Have you been feeling tired lately? Can you barely make it up the stairs without getting winded even though you’re physically fit? If so, you may have an iron deficiency—especially if you’re a woman.
Although many people don’t think of iron as a nutrient, you may be surprised to learn that low iron is the most common nutritional deficiency in the United States. Nearly 10% of women are iron deficient, according to figures from the Centers for Disease Control. and Prevention.
Let’s look at why iron is so important to your body, what can happen if you don’t get enough of it, and when you need to take an iron supplement.
Why do you need iron?
Iron is an essential mineral. “The main reason we need it is that it helps transport oxygen around the body,” says Paul Thomas, EdD, RD, scientific advisor to the National Institutes of Health’s Office of Dietary Supplements.
Iron is an important component of hemoglobin, the substance in red blood cells that transports oxygen from the lungs to transport it around the body. Hemoglobin represents about two-thirds of the body’s iron. If you don’t have enough iron, your body can’t make enough healthy oxygen-carrying red blood cells. A lack of red blood cells is called iron deficiency anemia.
Without healthy red blood cells, the body cannot get enough oxygen. “If you’re not getting enough oxygen into your body, you’re going to get tired,” says Thomas. This fatigue can affect everything from brain function to the immune system’s ability to fight infection. If you are pregnant, severe iron deficiency can increase the risk of your baby being born prematurely or smaller than normal.
Iron also has other important functions. “Iron is also essential for maintaining healthy cells, skin, hair and nails,” says Elaine Chottiner, MD, clinical assistant professor and director of general hematology at the University of Michigan Medical Center in an email interview.
How much iron do you need?
How much iron you need each day depends on your age, gender and general health.
Babies and toddlers need more iron than adults, in general, because their bodies are growing so quickly. During childhood, boys and girls need the same amount of iron – 10 milligrams per day from ages 4 to 8 and 8 mg per day from ages 9 to 13.
From adolescence onwards, a woman’s daily iron requirement increases. Women need more iron because they lose blood every month during menstruation. Therefore, women between the ages of 19 and 50 need 18 mg of iron each day, while men of the same age can get by with just 8 mg.
After menopause, a woman’s iron needs decrease when the menstrual cycle ends. After a woman begins menopause, both men and women need the same amount of iron – 8 mg per day.
You may need more iron, either from food or from an iron supplement, if you:
- Are you pregnant or breastfeeding?
- Have kidney failure (especially if you are on dialysis, which can remove iron from the body)
- You have a wound, which can cause blood loss
- Have a gastrointestinal disease that prevents the body from absorbing iron normally (such as celiac disease, Crohn’s disease or ulcerative colitis)
- Take too many antacids, which can prevent the body from absorbing iron
- Have undergone weight loss surgery (bariatric).
- Exercise a lot (vigorous exercise can destroy red blood cells)
If you’re a vegetarian or vegan, you may also need to take iron supplements, because your body doesn’t absorb the type of iron found in plants as well as it does from meat.
How do you know if you have an iron deficiency?
“People often don’t know they have anemia until they have signs or symptoms — they look pale or ‘pale,’ are tired or have trouble exercising,” says Chottiner.
If you are iron deficient, you may also:
- Feeling short of breath
- Have a fast heart rate
- Have cold hands and feet
- Craving strange substances like dirt or clay
- Have brittle and spoon-shaped nails or hair loss
- Ulcers in the corners of the mouth
- Sore tongue
- Severe iron deficiency can cause difficulty swallowing
If you feel tired and fatigued, see your doctor. “It’s pretty easy to identify and diagnose the different levels of iron deficiency with a simple blood test,” says Thomas. Women who are pregnant and people with gastrointestinal disease such as Crohn’s, ulcerative colitis or celiac disease should have their iron levels tested regularly.
Do you need to take iron supplements?
If your iron is low, eating a diet high in iron-rich foods such as whole grains, red meat, dried fruit and beans may not be enough to give you what you need. Your doctor may recommend that you take an iron supplement.
Prenatal vitamins usually contain iron, but not all prenatal vitamins contain the recommended amount. Consult your doctor before taking any supplement.
While taking iron supplements, your doctor should test your blood to see if your iron levels have improved.
Can iron supplements cause side effects?
Iron supplements can cause side effects, usually stomach discomfort such as nausea, vomiting, diarrhea, dark stools, or constipation. Pregnant women are especially prone to constipation. Adding extra fiber to your diet can help relieve this symptom. Stool softeners can also make you feel better.
Starting with a low dose of iron and then gradually increasing the dose to the recommended daily dose can help minimize side effects. If the iron supplements are bothering your stomach, your doctor may adjust the dose or form of iron you use. You can also try taking the supplements with food.
Can you take too much iron?
Unlike some supplements, when it comes to iron, more is definitely not better. Adults should not take more than 45 mg of iron per day unless they are being treated with iron under close medical supervision.
For children, an overdose of iron can be especially toxic. “Iron supplements have killed young children because their need for iron compared to adults is relatively small,” says Thomas. If you take iron supplements, it is very important to store them in a high, locked cabinet, far out of the reach of children. Symptoms of iron poisoning include severe vomiting, diarrhea, abdominal pain, dehydration, and bloody stools in children.
It is difficult for adults to overdose on iron just from food and supplements, because the adult body has mechanisms to regulate the amount of iron it absorbs. However, people with the inherited condition hemochromatosis have problems regulating their iron absorption.
Although most people absorb only about 10% of the iron they consume, people with hemochromatosis absorb up to 30%. As a result, the iron in their bodies can build up to dangerous levels. That excess iron can deposit in organs such as the liver, heart and pancreas, which can lead to diseases such as cirrhosis, heart failure and diabetes. For that reason, people with hemochromatosis should not take iron supplements.