VRG > Vegetarian Journal > 1994 Issue July > Are You Getting Enough Iron, Or Perhaps, Too Much?

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Are You Getting Enough Iron, Or Perhaps, Too Much?

By Eve Shatto Walton, R.D., L.D.N.

Recent evidence shows that heart attacks may be more likely in men with higher levels of stored iron. Should Americans be concerned about getting too much iron? Interest in this question was sparked about a decade ago when researchers noticed that women have a low incidence of heart disease prior to menopause. Heart disease increases dramatically after menopause when menstrual periods stop. This was always thought to be due to a drop in hormone levels, which is associated with a decrease in the level of good HDL cholesterol. Not surprisingly, iron deficiency is less common after menopause, since iron is no longer lost in menstrual blood each month. Some researchers say that the increase in iron stores during postmenopause may lead to an increased risk for heart disease. This may be because iron can work to make the bad LDL cholesterol worse by making it even more likely to clog arteries.

Since the jury is still out on the iron/heart disease relationship, it is still too early to make recommendations about changing iron in the diet to protect against heart disease. This is especially true since iron deficiency is a common problem in this country. The best advice to prevent heart disease is still to make changes that reduce known risk factors, like limiting fat and cholesterol in the diet, exercising, and not smoking.

Hemochromatosis, an iron overload syndrome, afflicts about one in every 200 to 500 Americans. This is a genetic disorder that causes the body to absorb large amounts of iron that it does not need. Excess iron gets stored in the liver, heart, and pancreas, where it often goes undetected until mid-life when iron levels reach 5 to 50 times normal amounts. The initial symptoms, fatigue, achy joints, and weakness, are sometimes misinterpreted as iron deficiency. Severe health problems like liver disease can result. Early identification and treatment are the way to go. Some doctors believe almost everyone should be tested for this disorder. Most recommend getting tested if you have a family history of the disease or have any symptoms which have not been successfully explained and treated. Blood tests called serum ferritin and transferrin saturation, which together cost about $75 to $100, help identify whether you are storing too much iron. Treatment is relatively simple. It involves getting rid of excess iron by drawing blood, and avoiding iron supplements and foods highly fortified with iron.

Iron deficiency is the most prevalent nutrient deficiency in this country. It is estimated to affect about ten percent of the population. Pregnant women, women of childbearing age, teenage girls, and infants are at highest risk of not getting enough iron. It can lead to anemia, fatigue, irritability, headaches, and lack of energy. To prevent iron deficiency, every effort should be made to maximize iron from food sources. A good diet will safely help decrease the risk of inadequate iron and at the same time cause the least potential damage to those at risk for iron excess. A well planned vegetarian diet provides adequate iron.

How do you know if you are getting enough iron? The Recommended Dietary Allowance for iron is 10 mg daily for men and postmenopausal women and 15 mg for women of childbearing age. Women need more iron daily to replace the iron lost each month during menstruation. Eating a varied diet with emphasis on iron-rich foods is a good start to getting enough iron. Dried beans, dark green leafy vegetables, blackstrap molasses, bulgur, and prune juice are good vegetarian sources of iron. The body absorbs only about two to twenty percent of the iron available in vegetarian sources. To increase this figure, eat a vitamin C-rich fruit or vegetable at each meal. (See chart below.) Citrus fruit, leafy vegetables, tomatoes, and strawberries are good sources of vitamin C.

BEST SOURCES OF VITAMIN C

Vegetables	Fruits
Broccoli	Cantaloupe
Brussels Sprouts	Cranberry Juice
Cabbage	Grapefruit
Cauliflower	Guava
Dark Leafy Greens	Honeydew Melon
Kohlrabi	Mango
Potato (white or sweet)	Orange
Sweet Pepper	Papaya
Tomato	Strawberries
	Tangerine
	Watermelon

Another way to promote iron absorption is to eliminate coffee and tea with meals, especially those containing significant amounts of iron. Coffee has been shown to decrease iron absorption by as much as 39 percent and tea by 64 percent. This is thought to be due to tannins and other substances which bind with the iron and make it less absorbable. This effect has been shown to occur even when coffee was consumed one hour after the meal. Adding milk to coffee further decreases iron absorption. You can partially counteract this effect with vitamin C rich foods, but why not enjoy a glass of orange juice with your breakfast instead of a cup of coffee. If you must have your coffee, drink it at least one hour before mealtime to prevent interference with iron absorption.

