Functions of Iron
The trace mineral, iron, performs many roles in our bodies. In our red blood cells iron is required to form haemoglobin which transports oxygen to every cell in our body increasing energy levels. Iron, therefore, contributes to the reduction of tiredness and fatigue. It also helps metabolise proteins, boosts our immunity, and helps maintain brain and endocrine (hormonal) function.
It’s thought millions of the UK population suffer from mild anaemia, most often caused by an inadequate intake of nutrients such as iron, folate or vitamin B12. Iron deficiency leads to anaemia, and it is regarded as the most common nutritional deficiency in the U.S., where about 10 percent of all women are considered iron deficient. There are an estimated 2 billion iron deficient people worldwide.
Iron deficiency is the result of unhealthy refined diet, avoiding high in iron plant foods, use of stimulants, and other factors including poor absorption and heavy menstruation. Also, regular consumption of soda, cow’s milk, and chocolate contribute to iron deficiency.
It is a very well-established fact that both black and green tee as well as coffee (especially when ingested during meals and up to 2 hours after meals) lead to iron deficiency. In England alone people manage to get through an amazing 235 million cups coffee and tea every day. Both tea and coffee contain tannins which are also present in wine, beer and some other foods.
These tannins adversely affect iron availability, which could lead to iron deficiency anaemia. One study has shown that tea consumption may reduce iron absorption by as much as 60% and coffee reduces its uptake by 50%!
Another study showed just 100 mg of tannins inhibited absorption by almost 90%, whereas additional research concluded we would have to drink 3 strong cups of tea or coffee a day to have this effect. Apart from tannins also caffeine in coffee, black, tea, green tea and other products binds to about 6% of the iron from a meal.
Unfortunately, also green tea has similar effect as coffee and black tea due to high content of tannins. There are many examples of individuals who developed iron deficiency due to regular green tea drinking, here is one of them: “I have been drinking green teas every day for the past few years.
Two years ago, I was diagnosed with an iron deficiency and to date I have had several blood transfusions and numerous treatments of ferrite through IV. I have had numerous medical tests, bone marrow, colonoscopy, capsule endoscopy etc. And have not found the cause. Yesterday a friend who had similar problems told me she had been admitted to the Mayo Clinic some months ago and the team their discovered her problem was excessive drinking of green tea.”
Symptoms of iron deficiency anaemia may include the following: fatigue, weakness, pale skin, tingling sensation in the legs, poor memory, dizziness, hair loss, tongue swelling or soreness, depression, anxiety, and breathlessness. Chronic lack of iron may also contribute to the following:Fibromyalgia, inflammatory bowel disease, hypothyroidism, attention deficit hyperactivity disorder, Parkinson’s disease, neurodegenerative conditions, celiac disease, restless leg syndrome, muscle weakness, and decline in motor skills.
Best Dietary Sources of IronThe following are regarded as the most iron-dense plant foods:
Chlorella is one of the most nutrient-dense foods in the world. A one ounce (about 2 tablespoons) serving of this single-celled green algae supplies us with a whopping 37 milligrams of iron, or 200 percent of our recommended daily intake!
Spirulina contains a considerably lower 8 milligrams of iron than chlorella, but it exceeds chlorella in other areas. For this reason, many experts recommended consuming chlorella and spirulina together to maximize nutrient intake and remove practically any possible nutrient deficiency.
Some sources maintain moringa leaf to be up to 25 times higher in iron than spinach.
Goji berries – a mere quarter-cup of these red, tangy berries provide us with all the iron we need for the day.
Blackstrap molasses derived from the sugar cane plant, whose roots tap into the deepest (and most mineral-rich) parts of the soil. Two tablespoons of blackstrap contain 15 percent of our RDI for iron.
Spinach, Swiss chard, kale and broccoli are the most iron-rich greens. A cup of cooked or raw spinach may contain 6-7 mg of iron.
