Factors Affecting Iron Absorption and Mitigation Mechanisms: A review
- The biochemistry of iron metabolism in human digestive system
- Anemia and Pregnancy
- Causes of Anemia
- Anemia Signs and Symptoms
- Preventing Anemia
- Iron Supplements
- Iron-Rich Foods
- 5 Tips for Preventing Iron Deficiency
- Choose Iron Rich Foods
- Limit Food Interactions
- Harness the Power of Food Combinations
- Time Your High Iron Meals
- Smart Iron Supplementation
Factors Affecting Iron Absorption and Mitigation Mechanisms: A review
Minerals are indispensable part of a complete diet of animals. Minerals are inorganic elements that are found in all body tissues and fluids. Even though they yield no energy, they have vital roles in many activities in the body . These compounds are necessary for the maintenance of certain physicochemical processes which are essential to life because they are chemical constituents used by the body in many ways. Every form of living matter requires these inorganic elements or minerals for their normal life processes .
The value of micro-minerals in human, animal and plant nutrition has been well recognized . Deficiencies or disturbances in the nutrition of an animal cause a variety of diseases and can arise in several ways. Iron is the most abundant element on earth, yet only trace elements are present in living cells. Iron is essential to all cells of the human body. Iron is a micro-mineral that has a number of key functions. It’s a major part of hemoglobin in red blood cells; as it carries oxygen from the lungs to all parts of the body and facilitates oxygen use and storage in muscles. In addition, every cell in the body needs iron to produce energy .
Almost one-quarter of the worldwide population are affected by anemia, of which iron deficit is the primary cause . Its deficiency is linked with impaired physical work ability, reduced mood and cognitive function, and poor pregnancy related outcomes . An individual’s iron condition falls on a range (ranging from replete to depleted iron stores), iron deficiency and iron deficiency anemia. Therefore, individuals with iron deficiency are at increased risk of developing iron deficiency anemia . In spite of advances in healthcare, iron deficiency remains a foremost public health fear in both developed and developing countries, with adolescent women being mainly susceptible. In industrialized countries, iron deficiency should be easily identified and treated, and yet it is often overlooked by medical practitioners or not recognized by women as a concern . Thus, even in these countries the prevention and treatment of iron deficiency in innovative approaches are required .
The recommended nutrient intakes of an individual’s to meet the defined requirement vary, depending, among other factors, on the criterion used to define nutrient adequacy . For many nutrients to scientifically support the definition of nutritional needs across age ranges, sex and physiologic states, the information base is limited. The use of nutrient balance to define requirements has been avoided whenever possible, since it is now generally recognized that balance can be reached over a wide range of nutrient intakes. However, requirement levels defined using nutrient balance have been used if no other suitable data are available. The dietary requirement for a micronutrient is defined as an intake level which meets specified criteria for adequacy, thereby minimizing risk of nutrient deficit or excess. Measures of nutrient stores or critical tissue pools may also be used to determine nutrient adequacy. Functional assays are presently the most relevant indices of subclinical conditions related to vitamin and mineral intakes. Anaemia, the defining marker of dietary iron deficiency, may also result from, among other things, deficiencies in folate, vitamin B12 or copper .
Individual dietary inhibitory and enhancing factors exert profound influences on iron absorption . Polyphenol compounds are widely present in the human diet as components of fruits, vegetables, spices, pulses and cereals, and they are especially high in tea, coffee, red wine, cocoa and the different herb teas. The potent inhibitory effect of phytic acid on nonheme-iron absorption is well known . Polyphenolic compounds such as chlorogenic acids, monomeric flavonoids, and polyphenol polymerization products widely present in coffee and tea also strongly inhibit dietary nonheme-iron absorption . The effects of ascorbic acid (AA) in dramatically improving iron absorption have consistently been observed . Heme iron found in animal foods is also an important iron source because of its high bioavailability. In addition, many studies have suggested that the enhancing effect of muscle tissue on iron absorption is due to cysteine-containing peptides .
