (see sections 3 and 4 of this web site). One unit (pint) equals 500 ml of blood. Moving the decimal point one place to the left approximates the decrease in ferritin level with blood removal. Thus, removal of 500 ml of blood will lower the ferritin level by about 50 ng/ml.

Sample calculation:

1. A patient has a ferritin level of 230 ng/ml and the objective is to reduce this level to about 15.
2. The ferritin needs to be reduced by 215 ng/ml (230 - 15 = 215).
3. The amount of blood that must be removed is 215 X 10 = 2150 ml.
4. Removal of four units of blood (500 ml X 4 = 2000) will achieve a ferritin of about 30 ng/ml (close enough because it is between 15 and 50, unless the person is on a research protocol).
5. When it is necessary to remove many units of blood to achieve the desired ferritin reduction, a few units may be removed, the ferritin level measured again in about a week, and the targeted amount of blood to be removed re-calculated.
6. Typically, blood is removed one unit (500 ml) at a time at intervals of one to two weeks.

After achieving a targeted ferritin level (in this example 30 ng/ml), the ferritin can be re-checked every 6 months and the above procedure repeated. The typical increase in ferritin with an average diet is about 0.2 ng/ml/day. If sufficient blood is removed to achieve a ferritin of 30 ng/ml (this is a calculated - not a measured - value), the patient should be up to about 65 ng/ml in 6 months. Six months = 180 days. 180 X 0.2 = about 36 ng/ml increase in 6 months. 36 ng/ml accumulation + 30 ng/ml starting ferritin = 66 ng/ml after 6 months. In the randomized trial of iron reduction, it took removal of an average of about 411 ml every 6 months to keep patients in the targeted range. This calculated amount might vary somewhat between patients. Fractions of a unit may be removed if necessary to fine-tune the amount of iron removed from the body. It is likely that maintaining a strict upper limit for the ferritin will not be necessary because elevated levels exert their effect over time.

Routine blood donation by qualified donors is a highly desirable and altruistic. However, the Red Cross has strict rules governing who may donate blood for infusion into another individual and prospective donors must be meet eligibility criteria. The American Red Cross and other blood collection agencies remove blood in one-unit (500 ml) volumes. Measuring the serum ferritin can refine the decision on whether an eligible donor should give blood.

Drawing blood in calibrated amounts to reduce body iron or to prevent its accumulation to reduce disease risk may become more common in the future as more information becomes available on the therapeutic value of controlling iron levels (see sections 3 and 4 of this web site). However, reducing iron intake remains the ideal method for controlling iron levels.

Summary

1. Individuals seeking to control body iron levels should consult with a physician about their health and about testing to determine the amount of iron in their body.
2. Monitor the ferritin level about once or twice per year and learn to interpret your serum ferritin level. Testing at intervals will show trends in iron levels over time and whether ferritin levels reflect amounts of iron or some other illness apart from iron levels.
3. Read the labels on vitamin and mineral preparations and do not ingest iron or iron - containing products unless you are tested and found to be iron deficient.
4. Avoid excess vitamin C that enhances iron uptake.
5. If possible, choose prepared foods (such as breakfast cereals) with the lowest per-cent of the daily requirement of iron and no added iron (iron is not in the ingredients list). Products with 6% or less of the daily requirement and no added iron can be found.
6. Eat a diversified diet rich in whole grains and vegetables in which red meat (limited to two servings per week) is alternated with poultry, fish and vegetarian meals. Avoid one-theme diets such as those with high consumption of fruits.
7. Determine whether you are qualified to be a blood donor and aim to donate about 2 or 3 times each year unless your ferritin falls to near iron deficient levels.
8. Learn more about iron nutrition and keep track of developments in this field. Return to this site from time to time. Its content will change as more information becomes available.