Just one cup of cooked organic soybeans contains 9 mg of natural organic iron! Remember that unlike GMO organic soya beans and soya product should be regarded as perfectly safe and one of the healthiest and nutrient-dense foods. One cup of cooked white beans or lentils contains 6.5 milligrams of iron, kidney beans: 5.2 milligrams; chickpeas: 4.7 mg.
In contrast, 3 ounces of a duck contain 3.5 milligrams of iron, a can of sardines: 2.7 milligrams, 3 ounces of grass-fed beef: 2 mg, and 3 ounces of lamb (19): 1 mg. Even liver doesn’t seem to be a higher source of iron as 3.5-ounce (100-gram) serving of beef liver contains 6.5 mg of iron.
- Whole milk contains less iron than any other type of milk, with just .07 mg per 1-cup serving. Organic unsweetened soya milk is much better source of iron.
Contrary to the popular view, animal foods do not seem to be higher in iron than mentioned above plant sources. In addition, plant foods usually contain significant concentrations of vitamin C which doubles the absorption of iron. Vitamin C is not found in useful amounts in cooked animal foods.
Another important fact is that, unlike heme iron found in animal foods, non-heme iron in plant sources does not increase risk of cancer, diabetes, stroke, inflammation and heart disease (see quote by Dr. Greger below).
Other valuable plant sources of iron are whole grains, split peas, dried fruits, nuts, and seeds. Unlike non-heme iron from plants, the heme iron found in animal foods increases risk of heart attack, stroke, cancer and diabetes.
According to Dr. Michael Greger M.D. “It is commonly thought that those who eat plant-based diets may be more prone to iron deficiency, but it turns out that they’re no more likely to suffer from iron deficiency anaemia than anybody else. This may be because not only do those eating meat-free diets tend to get more fibre, magnesium, and vitamins like A, C, and E, but they also get more iron. The iron found predominantly in plants is non-heme iron, which isn’t absorbed as well as the heme iron found in blood and muscle, but this may be a good thing.
Avoidance of heme iron may be one of the key elements of plant-based protection against metabolic syndrome and may also be beneficial in lowering the risk from other chronic diseases such as heart disease. The data linking coronary heart disease and the intake of iron, in general, has been mixed.
This inconsistency of evidence may be because of where the iron comes from. Most of the total dietary iron is non-heme iron, coming mostly from plants. So, total iron intake is associated with lower heart disease risk, but ron intake from meat is associated with a significantly higher risk for heart diseases.
This is thought to be because iron can act as a pro-oxidant, contributing to the development of atherosclerosis by oxidizing cholesterol with free radicals. The risk has been quantified as a 27% increase in coronary heart disease risk for every 1 milligram of heme iron consumed daily. The same has been found for stroke risk. The studies on iron intake and stroke have had conflicting results, but that may be because they had never separated out heme iron from non-heme iron… until now.
Researchers found that the intake of meat (heme) iron, but not plant (non-heme) iron, was associated with an increased risk of stroke. The researchers also found that higher intake of heme iron—but not total or plant (non-heme) iron—was significantly associated with greater risk for type 2 diabetes. There may be a 16% increase in risk for type 2 diabetes for every 1 milligram of heme iron consumed daily.
The same has also been found for cancer, with up to 12% increased risk for every milligram of daily heme iron exposure. In fact, we can tell how much meat someone is eating by looking at their tumours. To characterize the mechanisms underlying meat-related lung cancer development, researchers asked lung cancer patients how much meat they ate and examined the gene expression patterns in their tumours.
They identified a signature pattern of heme-related gene expression. Although they looked specifically at lung cancer, they expect these meat-related gene expression changes may occur in other cancers as well.” (1).
