Iron Deficiency In Plant-based Diet - True?
Iron Deficiency is a common problems for those in a plant-based diet.
People give up eating meat and animal products such as milk, cheese, and eggs for many reasons.
But doing so may increase the risk of iron deficiency anemia, a potentially serious condition in which the body does not make enough oxygen-bearing red blood cells.
For vegetarians who eliminate meat, anemia can be due to an iron deficiency. For vegans, who give up all animal products including dairy, eggs, and even honey, anemia can also be caused by vitamin B12 deficiency.
The answer is to eat a carefully balanced diet — by getting needed iron and B12 from other sources, you should be able to stay committed to a vegetarian or vegan diet and prevent anemia.
Role of iron in our body
As a constituent of red blood cells, iron plays a central role in transporting oxygen throughout the body, releasing this life-giving substance where needed, and carrying away the metabolic waste product, carbon dioxide. In myoglobin, iron delivers oxygen to working muscles. As part of many enzyme systems, iron is a key element in the production of cellular energy, in immune system functioning, in detoxification, and in the mental processes surrounding learning and behavior.[1]
The body continuously breaks down red blood cells and builds new ones, efficiently recycling the iron reclaimed from spent red blood cells. However, each day tiny amounts of iron are lost in cells sloughed from the skin and from the inner lining of the intestine; these losses must be replaced from food or supplements.
Other causes can contribute to iron deficiency. Women of childbearing age have menstrual iron losses in the range of an extra 30 to 45 mg each month, making their dietary requirements higher than those of men. Growth and the building of new cells can deplete the small reserves of iron in infants and children. Teens experience the challenges of a powerful growth spurt and notoriously poor eating habits; in addition, girls have menstrual losses. Young obese women on poorly designed weight-loss diets are another group at risk for iron deficiency. People with blood loss for any reason (such as ulcers or blood donation) have an increased need for iron. There is also a concern regarding iron deficiency in plant-based diets. Athletes have somewhat higher requirements due to increased oxygen demands and greater iron losses.[2] More information can be found in vegan society website.
Recommended Intake
The RDAs for men and postmenopausal women are set at 8 mg of iron per day and for women of childbearing age at 18 mg of iron per day. Although a separate RDA hasn’t been set for vegetarians (including vegans), the Institute of Medicine (IOM) advises aiming for 1.8 times as much iron as nonvegetarians due to the lower bioavailability of nonheme iron from plant foods. Following this guide, vegetarian women of childbearing age are advised to get 32.4 mg of iron per day, and other adults are urged to get 14.4 mg of iron.
Partners in Crime: Iron + Vit C
Absorption from iron-rich plant foods increases markedly when foods high in vitamin C (such as red bell peppers or strawberries) are eaten at the same time because iron is converted from a ferric form to a more readily absorbed ferrous form. The citric acid in citrus fruits also enhances iron absorption. Obsolete food-combining rules that insist fruit must be eaten separately from other foods can be ignored, especially by consumers low in iron. The beta-carotene in yellow, red, and orange foods also aids iron absorption.[3]
Vegans eat plenty of fruits and vegetables, and typically get more than one and a half times as much vitamin C as nonvegetarians—a clear advantage when it comes to iron absorption. For example, 5 ounces (150 ml) of orange juice containing 75 mg of vitamin C has been shown to increase the absorption of iron from foods eaten at the same time by a factor of four. Other studies show 50 mg of vitamin C to enhance iron absorption sixfold. Eating ¾ cup (185 ml) of any of the following provides 50 mg of vitamin C: broccoli, Brussels sprouts, cauliflower, collard greens, bell peppers, snow peas, cantaloupes, citrus fruits and juices, guavas, papayas, strawberries, and vitamin C–fortified juices; so does having a kiwifruit, ¼ cup (60 ml) of sweet red bell pepper, or a big salad. Even after cooking, some vitamin C remains; for example, vegetables retain about 85 percent of their vitamin C when microwaved, 70 percent when steamed, and 50 percent when boiled. (Losses vary with cooking time and
temperature.) A large baked potato retains 30 mg of vitamin C after baking.[3] Iron deficiency in plant-based diets can be easily solved with this simple addition of Vitamin C.
