Sources of Iron for Vegetarians
Written by Sejal Parikh-Shah N.D. B.Sc.
Iron is the most abundant mineral found in blood. The human body contains from 3.5 to 4.5 gm of iron, 2/3 of which is present in hemoglobin. The remainder is stored in the liver, spleen and bone marrow.
Purpose of iron in the body
The most important function of iron is in the production of hemoglobin and oxygenation of red blood cells. Iron is also important for growth in children, maintaining a healthy immune system and for energy production.
Iron deficiency – who’s at risk?
Iron deficiency is the most common cause of anemia. The groups at highest risk are infants under two years of age, teenage girls, pregnant women and the elderly. Iron deficiency may be due to an increased iron requirement, decreased dietary intake, diminished iron absorption or utilization, blood loss, or a combination of factors.
A typical infant’s diet in developed countries (high in milk and cereals) is also low in iron. An adolescent consuming a junk food diet is at higher risk of iron deficiency. Blood loss is the most common cause of iron deficiency in women of child-bearing age due to excessive menstrual bleeding. Individuals who engage in strenuous exercise and perspire heavily deplete iron from the body. The population at greatest risk is the low-income elderly who often have decreased levels of iron absorption.
Iron deficiency can also be prevalent in those suffering from candidiasis, chronic herpes infections, ulcers, rheumatoid arthritis or cancer.
Ten to 25 percent of the population, mostly women, are deficient in iron. Vegetarians are not at greater risk for iron deficiency than non-vegetarians.
Iron deficiency: how it occurs
Sufficient hydrochloric acid must be present in the stomach in order for iron to be absorbed. Copper, manganese, molybdenum, vitamins A, C and the B-complex are also needed for complete iron absorption. Adequate riboflavin and vitamin D are also important.
Excessive amounts of zinc and vitamin E interfere with iron absorption.
Excessive calcium supplementation may decrease iron absorption, leading to iron deficiency anemia.
Other inhibitors of iron absorption include the common preservative EDTA, tannic acids in tea, coffee (aggravated by the addition of milk), and calcium from dairy products. The addition of modest amounts of milk or cheese to a meal of pizza or hamburger has been shown to reduce iron absorption by 50-60%.
An iron deficiency may also result from intestinal bleeding, excessive menstrual bleeding, a diet high in phosphorus, poor digestion, or prolonged use of antacids.
Phytates & fibre
Because vegetarians eat a diet naturally high in fibre and phytates, it has been assumed that they may have more difficulty obtaining iron. Phytates found in cereals, certain vegetables, roots and nuts may decrease iron absorption. Generally, however, as the phytate and fibre content of a food or diet increases, so does the iron content. Consequently, consuming foods high in these components will have less of an effect on iron status than one might expect. The higher iron intake compensates for poorer bioavailability.
Vitamin C can largely counteract the iron inhibitor effect of phytate. Phytates are also broken down by toasting nuts and seeds, soaking beans, sprouting seeds and grains, yeasting breads, and fermenting soybeans to make tempeh.
Processing of whole grains into refined grains can remove much of the phytate but also much of the iron.
Signs and symptoms
Signs and symptoms of iron deficiency are fatigue, listlessness, a decreased work capacity, breathlessness, headaches, insomnia, loss of appetite, brittle hair, spoon nails, hair loss, pallor, dizziness and a decreased ability to fight infections which is especially true in children. If you are at all concerned about the adequacy of your iron intake, it is a good idea to have blood tests done reflecting red blood cells status and iron stores (ferritin).
Sources of Iron for Vegetarians
Only about one fifth of iron in a standard diet comes from meat. Dairy products are deficient in iron unless they are enriched, but even then the iron is not very well absorbed.
Iron is found in green leafy vegetables, whole grains, and enriched breads and cereals. Other foods that contain iron include almonds, avocados, beets, blackstrap molasses, dates, kelp, kidney and lima beans, lentils, millet, parsley, peaches, pears, dried prunes, pumpkins, raisins, rice, wheat bran, sesame seeds and soy beans. Those individuals who cook with cast iron pots can also obtain iron from the pots.
To get the most out of your iron foods, consume concentrated sources of calcium at a different time from high iron foods.
Vitamin C greatly enhances iron absorption. For example: brown rice and tofu served with vitamin C foods such as tomato sauce and broccoli can double or triple your iron absorption.
For a high iron breakfast, try soaking one third cup of seven grain cereal in one half cup of soy milk overnight (throw in a few nuts, dry fruits and seeds). Next morning, add one half cup water, cook five minutes for a wonderful creamy cereal.
The recommended daily intakes (RDI) of iron for adult men and women is 10 mg and 15 mg, respectively. If you are not iron deficient then you do not need to supplement. However if you are iron deficient then supplement only with ferrous iron or an iron chelate since they are absorbed by 1-1/2 to 15 times better than ferric iron.
Not only will excessive iron intake result in a decreased ability to fight infections, but it can also increase the risk of cardiovascular heart disease and/or cancer. This can occur when iron acts as a pro-oxidant rather than as an anti-oxidant.
Sejal Parikh-Shah is a Naturopathic Doctor practicing in North York.
From the January/February 1997 issue of Lifelines.
The Dieticians Guide to Vegetarian Diets, Mark Messina, Virginia Messina, Gage Publishing, 1996.
Position of the American Dietetic Association: Vegetarian Diets, 1993.
Nutritional Influences on Illness, Werbach, Melvyn R, Third Line Press, 1993
Prescription for Nutritional Healing, Balch, J.F. & Balch, P.A. Avery Publishing Group Inc, 1990
Encyclopedia of Natural Medicine, Murray, Michael and Pizzorno, Joseph, Prima Publishing, 1991