Iron and Associated Trace Mineral Problems in Man and Animals

The typical human diet furnishes less than 6 mg iron per 1,000 kcal and does not meet the current recommended dietary allowances for critical groups because so much of the iron in whole, raw foodstuffs is removed in processing

In spite of the fact that iron is one of the more abundant elements on earth, we have a high prevalence of iron deficiency anemia in the United States (Am. Med. Assoc., 1968) and throughout the world (WHO, 1968). This is due chiefly to insufficient intake of iron to meet the dietary needs of women and children. . . Hemoglobin values below 10 g per 100 ml of blood and hematocrit values below 31 percent packed cell volume can be considered indicative of severe anemia

Of the estimated 4 to 5 g of iron in the adult body, about three-quarters is in the red blood cells, chiefly bound to protein as hemoglobin and myoglobin (Underwood, 1962). . . An important point to remember is that the body has other uses for iron in addition to hemoglobin formation

FOOD IRON

Raw whole food >>> The cereal grains generally are fairly good sources of iron. . . barley (27 mg/kg), buckwheat (=31), corn (=24), oats (=35), rice (=16), rye (=37), wheat (=35). . . teff, grown in Ethiopia - contains 1,050 mg iron per kg . . . Meats are fairly good sources of iron, generally ranging from about 12 to 33 mg per kg. . . organ meats eg liver 65-192 mg/kg. . . Legumes are good sources of iron, but most fruits and vegetables are low in iron, and boiling them in liberal amounts of water may further reduce the iron content. . .e iron concentration in the milk of human beings, cows and goats is only about 0.5 mg per L. . .

We have considered the quantity of iron present in the raw, whole food. What happens when the food is processed and cooked? On the one hand, we may remove much of the inherent iron by refining the food to suit human tastes. On the other hand we may add iron from processing and cooking equipment. . . Iron from processing equipment and from cooking utensils may add substantial quantities to the food.

Different types of wheat contain from about 30 to about 43 mg iron per kg. . . bran (149 mg iron per kg), shorts and middlings (=95), germ (=94), whole wheat flour (=33), 80% extraction flour (=13), patent flour (=8)

high levels of iron in feed grades of dried milk products . . . are "supplemented" in large measure by tramp iron from the processing equipment. . . grinding citrus pulp in a Wiley mill raised the iron content by more than 43 percent. Human foods contain less iron than formerly because utensils and machines formerly made of iron are now made of aluminum, stainless steel, and plastics

BIO-AVAILABILITY FROM SUPPLEMENTS

```Good: dihydrogen ferrous salt of EDTA, ferric ammonium citrate, ferric choline citrate, ferric citrate, ferric fructose, ferric glycerophosphate, ferrilactin, ferric sulfate, ferrous ammonium sulfate, ferrous chloride, ferrous citrate, ferrous fumarate, ferrous gluconate, ferrous sulfate, ferrous tartrate, isolated soybean protein, and black-strap molasses.

```Moderate: alfalfa meal, blood meal, cereals enriched with reduced iron, corn germ meal, eggs, ferric chloride, ferric pyrophosphate, fish protein concentrate, reduced iron, oat flour, and wheat germ meal

```Poor: ferric orthophosphate, ferric oxide, ferrous carbonate ores, smectite-vermiculite, and sodium iron pyrophosphate.

Particle size of 10 microns or less is desirable for best biological availability, but such samples tend to discolor the cereals to which they are added

Use of ferrous sulfate is recommended for all food fortification applications where its use is technically feasible.

Of the iron sources commonly used for cereal enrichment, ferrous sulfate is the only one that shows a high relative biological value. It has the disadvantage of being hygroscopic and is reported to cause rancidity in flour and other cereals that are subjected to prolonged storage. For iron fortification of liquid foods, such as milk, a soluble iron compound must be used to assure dispersion. Compounds that have been used successfully for iron fortification of milk include ferric ammonium citrate, ferric choline citrate and ferric glycerophosphate (Edmondson, 1969)—all iron sources with good biological availability.

TOXICITY AND OVERDOSE

Acute iron poisoning is usually the result of ingestion of massive quantities of medicinal iron (Greengard and McEnery, 1968), and unfortunately the more available forms of iron are also the more toxic (Shanas and Boyd, 1969). Hemosiderosis may result from prolonged oral iron therapy

A special situation exists among the Bantus where a prolonged intake of as much as 200 mg iron per day results in widespread hemosiderosis (Walker, 1956; de Bruin and others, 1970). The high iron intake is believed to come from iron vessels in which acid foods and beverages are prepared. It has long been known that such cooking utensils may contribute much to the calculated iron intake of foods (Moore, 1965), and we have found that those samples of various foods which contain much tramp iron from processing equipment tend to have higher availability of the iron than do those samples of the same foods which contain lower (inherent) iron content

The very high iron intake, estimated to average about 443 mg per person per day, comes chiefly from teff. The iron present in this cereal type seed is probably much less well utilized than the more available inorganic iron compounds. The prevalence of anemia in Ethiopia is very low, despite much malnutrition and a high incidence of parasitic infection, which usually contributes to loss of iron and development of anemia (WHO, 1968)

that the anemia of pregnancy, which is taken for granted in most of the world, does not exist in Ethiopia because of the Ethiopian high iron diet. The Ethiopian Survey (1959) also makes no mention of any problems of hemosiderosis because of continuous high iron intake