Iron

IRON by Reed Mangels, Ph.D.,R.D.

Summary: Dried beans and dark green vegetables are especially good sources of iron, better on a per calorie basis than meat. Iron absorption is increased markedly by eating foods containing vitamin C along with foods containing iron. Vegetarians do not have a higher incidence of iron deficiency than do meat eaters.

Iron is an essential nutrient because it is a central part of hemoglobin which carries oxygen in the blood. Iron deficiency anemia is worldwide health problem which is especially common in young women and in children.

Iron is found in food in two forms, heme and non-heme iron. Hemeiron, which makes up 40 percent of the iron in meat, poultry, and fish is well absorbed. Non-heme iron, 60 percent of the iron in animal tissue and all the iron in plants (fruits, vegetables, grains, nuts) is less well absorbed. Some might expect that since the vegan diet contains a form of iron which is not that well absorbed, vegans might be prone to developing iron deficiency anemia. However, recent surveys of vegans and vegetarians (1, 2, 3) have shown that iron deficiency anemia is no more common among vegetarians than among the general population.

The reason for the satisfactory iron status of many vegans may be that commonly eaten foods are high in iron, as Table 12 (see below)shows. In fact, if the amount of iron in these foods is expressed as milligrams of iron per 100 calories, many foods eaten by vegans are superior to animal-derived foods. This concept is illustrated in Table13 (see below). For example, you would have to eat 340 calories of sirloin steak to get the same amount of iron as found in 100 calories of spinach.

Another reason for the satisfactory iron status of vegans is that vegan diets are high in vitamin C. Vitamin C acts to markedly increase absorption of non-heme iron. Adding a vitamin C source to a meal increases non-heme iron absorption up to six-fold which makes the absorption of non-heme iron as good or better than that of heme iron(4).

Fortunately, many vegetables, such as broccoli and bok choy, whichare high in iron are also high in vitamin C so that the iron in these foods is very well absorbed. Commonly eaten combinations, such as beans and tomato sauce or stir-fried tofu and broccoli, also result in generous levels of iron absorption.

It is easy to obtain plenty of iron on a vegan diet. Table 14 (see below) shows several menus which would meet the RDA (5) of 15 milligrams of iron per day for an adult woman. Men and post-menopausal women need about one-third less iron, 10 milligrams daily.

Some foods reduce iron absorption. Tea has tannin in it which binds iron in the intestines and decreases its absorption. Therefore, if you drink tea, drink it between meals. Herbal teas do not contain tannin and are an alternative to regular tea.

References

1. Anderson BM, Gibson RS, Sabry JH: The iron and zinc status of long-term vegetarian women. Am J Clin Nutr 34: 1042-1048,1981.

2. Latta D and Liebman M: Iron and zinc status of vegetarian and non-vegetarian males. Nutr Rep Int 30: 141-149, 1984.

3. Helman AD and Darnton-Hill I: Vitamin and iron status in new vegetarians. Am J Clin Nutr 45: 785-789, 1987.

4. Hallberg L: Bioavailability of dietary iron in man. Ann RevNutr 1: 123-147, 1981.

5. Food and Nutrition Board, National Research Council: Recommended Dietary Allowances, 10th ed. Washington, DC: National Academy Press, 1989.______________________________________________

Table 12: Iron Content of Selected Vegan Foods

FOOD AMOUNT IRON (mg)

Tofu, firm 4 oz 0.7-13.2

Soybeans, cooked 1 cup 8.8

Lentils, cooked 1 cup 6.6

Tofu, regular 4 oz 0.7-6.6

Blackstrap molasses 2 Tbsp 6.4

Quinoa, cooked 1 cup 5.3

Kidney beans, cooked 1 cup 5.2

Chickpeas, cooked 1 cup 4.7

Pinto beans, cooked 1 cup 4.5

Black-eyed peas, cooked 1 cup 4.3

Seitan 4 oz 4.0

Swiss chard, cooked 1 cup 4.0

Tempeh 1 cup 3.8

Black beans, cooked 1 cup 3.6

Turnip greens, cooked 1 cup 3.2

Prune juice 8 oz 3.0

Spinach, cooked 1 cup 2.9

Potato 1 medium 2.8

Beet greens, cooked 1 cup 2.7

Soy yogurt, plain 1 cup 2.7

Sesame seeds 2 Tbsp 2.6

Tahini 2 Tbsp 2.6

Peas, cooked 1 cup 2.5

Lima beans, cooked 1 cup 2.3

Sunflower seeds 1/4 cup 2.3

Figs, dried 5 medium 2.1

Cashews 1/4 cup 2.0

Apricots, dried 10 halves 2.0

Bulgur, cooked 1 cup 1.8

Bok choy, cooked 1 cup 1.8

Raisins 1/2 cup 1.6

Watermelon 1/8 medium 1.

Soymilk, plain 8 oz 1.5

Millet, cooked 1 cup 1.5

Tomato juice 8 oz 1.4

Almonds 1/4 cup 1.3

Kale, cooked 1 cup 1.2

Brussel Sprouts 1 cup 1.2

Broccoli, cooked 1 cup 1.1

Green beans, cooked 1 cup 1.1

Prunes 5 medium 1.0

Source: Composition of Foods, USDA Handbook 8. Manufacturer's information.

The RDA for iron is 10 mg/day for adult men and for post-menopausal women and 15 mg/day for pre-menopausal women.______________________________________________

Table 13: Comparison of Iron Sources

Food Iron (mg/100 calories)

Tofu, firm 7.1

Spinach, cooked 5.4

Collard greens, cooked 2.9

Lentils, cooked 2.9

Broccoli, cooked 2.2

Sirloin steak 1.6

Chickpeas, cooked 1.1

Figs, dried 0.9

Hamburger, cooked 0.8

Chicken, cooked 0.5

Pork Chop 0.4

Flounder, baked 0.3

Milk, skim 0.1

Note that the top iron sources are vegan.

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Table 14: Sample Menus Providing More Than 15 milligrams of Iron

Iron (mg)

Breakfast: 1 svg Oatmeal Plus (p. 23) 3.8 Lunch: 1 svg Tempeh/Rice Pocket Sandwich (p. 94) 4.7

10 Dried Apricots 2.0

Lunch: 1 svg Black-Eyed Peas and Collards (p. 76) 2.1

1 svg Corn Bread (p. 21) 2.6

1 slice Watermelon 1.6

----TOTAL 16.8

Breakfast: Cereal with 8 ounces of Soymilk 1.5 Lunch: Kidney Bean Chili(1 cup kidney beans) 5.21/4 cup Sunflower Seeds 2.3 Dinner: 4 ounces Seitan stir-fried with 4.0

1 cup Bok Choy 1.8 and sprinkled with 2 Tbsp Sesame Seeds 2.6 ----TOTAL 17.4

Additional foods should be added to these menus to provide adequate calories and to meet additional nutritional requirements.

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This article originally appeared in _Simply Vegan_,published by:

The Vegetarian Resource Group P.O. Box 1463 Baltimore, MD 21203(410) 366-VEGE

For questions or comments on this article, please contact Brad Scott atbrad@clark.net. This article is copied with the permission of the authors.Copyright 1991 by Debra Wasserman and Reed Mangels, Ph.D., R.D. The contents of this article, as with all The Vegetarian Resource Group publications, is not intended to provide personal medical advice.Medical advice should be obtained from a qualified health professional.