In contrast, absorption of dietary iron decreases in the presence of tannins and other polyphenols in black tea, coffee, cocoa, and red wine. Calcium supplements also inhibit iron absorption. [3] To maximize iron absorption, it’s wise to consume these inhibitors an hour apart from iron sources.
Iron Sources
Some of the foods that vegans can eat to increase iron in their diet are:
- Fortified breakfast cereals, both hot and cold
- Blackstrap molasses
- Green leafy vegetables
- Dried beans, such as black and kidney beans, and lentils
- Whole grains
- Enriched rice or pasta
- Pumpkin seeds
- Prune juice
- Dried fruit, especially raisins
Multivitamins often contain iron, especially those labeled for women under age 50. You should discuss the need for taking a multivitamin with iron with your doctor, and get a recommendation for which type of supplement to purchase.
Heme or non-heme?
In the past, nutrition texts rated nonheme iron from plant foods as inferior to heme iron in meat, because the body generally absorbs a lower percentage of nonheme iron. We’re now aware that relying on nonheme iron gives the body more control over absorption efficiency, by allowing it to adjust uptakes to suit its needs. If its iron reserves are low, the body absorbs more iron from plant foods; if iron reserves are abundant, the intestines can absorb a lower proportion of nonheme iron. (Food preparation and combinations also affect absorption of
nonheme iron.) [4]
The heme form of iron found in meat and blood tends to be more readily absorbed—even when the body doesn’t need any iron. Once iron has been absorbed, the body has limited mechanisms for ridding itself of any excess.
Because iron is a prooxidant, too much in the body may damage DNA and other molecules. New research also indicates that high iron intakes and a burden of excess iron in the body have been associated with Alzheimer’s and Parkinson’s diseases, arthritis, type 2 diabetes, cardiovascular disease, and colorectal and other cancers. To avoid iron overload, consuming the nonheme form found in plants is recommended. This can help to reduce iron deficiency in plant-based diets.[4]
Although the oxidative stress of excess iron is best avoided, the body does need enough for vital functions. Iron-deficiency anemia is no more prevalent among vegans and other vegetarians than among nonvegetarians. Yet iron deficiency is the primary nutritional deficiency worldwide for people on any diet, especially for women of childbearing age, infants, and teens. In the United States, the prevalence of iron-deficiency anemia among youths and adults is estimated at 2 to 5 percent among females and 1 to 2 percent among
males.[4]
Supplements - Yay or nay?
Iron supplements are readily available, and can provide quantities of iron that range from 10 to 40 mg per daily dose. There are however potential problems with some iron supplements, of which the greatest is getting too much iron. Excess intake of iron can cause constipation, impair the uptake of essential trace minerals, and contribute to a higher state of oxidative stress (iron is one of nature’s most potent oxidants). Children who accidentally consume large amounts of iron are most susceptible to the adverse effects and the single most commonly reported poisoning from supplements is due to children getting into packages of iron supplements (all supplements providing iron are now required to have child-proof caps).
In an attempt to maximize iron supplementation without evident side effects, many suppliers of supplements for prescription by nutritionists provide 27 mg/day, the highest amount that is associated with a low incidence of complaints. In addition to maximizing iron levels in the supplements, the manufacturers also attempt to maximize its absorption by using iron glycinate and by including vitamins (mainly vitamin C and several B vitamins) that enhance the absorption of iron, helping with iron deficiency in plant-based diets.
Maximizing iron dosage and promoting efficient absorption together may not be ideal because it involves adding as much iron as possible to the system. So it is up to the wisdom of the consumer to decide.
What if I have taken iron supplements, yet still anemic?
You might need additional help other than just supplements as your absorption of iron is minimal. That’s when Traditional Chinese Medicine(TCM) can help – to boost your absorption of iron by working on your digestion. The key is persistence though.