The biochemistry of iron metabolism in human digestive system
Iron chemistry and physiology
Iron is found on the 26th element of the periodic table and has a molecular weight of 55.85. It has two ordinary aqueous oxidation states namely ferrous (Fe2+) and ferric (Fe3+). These states enable iron to take part in oxidation/reduction reactions that are crucial to energy metabolism by accepting or donating electrons. On the other hand, this property also enables free iron to catalyze oxidative reactions, ensuing in reactive and damaging free radicals. Hence, body iron required to be chemically bound to assist appropriate physiological role, transport, and storage, with minimal opportunity for free ionic iron to catalyze harmful oxidative reactions .
The majority of the body’s iron functions in heme protein complexes that transport oxygen as hemoglobin and myoglobin. Approximately two-thirds of the body iron is in hemoglobin, a 68,000MW structure containing four subunits of heme, a protoporphyrin ring with iron in the center, and four polypeptide chains (two chains each of α- and β-globin). For transport by hemoglobin, oxygen bonds directly to the iron atom, stabilized in a Fe2+ oxidation state surrounded by the protoporphyrin ring and histidine residues. Hemoglobin iron easily binds and releases oxygen, circulating in blood erythrocytes. Myoglobin, consisting of a single heme molecule and globin, enables oxygen transfer from erythrocytes to cellular mitochondria in muscle cytoplasm . Lesser amounts of iron in the heme form function in mitrochondrial cytochromes involved with electron transfer, oxygen utilization, and the production of ATP. A small fraction of body iron functions in heme-containing hydrogen peroxidases such as catalase that protect against excessive hydrogen peroxide accumulation by catalyzing its conversion to hydrogen and oxygen .
In addition, iron also has functions in non-heme proteins that contain an iron–sulfur complex (a cubical structure of four iron and four sulfur atoms). It’s the principal form of iron in mitochondria that functioning in enzymes of energy metabolism such as aconitase, NADH dehydrogenase, and succinate dehydrogenase. Aconitase is sensitive to iron concentrations in mitochondria and cytosol. When iron is abundant, the aconitase enzyme assumes the full iron–sulfur cubic structure that is associated with carbohydrate metabolism. However, when iron concentrations are reduced, the protein loses aconitase activity and functions as an iron binding protein (IRP). IRPs interact with iron response elements (IREs) of the mRNA to regulate the synthesis of proteins involved with iron transport, storage, and use, in response to changes in cellular iron concentrations (Figure 1).
Iron absorption and metabolism
The new born infant has a total of about 250mg in the body. The total body iron in an adult male is 3000 to 4000 mg. In contrast, the average adult woman has only 2000-3000 mg of iron in her body. This difference may be attributed to lesser iron reserves in women, lower concentration of hemoglobin and a smaller vascular volume than men. Of this approximately two-thirds are utilized as functional iron such as that in hemoglobin (60%), myoglobin (5%) and various heme and nonheme enzymes (5%). The remainder is found in storage as ferritin (20%) and hemisoderin (10%) .
Control of iron uptake is undoubtedly of principal importance due to the lack of a regulated means of excreting iron. Once the food is consumed and digested, dietary iron is mainly absorbed in the duodenum and proximal jejunum. Reasonably, haem iron is absorbed more efficiently than non-haem iron, apparently by endocytosis of the intact iron–protoporphyrin complex at the enterocyte brush border. After the digestion iron from all dietary sources enters a common intracellular pool from which depending on the iron status of individuals it is either stored as ferritin in the enterocyte or exported from the enterocyte via the ferroportin transporter on the basal side of the cell. Ferroportin transports ferrous iron which is immediately oxidized to Fe3+ and picked up by transferrin to be transported to cells expressing transferrin receptors (Figure 2).
Iron status, iron deficiency and iron overload
Infants, children, teenagers, and women of childbearing age are commonly affected by iron deficiency; whereas healthy adult males are seldom deficient. Deficiency is caused by several factors, usually by a combinations of increased need (rapid growth in the young population, menstruation and pregnancy in fertile women) and insufficient uptake, which in turn may depend on other factors such as a decreased caloric intake and/or a larger fraction of calories derived from food ingredients which contains less absorbed iron .
The earliest stage of iron deficiency is characterized by loss of storage iron (indicated by ferritin) and is called iron depletion or prelatent iron deficiency. The concentrations of serum iron and the iron-carrying serum protein transferrin are normal at this stage. When iron stores are exhausted (serum ferritin
Symptoms frequently associated with iron deficiency anemia include palor, weakness, fatigue, dyspnea, palpitations, sensitivity to cold, abnormalities in the oral cavity and gastrointestinal tract, and reduced capacity for work . It further appears that even mid/prelatent iron deficiency may have significant health consequences which can be attributed to decreases in essential body iron and limitations in tissue oxidative capacity .
