What does iron do?
Iron is an essential mineral that plays several important roles in the body. It is a component of hemoglobin, the protein in red blood cells that carries oxygen from the lungs to the body’s tissues. Iron is also a component of myoglobin, a protein that helps muscle cells store and use oxygen.
In addition to its role in oxygen transport, iron is also involved in several other important processes in the body. It is necessary for the production of collagen, a protein that helps to form connective tissues such as skin, tendons, and ligaments.
Iron is also needed for the production of certain hormones and neurotransmitters, as well as for the proper function of the immune system.
Symptoms of iron deficiency
Iron deficiency is a condition that occurs when the body does not have enough iron. The symptoms of iron deficiency can vary, but may include:
- Fatigue and weakness
- Difficulty maintaining body temperature
- Difficulty concentrating
- Headaches
- Pale skin
- Dizziness
- Chest pain
- Rapid heartbeat
- Shortness of breath
If left untreated, iron deficiency can lead to a condition called iron-deficiency anemia, which can cause further health problems. These may include:
- Heart problems: Iron deficiency can lead to an enlarged heart and other heart problems.
- Infections: Iron is necessary for the proper function of the immune system, so iron deficiency can make a person more susceptible to infections.
- Pregnancy complications: Iron deficiency during pregnancy can cause problems such as premature birth and low birth weight.
- Growth and developmental problems in children: Iron is necessary for proper growth and development, so iron deficiency can lead to problems such as delayed growth and poor cognitive development in children.
Symptoms of too much iron
Too much iron in the body, a condition known as iron overload or hemochromatosis, can lead to a number of symptoms and health problems. Some common symptoms of iron overload include joint pain, fatigue, weight loss, abdominal pain, and a general feeling of ill health.
Over time, iron overload can damage the liver, heart, and other organs, leading to potentially serious health problems such as liver disease, heart failure, and diabetes.
Who needs iron?
Recommended Daily Allowances
The Recommended Dietary Allowance (RDA) for iron varies depending on a number of factors, including a person’s age and gender. For adult men, the RDA for iron is 8 milligrams per day, while for adult women, the RDA is 18 milligrams per day. However, pregnant women have an increased need for iron, and the RDA for pregnant women is 27 milligrams per day.
It is important to note that the RDAs for iron are based on the average requirements of a healthy population and may not be appropriate for individuals with special dietary needs or medical conditions. Individuals should speak with a healthcare provider to determine their specific iron needs.
People at risk of low iron
There are certain groups of people who may require more iron or iron supplements due to their increased iron needs or decreased iron absorption. These include:
- Pregnant women: Pregnant women need more iron to support the growth and development of their fetus.
- Women with heavy menstrual bleeding: Women who experience heavy menstrual bleeding may lose more iron than women who have normal menstrual periods.
- Infants and young children: Infants and young children need iron for growth and development.
- Vegetarians and vegans: Plant-based sources of iron are not as easily absorbed as iron from animal sources, so vegetarians and vegans may need more iron in their diet or may need to take iron supplements.
- People with gastrointestinal disorders: Certain gastrointestinal disorders can affect iron absorption, such as celiac disease and inflammatory bowel disease.
Dietary vs supplemental iron
There are two main ways to improve iron levels in the body: through diet and through supplements.
Dietary iron is iron that is obtained from food sources. One benefit of using dietary iron to improve iron levels is that it is natural and generally safe. Consuming a balanced diet that includes iron-rich foods is generally considered a healthy practice, and it can provide other nutrients in addition to iron.
However, there are also some downsides to using dietary iron to improve iron levels. For one, it can be difficult to get enough iron from food alone, especially if a person has a poor appetite or has a condition that interferes with their ability to absorb iron from food.
Also, the low bioavailability of iron in certain foods like non-animal sources makes it more difficult to increase iron levels from vegetarian sources.
Supplemental iron, on the other hand, is iron that is taken in the form of a pill or other supplement. These supplements are available over-the-counter or by prescription, depending on the specific product.
One benefit of using supplemental iron to improve iron levels is that it can provide a concentrated dose of iron. This can be helpful for people who have difficulty getting enough iron from their diet, or for those who need to more quickly increase their iron levels for medical reasons.
However, there are also some downsides to using supplemental iron. For one, iron supplements can cause side effects such as stomach upset and constipation. In addition, taking too much iron can be dangerous, so it is important to follow a healthcare provider’s instructions when taking these supplements.