The traditional Chinese medicine view of blood deficiency (血虚) doesn’t correspond completely to the modern medical concept of anemia. This divergence in interpretation often leads to difficulty in discussing the matter with patients. Although there are many types of anemia described in modern medicine (some of them related to rare deficiencies of blood cell production or altered hemoglobin formation), by far the most common type – and the one that might come closest to the usual description of blood deficiency in Chinese medicine – is iron deficiency anemia. The causes, such as excessive menstrual bleeding, are the same in the two systems. Iron deficiency is easily measured by taking a blood sample and evaluating its iron constituents, such as hematocrit (red blood cell proportion), hemoglobin (iron-based blood component), and serum ferritin (iron storage protein). This can be a better gauge for those who are worried about iron deficiency in plant-based diets.
Modern medical treatment of iron deficiency anemia is straightforward and easy: the main thrust is to recommend a diet rich in iron. Then, if necessary, iron supplements can be administered (many of these are available over-the-counter). The Chinese treatment of anemia most often revolves around the use of a small number of herbs, with Dang Gui(当归） as the central one. This herb is an ingredient in the principal blood nourishing formulas of Chinese medicine, such as Siwu Tang（四物汤）, Danggui Buxue Tang, Guipi Tang（当归补血汤）, and Bazhen Tang（八珍汤）. Dang Gui(当归） is not particularly rich in iron, nor are these formulas.
Iron compounds, primarily hematite, pyrite, and magnetite, are used in Chinese medicine, yet these mineral ingredients do not appear in any of the commonly-used blood nourishing prescriptions. However, an important aspect of traditional Chinese medicine in China is combining herbs with food therapies or directly with foods. Siwu Tang（四物汤), and its expanded form Bazhen Tang(八珍汤） , are usually recommended for recovery from blood loss due to menstruation; for most women, this blood loss is limited. The main formula recommended for treating severe blood loss is Danggui Buxue Tang（当归补血汤）, comprised of two herbs: a high dose of astragalus（黄芪） (30 g), with a standard dose of Dang Gui（当归 6 g）, a formula made without any iron compounds. That formula is used for the blood loss associated with childbirth, which can be significant. Evidently, Chinese herbs prescribed for blood loss are not good sources of iron even when treating severe blood loss. It is possible that the herbs promote some aspect of red blood cell production or iron metabolism leading to better retention of iron in the blood; this interpretation remains to be evaluated.
Therefore, within the realm of standard herbal practice, given the ready availability of iron compounds used in making formulas and their absence in blood tonic formulas, one may suspect that iron deficiency anemia is not a significant target of Chinese medicine therapy for blood deficiency. With our modern knowledge of the blood and its constituents and functions, practitioners may wish to find out about the patient’s blood test results regarding iron to determine whether iron deficiency is a part of a broader diagnosis of blood deficiency. If it is, dietary recommendations related to adequate iron consumption and consideration of iron supplements might be more appropriate. The issue of dietary and supplemental iron may be an important one for practitioners who prescribe herbs.
That said, I strongly you to find a skilled TCM physician to diagnose and assess your condition, especially if you are on a plant-based diet. I can’t emphasise enough – if you are having anemia on a plant-based diet, you need to persevere if you are taking TCM herbs as they take a while to take its effect on the body. Especially if you have problems such as prolonged bleeding due to fibroids, or thickened endometrium. Make sure you check out my other post about a TCM vegan diet and how a plant-based diet can affect your periods.
References
[1] Linus Pauling Institute. Micronutrient Research for Optimum Health. Online at
http://lpi.oregonstate.edu/infocenter/minerals
[2] Institute of Medicine. National Research Council. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. Washington DC: National Academies Press, 2001
[3] Hunt J. Bioavailability of iron, zinc, and other trace minerals from vegetarian diets. Am J Clin Nutr. 2003;78(suppl):633S–9S.
[4] Mangels AR et al. The Dietitians Guide to Vegetarian Diets. Jones and Bartlett Learning Ltd. 2011.