Iron overload is associated with increases in non-protein bound iron resulting from the physiologic iron-binding capacity being overwhelmed . Disadvantages with overload are for example increased risk for bacterial infection and cardiomyopathy. Overload can result from inborn errors in metabolism leading to hyper-absorption of iron or inadequate synthesis of the iron-binding proteins. Overload can also result from excessive absorption of dietary iron due to various causes including chronic ingestion of greater than adequate amounts of dietary iron, especially heme iron. These observations concerning of iron overload have raised the question as to whether or not general fortification of food with inorganic iron is beneficial .
Dietary and non-dietary factors affecting iron absorption
Dietary factors contribute a significant role in the development of iron deficiency and then iron deficiency anemia. Iron absorption by the gut enterocytes controls iron balance but there is no route of controlled iron excretion. This means that iron absorption is regulated by dietary and systemic factors. Dietary iron is largely non-heme iron with about 5%–10% in the form of heme iron in diets containing meat. Even though heme iron constitutes a smaller part of dietary iron, it is highly bioavailable and 20%–30% of heme iron is absorbed. Contrary, the absorption of non-heme iron is much more variable and significantly affected by other components of the diet; with 1%–10% of non-heme iron absorbed .
Moreover, iron in the environment and the diet is primarily ferric iron (Fe3+) which is insoluble and so not bioavailable. Thus, before it can be absorbed the non-heme iron has to be reduced from ferric (Fe3+) to ferrous (Fe2+) iron by dietary reducing agents, such as ascorbic acid or by endogenous ferri-reductases, such as duodenal cytochrome B (dcytB) . Ferrous iron is transported across the apical membrane of the duodenum by the divalent metal transporter 1 (DMT1), which is localized on the brush border membrane close to dcytB. As Wang & Pantopoulos, 2011 reported, the uptake of ferrous ions by dcytB is driven by proton co-transport, so an acidic duodenal pH facilitates iron uptake, and is competitively inhibited by other divalent cations.
Ascorbic acid is one of the most effective enhancer of non-heme iron absorption. Other dietary factors such as citric acid and other organic acids, alcohol and carotenes similarly enhance non-heme iron absorption . Furthermore, animal based proteins such as meat, fish, and poultry, enhance iron absorption but the bioactive component of the “meat factor” has yet to be identified. Meat also promotes non-heme iron absorption by activating gastric acid production. Conversely, absorption of non-heme iron is inhibited by phytic acid (inositol hexaphosphate and inositol pentaphosphate) in grains and cereals and by polyphenols in some vegetables, coffee, tea, and wine. These inhibitors bonded to non-heme iron so it is not available for uptake. Dietary factors influencing iron absorption are outlined in Table 1.
Haem iron absorption
- Amount of haem iron present in meat (high haem iron content boost iron absorption)
- Content of calcium in meal (high calcium content reduce iron absorption)
- Food preparation (time, temperature): may cause leaching of haem iron
Nonhaem iron absorption
- Iron status of the individuals
- Amount of bioavailable nonhaem iron
- Balance between dietary factors enhancing and inhibiting iron absorption
Factors enhancing iron absorption
- Ascorbic acid
- Meat, fish and seafoods
- Certain organic acids (citric, lactic, malic, tartaric)
Factors inhibiting iron absorption
- Presence of anti-nutrients (example phytates and tannin) in cereal based food products
- Iron binding phenolic compounds in tea, coffee, red wine,
- some leafy vegetables, herbs, nuts and legumes
- Soy protein
Source: Hallberg & Hulthen, 2000.
Dietary factors inhibiting iron absorption
Calcium: Calcium does inhibit both non-heme iron and heme iron absorption. Calcium inhibits the absorption of both heme and nonheme iron in a comparable way and thus, it is likely that this inhibition by calcium occurs after the heme iron is freed from the porphyrin ring . Calcium has been shown to inhibit iron absorption in both rats and man , reported that giving 165 mg Ca as milk, cheese or calcium chloride reduced iron absorption by 50-60% in single-meal measurements with maximum inhibition of approximately 300 mg calcium in the meal. Further increasing the amount of dairy products above a basal level of 300 mg appears to have no further inhibiting effect on iron absorption (Galan et al. 1991). However, the duration of the inhibitory effect of calcium on iron absorption has been shown to be less than two hours . On the other hand, ingestion of 1000 mg Ca as the carbonate daily with meals over a twelve-week period did not appear to be harmful to their iron status .