Heme VS. Non-Heme Forms of Iron
There are two forms of dietary iron, heme iron and non-heme iron. Heme iron is bound to haemoglobin (the oxygen transporting protein in red blood cells) whereas the non-heme iron is not bound to haemoglobin. Plants and iron-fortified foods contain only non-heme iron, whereas meat, seafood, and poultry contain both heme and non-heme iron. Heme iron is more efficiently absorbed form of iron. It is estimated that around 15 to 35 % of heme iron is absorbed, compared to 5 to 20 % of non-heme iron. Unfortunately, although it is true that heme iron, the type found predominantly in blood and muscle, is absorbed better than the non-heme iron present in plants, yet the heme iron may increase the risk of cancer, stroke, heart disease, and metabolic syndrome (see quote below by DR. Greger).
Ferrous VS. Ferric Forms of Iron
There are ferrous and ferric iron forms. Common ferrous preparations include ferrous succinate, ferrous bisglycinate, ferrous fumarate, ferrous sulphate, ferrous gluconate, and ferrous lactate. Among the ferric preparations ferric citrate and ferric sulphate are most used. Because of its higher solubility, ferrous iron in dietary supplements is more bioavailable than ferric iron. Iron supplements contain different amounts of elemental iron, which is the amount of iron that is absorbed in our body, depending on which form of iron is used in the supplement. For example, ferrous gluconate contains 12 % elemental iron, ferrous sulphate contains 20 % elemental iron, while ferrous fumarate, ferrous succinate, and ferrous bisglycinate contain over 30 % of elemental iron. Elemental iron should be listed in the supplement label, so consumers do not need to calculate the amount of iron supplied by various forms of iron supplements.
Types of Ferrous Iron
Iron bisglycinate (ferrous form of iron called ferrous bisglycinate) is 33% elemental iron. It is regarded as the best iron form due to high bioavailability and because it shouldn’t cause gastric problems (including constipation). Iron bisglycinate is a chelated form of non-haem iron (consists of ferrous iron combined with an amino acid) that passes through the stomach and small intestine without breaking apart.
It has been shown to be more effectively absorbed than other types of iron chelate. Iron bisglycinate should be combined with glycine and vitamin C for optimal absorption, to prevent the gastrointestinal side effects. According to the research, iron absorption was higher from ferrous bisglycinate than from ferrous sulphate or ferric trisglycinate and ferrous bisglycinate was an effective and safe source of iron.
Ferrous bisglycinate 25 mg iron is as bioavailable as Ferrous fumarate is 33% elemental iron; ferrous fumarate is an inexpensive form of iron with tolerable adverse effects, and it increases iron stores significantly. Ferrous bisglycinate and carbonyl iron show equal efficacy as ferrous fumarate in increasing Hb and produced less adverse effects than ferrous fumarate but cost more. Ferrous fumarate is found, for example, in Haemovit Plus which contains 47mg of highly absorbable ferrous fumarate per capsule.
Haemovit Plus, however, might be too high in iron for an average person and should be recommended rather for individuals with already diagnosed iron deficiency or women with heavy menstruation as too much iron in the body leads to overproduction of free radicals and other side effects. As far as bioavailability and tolerability is concerned ferrous fumarate is superior to ferric forms as they have few times lower bioavailability.
Ferrous sulfate monohydrate is 33% elemental iron while ferrous sulfate heptahydrate is 20% elemental iron. Ferrous sulfate, can cause gastrointestinal side effects, including nausea, vomiting, constipation, and diarrhoea. Ferrous gluconate is 12% elemental iron. Ferrous gluconate is found in Iron Formula (HealthAid) which contains 17mg per 3 tablets).
Types of Ferric Iron
Iron Citrate (ferric citrate) has lower bioavailability than the ferrous forms, but it is the best option among 3 different ferric irons as it doesn’t cause toxicity. Ferric Ammonium Citrate (Iron citrate) is found in Haemovit Gold (HealthAid).
Recommended Daily Intake of Iron
0 to 3 months: 2 mg
4 to 6 months: 4 mg
7 to 12 months: 8mg
Children 1 to 3 years: 9 mg
Children 4 to 8 years: 9 mg
Children 9 to 13: 8 mg
Women 19 to 50: 17 mg
Pregnant women: 25 mg
Lactating women: 10 mg
Women over 50: 10 mg
Men 19 to 60: 10 mg
Younger children need more iron than older children because iron is required for proper growth and cognitive development. It can be hard for them to get enough iron from their diet alone. Iron deficiency is seen most often between six months and three years of age due to rapid growth and inadequate intake of dietary iron. Infants and children are at a heightened risk for iron deficiency if they’re born prematurely, are given cow’s milk before their first year of life, and if they are formula-fed instead of breastfed.