Dietary iron
There are number of dietary sources of iron. How well your body is able to use those sources depends on how bioavailable the iron is. Iron bioavailability refers to the percentage of iron in the food that is absorbed by the body. A food can contain a lot of iron, but if it’s not bioavailable, your body won’t be able to use it anyways:
- Animal sources of iron (heme iron) tend to be more bioavailable, and easier for the body to absorb.
- Plant sources of iron (non-heme iron) tend to be less bioavailable, and harder to extract for the body to use.
One way to increase the absorption of non-heme iron, is to take a source of Vitamin C with it. This slightly increases the bioavailability of non-heme sources of iron.
Animal sources
Most animal sources of iron have relatively high bioavailability, with red meats having some of the highest concentrations of iron. Eggs and dairy tend to have lower concentrations of iron, with poorer bioavailability.
| Animal source | Iron (mg) | Bioavailability (%) |
|---|---|---|
| Beef liver | 6.5 | 15-35 |
| Beef | 2.9 | 4-30 |
| Lamb | 2.2 | 4-30 |
| Veal | 1.4 | 4-30 |
| Ham | 1.2 | 4-30 |
| Eggs (whole) | 1.2 | 5-15 |
| Turkey | 0.9 | 4-30 |
| Chicken | 0.9 | 4-30 |
| Pork | 0.9 | 4-30 |
| Egg white | 0.1 | 5-15 |
| Milk (2%) | 0.1 | 5-15 |
Seafood sources
Clams, oysters, and mussels have some of the highest concentrations of iron. In general, seafood also has good sources of iron, making them good iron sources for pescatarians.
| Seafood | Iron (mg) | Bioavailability (%) |
|---|---|---|
| Clams | 28.8 | 2-15 |
| Oysters | 7.8 | 2-15 |
| Mussels | 6.7 | 2-15 |
| Sardines | 2.9 | 7-30 |
| Shrimp | 2.6 | 7-30 |
| Tuna | 1.0 | 7-30 |
| Haddock | 0.9 | 7-30 |
| Salmon | 0.7 | 7-30 |
Nuts, seeds, and legumes
Nuts, seeds, and legumes also contain various levels of iron. Although they suffer from lower bioavailability, they do contain a good amount of other nutrients.
| Grain | Iron (mg) | Bioavailability (%) |
|---|---|---|
| Cashews | 6.7 | 2-13 |
| Pumpkin seeds | 4.2 | 2-15 |
| Lentils | 3.3 | 6-8 |
| Chickpeas | 2.9 | 5-6 |
| Tofu | 2.7 | 5-13 |
| Beans | 2.5 | 2-9 |
| Flaxseeds | 2.2 | 2-15 |
| Sesame seeds | 2.1 | 2-15 |
| Hemp seeds | 2.1 | 2-10 |
| Sunflower seeds | 1.5 | 2-9 |
| Peas | 1.5 | 5-12 |
| String beans | 0.8 | 5-12 |
Grains
A lot of grains also contain iron. However the bioavailability is quite low, meaning you may need to eat quite a bit of them to get enough iron. Despite having a good amount of fiber, grains are also high in carbs, which may be difficult for low carb diets.
| Grain | Iron (mg) | Bioavailability (%) |
|---|---|---|
| Amaranth | 7.6 | 2-15 |
| Quinoa | 4.6 | 2-15 |
| Tomato paste | 3.9 | 2-10 |
| Oats | 3.7 | 5-12 |
| Spelt | 3.2 | 2-10 |
| Barley | 2.5 | 2-10 |
| White bread | 1.4 | 5-15 |
| Whole wheat bread | 1.4 | 5-15 |
Vegetables
Leafy greens and tomato paste have some of the higher concentrations of iron, but much of is not as bioavailable as other sources. This makes getting iron from these sources more difficult.
| Vegetable | Iron (mg) | Bioavailability (%) |
|---|---|---|
| Tomato paste | 3.9 | 2-10 |
| Dandelion greens | 3.1 | 2-10 |
| Spinach | 2.7 | 2-10 |
| Swiss chard | 1.8 | 2-10 |
| Kale | 1.5 | 2-10 |
| Beets | 0.8 | 2-10 |
| Broccoli | 0.7 | 5-12 |
| Collard greens | 0.4 | 2-10 |
Other plant sources
There are sources of iron in food that are appropriate for vegetarians or vegans. Fruits and dried fruits are some of the lowest sources, although they do provide small amounts.