Phytate: During digestion, the phytate molecule can be negatively charged, indicating a potential for binding positively charged metal ions like iron . The negative consequence of phytate in bran on iron absorption was first demonstrated by Sharpe et al. (1950), using white bread and brown bran bread. This effect was earlier supposed to be because of its high content of phytate which has been demonstrated in a number of more recent studies . Brune et al. (1989) investigated the likelihood to long-term consumption of high bran containing phytate diet could induce changes in the intestine which would bring about an adaptation to the inhibitory effects of phytate on the intestinal iron absorption. They examined vegetarians and non-vegetarians and found that no adaptation of intestinal brush border to a high phytate intake and concluded that the satisfactory iron stores in the vegetarian group were due to a high consumption of organic acids like ascorbic acid.
Several methods of preparations of cereal grains including soaking, germination and fermentation have been shown to completely reduce the phytate content of cereals and vegetables under optimal conditions and could thereby eliminate their effects on iron absorption. In addition, negative effects of phytate and fiber on iron absorption have been demonstrated in the rat , found a reduction in iron absorption when high fiber breads were fed to rats. However, the magnitude of this inhibition was unrelated to the amount of phytate phosphorus or dietary fiber present in the diet.
In contrary, results from experiments by , indicated higher absorption from FeSO4 than from the endogenous Fe present in bread, both expressed as mg Fe absorbed and fractional Fe absorption. Using balance and single meal radioisotope measures, she found no differences in Fe absorption among three different breads with fiber contents of 16.1, 38.1 and 72.4 g/kg but with the same phytate concentration (6.3-6.4 g/kg) , used the exact same bread in balance measures in humans during 3 x 24 days in 6 subjects and did not find any influence of fiber concentration on iron balances. This indicates indirectly that the inhibitory effect of fiber on iron absorption is probably due to the phytate in the fiber fraction and further supports the study of Morris and Ellis (1980), who found that iron absorption in rats was higher from dephytinized bran.
Phenolic Compounds: During digestion, the phenolic compounds from the food or beverage released and can form complex with Fe in the intestinal lumen making it unavailable for absorption. Nearly all beverages reduced iron absorption depending on the amount of total polyphenols, with the inhibition of black tea the greatest at 79–94%. Few studies revealed that an amounts of only 20 mg polyphenols from black tea per meal reduced iron absorption by as much as 66%, possibly because of the higher content of galloyl esters in black tea and probably because the simple bread meal was devoid of any enhancers of iron absorption to counteract the polyphenols (Prashanth et al., 2008). Similarly, the consumption of black tea and coffee has been shown to strongly inhibit iron absorption from composite meals , with coffee having about half the inhibitory effect of tea.
Moreover, Prashanth et al. (2008) reported that adding of a tea drink to the reference meal resulted in a dramatic reduction in iron absorption in iron deficiency anemia (IDA) and controlects. According to this study, iron absorption from the reference meal consumed with 1 cup of tea was decreased by 59% (P
On the other hand, addition of milk to tea or coffee had little or no effect on their inhibitory capacity. Gaur and Miller (2015), reported that the percentage values for total dialyzable iron, total soluble iron and soluble iron. Results showed that, addition of milk to tea significantly reduced the concentration of dialyzable iron (α
Dietary factors enhancing iron absorption
Ascorbic acid: Ascorbic acid appears to be the factor which is most potent in enhancing of iron absorption particularly the non-heme iron in single-meal studies. This was reported by several authors. There are two mechanisms for this effect of nonheme iron on absorption. Firstly, it prevents the formation of insoluble and bonded iron compounds and secondly reduces ferric iron (Fe 3+) to ferrous (Fe2+) iron states .
