There seems to be quite a stir about certain nutrients being deficient in the diet of Americans. While other nutrients may have more significance in the prevention of disease, it is generally those nutrients which have some commercial significance which receive the greatest public and media interest. The relationship of calcium to milk, vitamin C to citrus fruits, and B-12 to eggs and milk are good examples of this.
Iron is another of these special interest nutrients and many Americans are taking some kind of commercial preparation of iron for a supposed iron deficiency. Yet, the level of hemoglobin (blood iron) which most Americans carry appears to be too great for the most optimum health. Most textbooks give values for hemoglobin as 12 to 16 grams per 100 cc of blood for women, and 14 to 18 grams for men. Any value below that is considered low. These hemoglobin values would correspond to hematocrit levels of 36 to 54. These levels are too high and are not compatible with the best health as measured by freedom from complication of labor and delivery, and recuperative ability in surgery. It is probable that at sea level the ideal hemoglobin for optimum performance of the body is between 10.5 and 12.5 in women, and 12 to 15 grams in men.
If a woman complains of fatigue, her physician may suggest dietary supplements, even though her hemoglobin is above 12 grams. In one study it was found that women having babies have a better outcome of the pregnancy if the hernatocrit (packed red blood cells) before delivery varied from 29 to 33 for black women and from 31 to 35 for white women, Another study showed that men undergoing surgery have fewer complications if their hematocrits are under 40, as compared to those whose hematocrits are over 40. The improved condition of the patient is due to the easier access thinner blood has to small blood capillaries. We need to redefine what is a normal level of hernatocrit and hemoglobin.
The emphasis on giving dairy milk to children is undoubtedly one cause of juvenile iron deficiency. There are two reasons for this condi tion: milk is low in iron and dairy milk injures the lining of the digestive tract; and especially in infancy promotes the loss of blood through the bowel. Dairy milk should not be fed before 140 days of age as it has been shown that a sig nificant number of babies have blood in their stool if they are fed milk be fore that age.1
The basic mechanisms for the regulation of iron absorption are not fully understood; however, it is under stood that the need for more iron can increase the absorption of iron from the intestinal tract. It is also known that there is competition with other metals for iron binding sites at the lin ing of the intestines.
Unbelievable as it may seem with all the blood we make, there is less than one teaspoon of iron in the body of a normal healthy adult; that's about the amount in a medium nail. But its importance to our well-being is strik ingly out of proportion to the quantity we find. Sixty to seventy percent of the iron in the body is found in the blood hemoglobin. There are iron stores in the liver, spleen, bone marrow, and muscles; blood serum and certain enzymes also contain iron. When hemoglobin is broken down the iron is captured by the bone marrow, liver, or spleen, and again becomes a part of the iron stores. Hemoglobin combines with oxygen in the lungs to form oxyhemoglobin which travels to the tissues where oxy gen is released to take part in the cell processes. At that point, carbon diox ide, formed by the metabolic processes, is carried back to the lungs by the same hemoglobin.
The making of hemoglobin by the body depends on the presence of cop per, proteins, and iron. Vitamins C, E, and B- 12 also influence the rate of de struction of RBCs. Myoglobin, found only in muscle tissue, is related to blood hemoglobin both in structure and in function. It is an oxygen car rier capable of supplying oxygen to the muscles and of removing carbon di oxide.
Apart from meat and eggs, there are many other good sources of iron such as green leafy vegetables, pota toes, dried fruits, and bread. Whole grain breads and cereals are excellent sources. All dairy products are almost devoid of iron. Molasses and raisins are rich on a percentage basis, but the small quantities of these foods which are usually infre quently served make them not as important a source of food iron as whole grain breads and cereals.
Iron salts in nature are all highly col ored compounds and usually give color to a food rich in this element. Therefore, spinach could be expected to have more iron than celery, and this is the case.
Generally speaking, iron is better absorbed if the meal does not contain large varieties of food. A menu con sisting of two vegetables and whole grain bread will be better for iron absorption than a menu containing four vegetables, two fruits, and whole grain breads. Large amounts of fiber or sub stances that form insoluble complexes with iron, such as phytates and sulfur-containing compounds, reduce absorption. Prunes, dried apricots, all types of greens, peas fresh or frozen, raspberries, sweet potatoes, and car rots and cauliflower are all high in iron. Pastas (macaroni, spaghetti and noodles) from whole grains are high in iron.2
The body has built-in mechanisms for the prevention of iron overload. There are many evidences that absorp tion of too much iron by the body interferes with its function and injures its cells. Studies suggest an iron-rich environment predisposes to infections by bacteria, viruses, and fungi.3
Iron overload can occur on an acute or chronic basis. Acute effects of iron intoxication such as in children who take their mother's supplement tablets occur in the form of nausea within the hour, vomiting soon fol lowed by diarrhea and gastrointestinal bleeding. Circulatory collapse and death may follow. Up to 20% of pa tients taking oral preparations of iron complain of pain in the upper abdo men, colic, and constipation.
Despite a low intake of meat and eggs, the foods usually thought of by dieticians as the best sources of readily absorbed iron, Seventh-day Adventist vegetarian women appeared in one large study to be quite adequate in their iron and zinc status even though long-term vegetarians.4
Since there are limited ways of getting rid of iron in the body, an ex cess in the diet should be avoided. Hemorrhage is one way to get rid of excess iron. Adult men rarely lose sufficient blood through accidental hemorrhage to cause them to be defi cient in iron. Women with heavy menstruation commonly lose signifi cant quantities of iron. There is some iron excreted in the bowel movements, some from the skin through the loss of the outer layer of cells, particularly in people living in hot, moist climates. In women 50 years old the largest amount of variation in hemoglobin lost at menstruation was found. The usual menstrual loss is 60 to 80 milliliters of blood (1/4 to 1/3 cup) per menstrual period; yet, women who are unaware that their menstrual periods are abnormal may lose more than 100 milliliters (1 cup) and sometimes more than 200 milliliters per menstrual pe riod. A relatively small chronic loss of blood may significantly increase the iron requirements to maintain body stores of iron.
1. The Journal of Pediatrics 98 (4):540, April, 1981
2. Mitchell, et al. Nutrition in Health and Disease, Philadelphia, J.B. Lippincott Co. 1976
3, American Journal of Disease - Diseases of Children 135(l):18-20 January, 1981
4. American Journal of Clinical Nutrition of June, 1981
The majority of this content is taken from Dr. Agatha Thrash of Uchee Pines Institute, printed with permission by Wildwood Inn Health Retreat.