Iron deficiency occurs when the body’s iron stores are too low. This interferes with the body’s ability to produce hemoglobin, a component of red blood cells that enables them to transport oxygen.
Causes of iron deficiency include blood loss, a lack of iron in your diet, or certain medical conditions. Symptoms include tiredness, weakness, poor concentration, and dry skin and nails. In some cases, iron deficiency anemia can develop and result in low blood pressure, heart palpitations, shortness of breath, and an increased risk for infections.
This article discusses the stages, causes, and symptoms of iron deficiency and iron deficiency anemia. It also suggests steps you can take to prevent this condition.
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Low Iron and Your Body
Iron is an important nutrient: It helps your body producehemoglobinand myoglobin, two proteins that carry oxygen in your blood. When you don't get enough iron, your cells don't get what they need to give you energy.
It takes a while to develop symptoms of iron deficiency anemia. When you don't get enough iron in your diet, your body can use stored and recycled iron to form new blood cells. When the iron supply begins to run out, symptoms will develop as your body slows the production of red blood cells.
Stages of Iron Deficiency
Iron deficiency occurs in three stages.
Stage 1: the body’s iron stores begin to be depleted. Your hemoglobin levels may still be normal, but serum ferritin levels are low.Ferritin is a protein that stores iron. You may feel run down and tired, although many people do not have any symptoms.
Stage 2: The body does not have enough iron to build new red blood cells. Instead, the body uses zinc. Blood work may still show normal hemoglobin levels, but transferrin saturation levels (a measure of how much iron is being held in the body) are low, and zinc protoporphyrin (ZPP), which helps use zinc In RBCs, is high. You may feel fatigued and dizzy at this stage, although you may not have any symptoms.
Stage 3: This stage is defined as iron deficiency anemia. In this stage, hemoglobin levels drop below the normal range:
- 12 to 15 g/dL for women
- 14 to 16.5 g/dL for men
At this stage, you will likely feel tired, weak, and short of breath when climbing stairs or exercising. You may also experience headaches, dizziness, and heart palpitations.
Iron Deficiency Causes
Low iron levels can be caused by a few different things, including:
Diet and Absorption
You can develop iron deficiency if you don't eat enough iron-containing foods or if you have trouble absorbing iron. Vegetarians and vegans may be more prone to iron deficiency, especially premenopausal females. This is because non-heme iron, the form found in plants, is not absorbed as well as heme iron, the form found in meat, poultry, and fish.
Some illnesses prevent the absorption of iron, including:
- Crohn's disease
- Celiac disease
- Cystic fibrosis
- Chronic pancreatitis
Weight loss surgeries may also lead to iron deficiency. Gastric bypass, for example, often involves the removal of sections of the stomach or intestine. This can interfere with iron absorption.
Phytic acid is an antioxidant found in legumes, rice, and grains. It can inhibit iron absorption, which may contribute to iron deficiency anemia.
Extra Iron Requirements
During pregnancy, you have greater blood volume. A developing fetus also needs oxygen-rich RBCs for energy. This is why you need more iron during pregnancy. If you're pregnant and not taking prenatal vitamins, you may fall short of this goal.
Actively growing bodies need extra iron to provide energy to developing cells. That's why it's also important for babies, children, and teens to get plenty of iron. Female athletes may also need additional iron.
Blood Loss
Normal or heavy menstrual bleeding can lead to iron deficiencyanemia. For this reason, females generally need more iron than males.
Medical conditions that cause chronic bleeding, especially when it's rapid, can lead to low blood volume and iron deficiency anemia.
These conditions include:
- Ulcers
- Hemorrhoids
- Polyps
- Colon cancer
In these cases, symptoms tend to be more severe.
Surgery, childbirth, or an injury can also cause excessive blood loss. After donating blood, you may also be a little low in RBCs for a few days. However, in healthy people who donate blood, RBC volume is usually corrected without noticeable symptoms.
Conditions Associated with Iron Deficiency
Some situations are associated with iron deficiency but don't cause it.
For example:
- Being underweight. Calories from any source do not affect iron absorption. Still, people who are underweight are often iron deficient because there isn't enough iron in their diet.
- Kidney disease. Erythropoietin is a hormone produced by the kidneys. It plays an important role in stimulating red blood cell production. You may need erythropoietin replacement to stimulate red blood cell production if you have kidney disease. Dialysis does not correct this hormone problem.
- Some cancers, especially those that involve white blood cells, are associated with low RBC levels. Leukemia and lymphoma, for example, can impair the production of RBCs. Most cancer treatments also suppress the production of RBCs. The lack of RBCs doesn't decrease iron levels, but it prevents the iron in the body from doing what it is meant to do.
Iron Deficiency Symptoms
If you have iron deficiency anemia, it can lead to a number of symptoms. They may progress quickly, or they may appear over weeks or months.
- Fatigue
- Weakness
- Problems with memory and thinking
- Feeling cold
- Headaches or dizziness
- Dry, brittle hair, skin, and nails
- Strange cravings for metal, dirt, paper, or starchy food, called pica
- Red, inflamed tongue, called glossitis
- Frequent infections
- Heart palpitations
- Shortness of breath
- Restless legs syndrome
Symptoms can come on quickly with severe iron deficiency or rapid blood loss. Symptoms of moderate iron deficiency may be slower to appear.