In study by Prashanth et al, (2008) showed that when ascorbic acid added to the meal at a molar ratio to iron of 2:1, ascorbic acid increased iron absorption by 291% in the IDA group and by 270% in the control group (P
On the other hand, the long-term-effect of ascorbic acid on iron status in the body is however less clear. Adding high amounts of ascorbic acid to daily diets for a longer period have in several studies failed to increase ferritin levels although single meal absorption measures using radio iron have in the same subjects indicated that ascorbic acid enhances the iron absorption. When a glass of orange juice is included in a breakfast meat, iron absorption can be increased 2.5 times .
Meat: The absorption of iron particularly of heme iron is influenced very little by other food components in the diet with the exception of meat which enhances absorption and calcium which inhibits iron absorption . Meat also increases the absorption of nonheme iron . The mechanism behind this enhancing effect of meat on both heme and nonheme iron absorption is as yet unknown. It has however been reported by Hurrell et al. (2006) that meat enhancement of iron absorption is by multiple mechanisms involving both gastric acidity effects and chelation. Initially, meat may enhance nonheme iron absorption by stimulating production of gastric acid, and thereby promoting iron solubilization within the stomach. Thereafter, a meat factor(s) may chelate the solubilized iron in the acidic (lower pH) environment of the stomach and thereby maintain iron solubility during intestinal digestion and absorption. Fish and poultry also have an enhancing effect on nonheme iron absorption .
Alcohol: Alcohol increases the absorption of nonheme iron slightly in man . It has been shown that chronic alcohol abusers have increased serum ferritin concentrations and calculated total body iron compared with nondrinkers although it is controversial whether the alcohol affects the actual absorption process of iron.
Form of iron from various food sources
Both the source and chemical form of dietary iron can markedly affect its availability for absorption. For most of the world’s population, animal-derived foods are not available, and fortification iron is not yet widely distributed. In the vegetable category, the staples rice, maize, wheat, and beans have either moderate or poor iron availability . There are two major chemical forms (Fe2+ Fe3+) of iron in a diet, and each is absorbed by a different mechanisms. Heme, containing iron in a porphyrin ring structure is found in hemoglobin and myoglobin and accounts for nearly 40% of the iron present in animal tissue, including fish and poultry . Nonheme iron is present in foods of vegetable origin and also accounts for the remaining 60% iron in animal tissue. Other sources of nonheme iron are compounds added to fortify the diet with additional iron above its endogenous level. The most common sources are soluble iron salts or small-particle elemental iron. When taken without food, ferrous salts are better absorbed than ferric forms . This is probably related to the fact that ferric iron is insoluble in aqueous solution above pH 3, whereas the majority of ferrous iron remains soluble at pH 8.
Iron is a vital element in the body. It is also toxic when consumed in excess. Hence, its effect in the body is like a two-edged sword. Iron deficiency doesn’t always result in anemia, but it may cause other health problems such as lethargy or a weakened immune system. Iron deficiency occurs when the diet does not include enough iron rich foods, if there is blood loss, or if there is an increased need for iron during adolescence and pregnancy. When the body does not get enough iron, it cannot make enough red blood cells to carry adequate oxygen throughout the body. This condition of having too few red blood cells is called anemia. To prevent this diseases adequate intake of iron should be encouraged.
You may pump iron at the gym a few times a week, but your body pumps it continuously through the bloodstream every day. Iron is needed to make hemoglobin, a part of red blood cells that acts like a taxicab for oxygen and carbon dioxide. It picks up oxygen in the lungs, drives it through the bloodstream and drops it off in tissues including the skin and muscles. Then, it picks up carbon dioxide and drives it back to the lungs where it’s exhaled.
If the body doesn’t absorb its needed amount of iron, it becomes iron deficient. Symptoms appear only when iron deficiency has progressed to iron deficiency anemia, a condition in which the body’s iron stores are so low that not enough normal red blood cells can be made to carry oxygen efficiently. Iron deficiency is one of the most common nutritional deficiencies and the leading cause of anemia in the United States.
- Pale skin and fingernails
- Glossitis (inflamed tongue)
Sources of Iron
The body absorbs two to three times more iron from animal sources than from plants. Some of the best animal sources of iron are:
- Lean beef
Although you absorb less of the iron in plants, every bite counts, and adding a source of vitamin C to vegetarian sources of iron will enhance absorption. Some of the best plant sources of iron are:
- Beans and lentils
- Baked potatoes
- Dark green leafy vegetables such as spinach
- Fortified breakfast cereals
- Whole-grain and enriched breads
The following populations are at a higher risk for developing iron deficiency.