For the most part, these sources won’t be a primary source of iron, since many of them are high in sugar, meaning you’ll be significantly increasing your sugar content if you try to get iron primarily from these sources.
| Food | Iron (mg) | Bioavailability (%) |
|---|---|---|
| Dark Chocolate | 8.0 | 2-10 |
| Blackstrap Molasses | 4.7 | 7 |
| Figs | 3.3 | 3 |
| Dried Apricots | 2.7 | 2-3 |
| Dried Peaches | 2.5 | 2-3 |
| Prunes | 2.4 | 2-3 |
| Raisins | 1.9 | 2-3 |
| Maple Syrup | 0.2 | 5 |
Supplements
Supplements are often a more consistent and faster way to improve iron status. Some common forms include:
- Ferrous sulfate is one of the most commonly used iron supplements. It is well absorbed by the body, making it highly bioavailable. It is also relatively inexpensive and available over-the-counter, making it a cost-effective option. However, it can cause gastrointestinal side effects such as nausea, constipation, and abdominal pain in some people.
- Ferrous gluconate is another form of iron supplement that is commonly used. It is less likely to cause gastrointestinal side effects than ferrous sulfate, but it is also slightly less bioavailable. It is also less expensive than some other forms of iron supplements and available over-the-counter.
- Ferric citrate is highly bioavailable and well-tolerated by most people. It is less likely to cause gastrointestinal side effects than ferrous sulfate, but it may be more expensive and is only available by prescription.
- Ferrous fumarate is also well-absorbed by the body and less likely to cause gastrointestinal side effects. It is generally less expensive than ferric citrate, but also available in over-the-counter and prescription forms.
- Iron polysaccharide complex is made up of iron molecules bound to complex carbohydrates, which makes it less likely to cause gastrointestinal side effects. It is also highly bioavailable and available over-the-counter, although is not very common.
- Iron bisglycinate is a chelated form of iron, meaning that the iron molecules are bound to amino acids, which improves its absorption and makes it less likely to cause gastrointestinal side effects. It is generally more expensive than other forms of iron supplements and is available over-the-counter.
Improving absorption
Iron supplements are often harder to increase in the body than other minerals because the body’s ability to absorb and utilize iron is tightly regulated and limited.
Unlike many other minerals, such as calcium or magnesium, the body does not have an efficient mechanism for excreting excess iron.
Therefore, once iron is absorbed, it tends to accumulate in the body, which can be toxic in high amounts.
That being said, there are a few other supplements that can help to improve their absorption, including:
- Vitamin C: Vitamin C can increase the absorption of non-heme iron (the type of iron found in plant-based foods and supplements) by reducing the iron molecules into a form that is more easily absorbed by the body.
- Vitamin A: Vitamin A can help the body absorb and utilize iron more efficiently.
Other ways
A few other ways have been used to increase iron. Many of these methods are not as effective or consistent as improving iron levels through dietary and supplemental means, however can provide small amounts of iron:
- Using an iron pot or pan to cook food. Iron can leach into food that is cooked in iron pots or pans, providing a small amount of dietary iron.
- Using topical iron products. Some patches, skin creams, and ointments contain iron and can be applied to the skin to help increase iron levels.
Injections
Iron dextran and ferric gluconate are two forms of injectable iron supplements. Iron dextran is a complex of iron and dextran that is slowly released into the bloodstream, providing a sustained supply of iron over several days. Ferric gluconate, on the other hand, is a water-soluble form of iron that is quickly absorbed by the body. Both forms of injectable iron are commonly used to treat iron deficiency anemia.
These forms are typically given by a healthcare provider, and are typically used when oral iron supplements are not effective or well-tolerated. This can be due to a variety of reasons, such as poor absorption of iron from the gastrointestinal tract, or side effects such as nausea and stomach upset.
Injectable iron can bypass the gastrointestinal tract and deliver a concentrated dose of iron directly into the bloodstream, making it a more effective option for some people. Injectable iron is also often used in situations where a rapid increase in iron levels is needed, such as in severe anemia or during pregnancy.
How long does it take?
The time it takes to improve iron status can vary depending on the individual’s initial iron levels, how much iron they take, and how well their body is able to absorb the iron. In general, it can take several weeks to a few months to see an improvement in iron levels. So it’s not going to be a quick fix.
For mild iron deficiency anemia, it may take around 3-6 months of taking iron supplements to reach normal iron levels. For more severe cases, it may take longer, up to 6-12 months. It’s important to take iron supplements as prescribed by a healthcare professional and to continue taking them until iron levels have returned to normal.
Keep in mind that the body has limited capacity to absorb and use iron. Unlike other minerals, the body cannot get rid of excess iron easily, which can be harmful. When we consume too much iron, it can build up in the body and cause toxicity. Therefore, it’s important to be careful when taking iron supplements and to ensure that iron intake is sufficient but not excessive.
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