In some cases, iron deficiency leads to weight gain. Scientists think this can be due to fatigue, which causes you to be less active. Others suspect iron deficiency may slow your metabolism. Either way, research shows treating iron deficiency anemia helps to promote weight loss.
Complications
Extreme iron deficiency anemia can cause tachycardia or rapid heart rate. It can also cause low blood pressure. In children, extreme iron deficiency may contribute to learning and concentration problems.
Pregnant women who have an iron deficiency can have low energy. They also have an increased risk of low birth weight babies and premature birth.
Diagnosing Iron Deficiency
A complete blood count (CBC) is a blood test that counts your platelets andyour red and white blood cells. This test can only suggest iron deficiency anemia, because there are also other causes. Your healthcare provider will try to identify the cause based on your medical history and exam.
Tests to see if you have gastrointestinal (GI) bleeding may also be done. If your healthcare provider doesn't suspect GI blood loss, you may need to start a trial of iron supplements with close follow-up. If there is no improvement after a few weeks or if it's still unclear what is causing your anemia, you may need iron studies.
These blood tests usually measure:
- Serum ferritin
- Serum iron
- Serum transferrin
- Transferrin
If the cause still can't be found, bone marrow biopsy is the gold standard for diagnosis. During this procedure, a sample of bone marrow is taken using a hollow needle.
Physical Examination
For many conditions, a physical exam is the most important diagnostic tool. Symptoms of iron deficiency, though, don't usually develop until weeks or months after you have an abnormal blood test.
These late symptoms include:
- Pale skin
- Rapid heartbeat
- Low blood pressure while standing
This is why a physical exam usually can't identify an iron deficiency.
Follow-Up Testing
It's very important to find the cause of iron deficiency anemia. One of the first things many doctors do is look for occult blood loss. This is hidden or unnoticed blood loss. The most common cause is bleeding from the colon.
The first step toward identifying this cause is to look for blood in a stool sample. If there is no blood, your doctor may still order a colonoscopy or endoscopy, especially if there is no other obvious cause. During this test, a healthcare provider looks at the inside of your GI system with a camera attached to a long, flexible tube.
Colonic polyps, bleeding ulcers, and even gastrointestinal cancer can cause iron deficiency. Some other conditions include:
- Helicobacter pylori, a bacteria that can cause ulcers
- Celiac disease
- Autoimmune gastritis
Treating Iron Deficiency
Treatment of iron deficiency is based on two important approaches:
- Correcting the underlying problem
- Replacing iron levels
Replacing Iron Levels
Iron levels can be corrected by increasing iron in the diet or taking iron supplement pills. If your body can't absorb iron or you have an intestinal problem, however, taking a pill or eating food rich in iron won't correct the problem. In this case, you may receive an injectable form of iron.
Medical or Surgical Intervention
Some causes may require other types of intervention. For example, a bleeding polyp in your colon may need to be removed. A biopsy can test for cancer.
For some people, stomach bleeding may be related to the use of blood thinners. When this happens, you may need a lower dose or a different blood thinner. If you have had a major episode of blood loss due to something like surgery or trauma, you may need a blood transfusion.
Preventing Iron Deficiency
Healthy people can usually prevent iron deficiency with diet. Recommended intake differs for various people:
- Healthy adult males: 8 Milligrams (mg) per day
- Healthy premenopausal adult females: 18 mg per day
- Healthy pregnant females: 27 mg per day
- Healthy postmenopausal females: 8 mg per day
After menopause, healthy women need less iron because they do not experience blood loss due to menstruation.
Good dietary sources of iron include:
- Meat
- Poultry
- Legumes
- Oysters
- Tuna
- Pork
- Nuts
- Dark green vegetables
- Tomato juice
- Potatoes
You can help your body absorb non-heme iron by combining vegan sources of iron with a food rich in vitamin C. For example, drink a glass of orange juice with a plate of spinach, or add green peppers to beans.
You may need higher amounts if you have a condition that interferes with your iron levels. You may also need iron injections if you can't get enough through your diet or with an oral supplement.
Dietary Supplements
Most males and postmenopausal females get enough iron from food and should not take iron supplements unless prescribed by a doctor. Pregnant females should take prenatal vitamins, which usually contain iron. Women who have heavy periods may also need to take iron supplements.If you need to take an iron supplement, don'ttake more than 45 mg per day unless your doctor tells you to.
Even at recommended doses, iron supplements can cause constipation. They can also cause more serious side effects, such as iron toxicity. Iron supplements are especially dangerous for people who have hemochromatosis, a condition characterized by iron overload.
Adult iron supplements can be toxic for young children, so keep them in tightly capped, childproof bottles.
Summary
Iron deficiency is caused by not having enough iron in the blood. It can result due to one's diet, problems with iron absorption, or a health condition like Crohn's disease.
If iron deficiency leads to iron deficiency anemia, it can cause symptoms like weakness, dry skin and nails, and poor concentration. In severe cases, you may have heart palpitations and shortness of breath.
Iron deficiency can be diagnosed with blood tests, endoscopy, or a bone marrow biopsy. Treatment involves correcting the underlying cause and replacing lost iron. In otherwise healthy people, the condition can usually be prevented by making sure to get plenty of dietary iron.