Women Who Are Pregnant: Increased blood volume requires more iron to drive oxygen to the baby and growing reproductive organs. Consult your doctor or registered dietitian nutritionist before taking an iron supplement.
Young Children: Babies store enough iron for the first six months of life. After six months, their iron needs increase. Breast milk and iron-fortified infant formula can supply the amount of iron not met by solids. Cow’s milk is a poor source of iron. When children drink too much milk, they crowd out other foods and may develop “milk anemia.” The American Academy of Pediatrics recommends no cow’s milk until after one year, at which point it should be limited to no more than 4 cups per day.
Adolescent Girls: Their often inconsistent or restricted diets — combined with rapid growth — put adolescent girls at risk.
Women of Childbearing Age: Women with excessively heavy menstrual periods may develop iron deficiency.
How to Prevent Iron Deficiency
Eat a balanced, healthy diet that includes good sources of iron to prevent any deficiencies. Combine vegetarian sources of iron with vitamin C in the same meal. For example: a bell pepper-bean salad, spinach with lemon juice, or fortified cereal and berries.
If treatment for iron deficiency is needed, a healthcare provider will assess iron status and determine the exact form of treatment — which may include changes in diet or taking supplements.
If you eat a vegan or vegetarian diet, or if you’re just aiming to keep your iron levels up, you probably know some of the many vegetables, fruits and grains that are good sources of iron. But did you know that not all iron is the same, and that some foods actually make it harder for your body to absorb iron?
If this is news to you, the folks at Stanford Blood Center have a how-to checklist that will help your body get the most iron out of your diet so you can stay healthy and have enough iron in reserve to donate blood to someone in need.
As the Stanford Blood Center blog explains, there are two types of iron: heme and non-heme. Heme iron is found in animal products and is generally easier for the body to absorb. Non-heme iron in found in vegan foods and is not as easily absorbed.
Iron deficiency anemia occurs when your body doesn’t have enough iron to make hemoglobin — the part of red blood cells that bind and carry oxygen in your blood. As the blog explains, “a vegetarian or vegan diet can make it difficult to keep your iron levels high – but contrary to popular belief, this is because of the type of iron consumed, not simply the amount.”
So, what should you eat? Here are some examples of foods with the highest amount of non-heme iron per serving:
- Whole wheat breads, cereals, pastas, quinoa and oatmeal
- Cooked spinach and cooked mushrooms
- Baked potato
- Legumes, soybeans, tofu and lentils
Pairing high-iron foods with ingredients that are high in vitamin C will enhance your body’s ability to absorb iron. Some examples of nosh that’s high in vitamin C are:
- Citrus fruits and citrus juice
- Red or green bell pepper
- Kiwi, strawberries, tomatoes, cantaloupe and papaya
Conversely, some foods can actually hinder your body’s ability to absorb iron as well, including:
- Coffee, tea (even decaffeinated) and soda
- Dairy products and calcium supplements
- Foods high in dietary fiber
- Wine and beer
If you still need a bit more iron, you can try iron supplements and even cast iron cookware, which transmits iron to food while it’s heating. Fun fact: In 2008, Christopher Charles, PhD, and his colleagues investigated ways to treat iron deficiency anemia in Cambodia by making iron ingots shaped like a fish — a symbol of luck, health, and happiness in local folklore — that could be placed in cooking pots as an inexpensive, reusable iron supplement.
Previously: Eating for good blood: Tips for boosting iron levels and hemoglobin
Photo by Getty Images
Anemia and Pregnancy
During the last half of pregnancy, your body makes more red blood cells in order to supply enough for you and your baby. Every red blood cell uses iron as its core. Iron cannot be made by your body and must be absorbed from the foods you eat.
Although iron is found in many foods, it is hard to absorb, making it difficult for your body to get enough to meet its needs during pregnancy. When you don’t have enough iron in your diet, you make fewer red blood cells, which is called anemia. Iron deficiency anemia is very common and is easy to correct.
Your body also needs a nutrient called folate to make healthy blood cells. Folate is easily absorbed and found in most green vegetables.