Cooking with iron pots can significantly increase the iron content of food. This is especially true when cooking acidic foods like tomatoes. If you are still not sure you are getting adequate iron, have your diet evaluated by a registered dietitian.

Iron supplements can do more harm than good, especially in men who are more likely to have a problem with iron overload than with iron deficiency. Iron supplements should be taken only with the advice of a physician in cases where iron deficiency or an increased need for iron has been diagnosed. During pregnancy low-dose iron supplements are commonly recommended because it is difficult to meet iron needs through diet alone. Some researchers believe all supplements or products containing iron and vitamin C should come with a warning label for people at risk of iron overload. This includes multiple vitamin/ mineral preparations. Iron supplements can also cause imbalance of other essential nutrients like copper and zinc.

The golden rule, still, is that it is best to get the nutrients your body needs, including iron, from the food you eat. A well planned vegetarian diet can provide adequate iron, minimizing the risk of iron deficiency. (See chart below.) This provides the least potential harm to those at risk for iron overload. It is still too early to tell whether limiting iron in the diet will protect against heart disease.

VEGETARIAN SOURCES OF IRON

Food	Portion Size	Iron (mg)
Beet Greens, cooked	1/2 cup	1.4
Bulgur, cooked	1 cup	1.8
Blackstrap Molasses	1 Tablespoon	3.5
Figs, dried	5	2.1
Kidney Beans, cooked	1 cup	5.2
Lentils, cooked	1 cup	6.6
Lima Beans, cooked	1 cup	4.5
Prune Juice	8 ounces	3.0
Spinach, cooked	1/2 cup	3.2
Swiss Chard, cooked	1/2 cup	2.0

References on Iron
Bothwell T. The importance of assessing iron status. In: Herbert V. Diagnosis and Treatment of Iron Disorders. Hospital Practice. 1991; 26[suppl 3]: 11-16.

Dwyer JT. Health aspects of vegetarian diets. American Journal of Clinical Nutrition. 1988; 48: 712-738.

Edwards CQ, Griffen LM, Kushner JP. Disorders of excess iron. In: Herbert V. Diagnosis and Treatment of Iron Disorders. Hospital Practice. 1991; 26[suppl 3]: 30-36.

Expert Scientific Working Group. Summary of a report on assessment of the iron nutritional status of the United States population. American Journal of Clinical Nutrition. 1985; 42: 1318-1330.

Fairbanks V. Laboratory testing for iron status. In: Herbert V. Diagnosis and Treatment of Iron Disorders. Hospital Practice. 1991; 26[suppl 3]: 17-24.

Food and Nutrition Board. Recommended Dietary Allowances.Washington, D.C.: National Academy Press; 1989.

Gambino R. Routine screening for iron status. In: Herbert V. Diagnosis and Treatment of Iron Disorders. Hospital Practice. 1991; 26[suppl 3]: 41-44.

Green R. Disorders of inadequate iron. In: Herbert V. Diagnosis and Treatment of Iron Disorders. Hospital Practice. 1991; 26[suppl 3]: 25-29.

Herbert V. Should everyone be tested for iron disorders? Journal of The American Dietetic Association. 1993; 93: 1502-1509.

Monsen, ER. Iron nutrition and absorption: Dietary factors which impact iron bioavailability. Journal of The American Dietetic Association. 1988; 88: 786-790.

Morck TA, Lynch SR, Cook JD. Inhibition of food iron absorption by coffee. American Journal of Clinical Nutrition. 1983; 37: 416-420.

Mutch PB. Food guide for the vegetarian. American Journal of Clinical Nutrition. 1988; 48: 913-919.

Pennington JAT. Bowes and Church's Food Values of Portions Commonly Used. New York: Harper & Row; 1989.

Position of The American Dietetic Association: Vegetarian diets - technical support paper. Journal of The American Dietetic Association. 1988; 88: 351-355.

Position of The American Dietetic Association: Vegetarian diets. Journal of The American Dietetic Association. 1993; 93: 1317-1319.

Salonen JT, Nyyssonen K, Korpela H, Tuomilehtl J, Seppanen R, Salonen R. High stored iron levels are associated with excess risk of myocardial infarction in eastern Finnish men. Circulation. 1992; 86: 803-811.

Eve Shatto Walton is in private practice as a registered dietitian.

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