Heavy menstruating women and women who are pregnant need more iron. Also, those who lost blood due to a recent surgery need iron supplements.
Overdosing of Iron and Toxicity
High doses of supplemental iron (50 mg/day or more) may cause gastrointestinal side effects, such as nausea, diarrhoea, vomiting, upset stomach and constipation. Iron supplements could be a double-edged sword. If we don’t get enough, we risk fatigue and other symptoms of iron anaemia; but if we ingest too much, we may increase risk of brain degeneration (such as Alzheimer’s), cancer, heart disease, stroke, diabetes, and several inflammatory conditions. Chronic excessive intake of iron may also contribute to the following:
Premature aging, anorexia, Grave’s disease, heart arrhythmia, liver damage and liver disease, or hemochromatosis.
Too much iron in the body can lead to the mentioned above problems because the human body doesn’t seem to have a mechanism to rid itself of excess iron. In excess iron works as a pro-oxidant, and therefore it can significantly increase the harmful free-radical activity.
For this reason, take only good quality iron supplements and make sure you don’t overdose it. Slowly working up to the full dose can limit these side effects, as can taking iron with food. However, taking iron with some foods and beverages limits the absorption of the iron, especially if you take it along with dairy products, tea, or coffee.
While ferrous sulphate is the most used type of iron supplement, switching to a different form of iron (such as bisglycinate) and lowering the daily dose may help prevent side effects.
In addition, if you want to prevent oxidative or radical effect of excess iron take Alpha lipoic acid (ALA) twice a day. According to the 2008 human study, “Lipoic acid and acetyl-carnitine reverse iron-induced oxidative stress.”
ALA is regarded as one of the most effective detoxification aids as it can reduce chemical toxicity in tissues and counteract subsequent oxidative stress changes. This benefit of ALA has been shown with regards to cyanate poisoning, ifosfamide (chemotherapy drug), and toxic mushroom poisoning.
ALA works as a chelator or remover of toxic minerals and heavy metals (such as lead or mercury) from our body. It is also able to chelate excess iron in our body. Iron can be also catalysed into a harmful activity by the certain drugs such as antibiotic gentamicin.
Combination of gentamicin and iron leads to the formation of dangerous free radicals. It means that Alpha lipoic acid has also the ability to disarm the harmful iron! (2).
Calcium might interfere with the absorption of iron. For this reason, some experts suggest that people take individual calcium and iron supplements at different times of the day. Vitamin C strongly enhances the absorption of non-heme iron by reducing dietary ferric iron to ferrous iron and forming an absorbable, iron-ascorbic acid complex. Organic acids such as citric, malic, tartaric, and lactic acid have some enhancing effects on non-heme iron absorption.
Do not take any kind of iron supplement if you have hemochromatosis and hemosiderosis. It is also suggested to avoid iron supplements in haemolytic anaemia such as sickle cell anaemia. Anaemia caused by sickle cell disease is not the same as the common iron deficiency anaemia. The problem isn’t the amount of iron, but the shape of the cells themselves. You don’t want to increase your haemoglobin too much and create more of a chance of a crisis. Therefore, in case of sickle cell anaemia you shouldn’t take iron supplements without seeking professional advice as they could be dangerous as because extra iron build up in the body can lead to liver damage and other problems mentioned above.
- Microcytic Anaemia (Iron Deficiency) | HealthAid
- Key Nutritional Deficiencies and How to Prevent Them | HealthAid
- Fairweather-Tait SJ, Wawer A, Gillings R, et al. Iron status in the elderly. Mech Ageing Dev 2014;136-137(100):22-28
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