Causes of Anemia
- Poor intake of iron- and folate-rich foods
- Increased destruction of red blood cells that can occasionally occur during illness
Anemia Signs and Symptoms
Often, women with anemia don’t have specific symptoms. If anemia is severe, you may feel tired and weak.
- Eat iron-rich foods such as meat, chicken, fish, eggs, dried beans and fortified grains. The form of iron in meat products, called heme, is more easily absorbed than the iron in vegetables. If you are anemic and you ordinarily eat meat, increasing the amount of meat you consume is the easiest way to increase the iron your body receives.
- Eat foods high in folic acid, such as dried beans, dark green leafy vegetables, wheat germ and orange juice.
- Eat foods high in vitamin C, such as citrus fruits and fresh, raw vegetables.
- Cooking with cast iron pots can add up to 80 percent more iron to your food.
- Take your prenatal multivitamin and mineral pill which contains extra folate.
Because it is difficult to get enough iron from your diet, you may need to take an iron supplement. There usually is enough iron in your prenatal vitamin to prevent anemia, but your provider may prescribe an extra iron pill if you are anemic.
If the iron tablet upsets your stomach, take it with a small amount of food. Do not take your iron tablet with dairy products or calcium supplements.
The recommended dietary allowance (RDA) of iron during pregnancy is 30 milligrams. Here are some foods rich in iron.
Foods that provide .5 to 1.5 milligrams of iron:
- Chicken, 3 ounces
- Green peas, 1/2 cup
- Tomato juice, 6 ounces
- Broccoli, 1/2 cup
- Brussels sprouts, 1/2 cup cooked
- Whole wheat bread, 1 slice
- Dried apricots, 5 halves
- Raspberries, 1 cup
- Strawberries, 1 cup
Foods that provide 1.6 to 3 milligrams of iron:
- Sirloin steak, 3 ounces
- Roast beef, 3 ounces
- Lean hamburger, 3 ounces
- Baked potato with skin
- Kidney beans, 1/2 cup cooked
- Lima beans, 1/2 cup cooked
- Navy beans, 1/2 cup cooked
- Oatmeal, 1 cup cooked
- Raisins, 1/2 cup
Foods that provide 3 to 12 milligrams of iron:
- Clams, 4 large or 9 small
- Oysters, 6 medium
- Spinach, 1/2 cup cooked
- Fortified cereal, 1 cup
Additional sources of iron:
- All kinds of liver (except fish) — however, liver should not be eaten more than once a week
- Lean beef, veal, pork or lamb
- Greens, all kinds
- Soy bean flour
- Enriched pastas
- Unrefined sugars, such as molasses
5 Tips for Preventing Iron Deficiency
By Ashley Leone, RD
Choose Iron Rich Foods
Perhaps your diet has changed. Or you’ve entered into a life event that has you needing more iron. Or maybe you need more iron than most people. Whatever the reason for your deficiency it is crucial to check your diet for its iron content.
Omnivores and vegetarians alike can meet their Recommended Dietary Allowance (RDA) for iron by choosing wisely. Did you know there are two forms of iron in food? There is heme iron and non-heme iron. What’s the difference? Let’s take a look.
- Animal foods like red meat, poultry, and organ meats contain heme iron.
- Our body easily absorbs heme iron.
- Plant sources of iron contain non-heme iron.
- Beans, lentils, nuts, dark green leafy vegetables, tofu, tempeh, Cream of Wheat, and blackstrap molasses are sources of iron. Interestingly, grain products are fortified with iron in Canada and are another source of iron.
- Our body poorly absorbs non-heme iron. Improve your absorption of this form of iron by combining it with certain foods. We’ll talk more about this later.
Limit Food Interactions
Certain substances reduce our absorption of iron. For those who eat a mixed diet and have good iron stores, these interactions may be less important to consider. But, for those struggling to treat or prevent iron deficiency, substances that limit iron absorption are a concern. For these people, it is wise to limit foods that hinder iron absorption during their high iron meals.
Food interactions that may affect iron absorption include the following:
- Chocolate, tea, and dark green leafy vegetables contain oxalates.
- Oxalates impair the absorption of non-heme iron.
- Eat these foods separately from high iron foods.
- Tea, coffee, and cocoa contain polyphenols and hinder iron absorption.
- Similar to oxalates, eat or drink polyphenol-containing foods one or two hours before or after your iron rich meal.
- Soy foods, whole-wheat flours, walnuts, dried beans and lentils and sesame seeds are sources of phytates. Phytates may impair iron absorption by 50 to 60%.
- Dairy products, fortified soy products, almonds and dark green leafy vegetables are sources of calcium.
- Calcium hinders both heme and non-heme iron absorption.
- When you take a calcium supplement, take it between meals to limit this interaction. Speak with your pharmacist to ensure appropriate timing.
Harness the Power of Food Combinations
While non-heme iron is not well absorbed, combining it with certain foods and using good strategies can improve its absorption.
- Heme iron enhances the absorption of non-heme iron.
- The reason for this enhancement is not well known, but for those non-vegetarians out there this means that eating meat with beans is a recipe for better iron absorption. This combination makes Chilli con Carne a dish that is jam packed with iron. Try our Chilli con Carne recipe!
- Eating foods rich in vitamin C along with your high iron food will enhance the absorption of iron.
- This a fantastic idea when choosing predominantly non-heme iron sources.
- An example of this approach might be to have an orange along with your breakfast cereal. Or, you can check out this vegan recipe from our blog.
- Beta-carotene is an antioxidant found in yellow and red-coloured fruit and vegetables, like carrots.
- Carotenoids can improve non-heme iron absorption. Think of adding brightly coloured vegetables to your next veggie stir fry with tortilla shells.
- Bread, grains, dairy, fruit, and vegetables contain carbohydrates. Carbohydrates include starches, fibre and sugar.
- The Framingham Heart Study found that participants who ate fruit with their iron supplements had higher levels of iron than those who did not. The thinking is that the natural sugar in fruit enhances iron absorption.
Time Your High Iron Meals
Eat your high iron meals when they are best absorbed. This strategy is most important for people with low levels of iron and is less important for those with normal iron stores.
Eat your iron rich foods:
Separately from Oxalates, Polyphenols and Phytates
- Avoid eating or drinking foods that are high in oxalates, polyphenols or phytates along with your dietary source of iron.
- For example, avoid drinking tea and coffee at the same time as you eat your iron fortified breakfast cereal. Wait a couple of hours before enjoying your coffee.
Separately from Exercise
- Eat your highest iron meal opposite from when you exercise. If you are active in the morning, then your dinner should be high iron. If you are active in the evening, plan your high iron foods for the morning.
- This practice is important because exercise stimulates the release of a hormone that signals your body to reduce iron absorption.
Together with Heme Iron and Vitamin C
- Have a high vitamin C food with your breakfast. Vitamin C enhances non-heme iron absorption.
- Choose a grilled steak with your roasted beet and legume salad. Heme iron improves non-heme iron absorption.
Smart Iron Supplementation
Your doctor will try and find out what caused your iron deficiency. Sometimes there is a medical reason and sometimes diet is to blame. Even so, iron deficiency is not easily corrected by nutrition alone. You may need to supplement your iron.
There are a few routes of iron supplementation. Your doctor chooses your iron supplement based on how severe your deficiency is and your expected compliance. Also, some regions will consider supplement availability and cost.
Most often, iron supplements are prescribed in tablet form but are also available in liquid or parenteral (IV) form. You take these iron supplements until your deficiency has resolved and then you stop. High doses of supplements commonly cause black stool, nausea, and constipation. Consequently, many people stop taking iron supplements before they should. Even so, this route best treats severe iron deficiency. It is possible to take too much iron. Consult your doctor and pharmacist before taking iron supplements.
Lucky Iron Fish
The Lucky Iron Fish is a new and novel form of supplementation. The Lucky Iron Fish is a fish-shaped iron cooking tool that you place in 1 L (4 cups) of water with 2-3 drops of citrus (like lemon juice) and boil for 10 minutes. The Lucky Iron Fish releases a safe and gentle dose of iron into the boiling water, without the side effects found in conventional supplements. As a result, people are more likely to use the Lucky Iron Fish to manage their iron deficiency.
Iron deficiency is a common nutritional problem, but you don’t have to feel overwhelmed. Try these five tips to tackle and alleviate your iron deficiency. For more information about iron deficiency anemia and what Lucky Iron Fish Enterprise is doing to conquer iron deficiency, .