Iron is a mineral that plays a vital role in health and well-being. Without it, many bodily functions would malfunction.

“The primary role of iron is to carry oxygen in the blood to every cell in the body,” says Beth Thayer, RDN, MS, director of the Center for Health Promotion and Disease Prevention at Henry Ford Health System in Detroit.
Iron is an important component of hemoglobin, the protein in red blood cells that carries oxygen from the lungs and transports it throughout the body. If your body does not have enough iron, it cannot produce enough healthy oxygen-carrying red blood cells. Iron deficiency is one of the main causes of anemia, which means you have too little hemoglobin.
Women in their childbearing years are at higher risk for iron deficiency because of the loss of blood during menstruation. According to the Centers for Disease Control and Prevention, the recommended daily dietary allowance for iron for 19-to-50-year-old women is 18 milligrams (mg). Pregnant women should be consuming 27 mg per day. Adult men, on the other hand, need about 8 mg of iron per day.
“Women who are pregnant need the most amount of iron,” says Marilyn Murr, MD, clinical assistant professor of family and community medicine at the School of Medicine at the University of Texas Health Science Center at Houston. “The baby acts as a parasite taking iron, and the woman increases her blood volume to circulate through the baby and create the baby’s blood volume.”
There are two types of iron: heme iron from animal sources and non-heme iron from plant sources. Heme iron is absorbed more readily by the blood. Foods rich in iron include beef, liver, oysters, beans, fortified cereals, and dark leafy greens like spinach.
Insufficient iron levels can wreak havoc all over the body. Here are seven surprising signs of iron deficiency.

1. Extreme Fatigue and Exhaustion

The principle sign that your body is not getting enough iron may be the most difficult to link to iron deficiency.
“This is one of the most common signs of iron deficiency because it means your body is having trouble carrying the oxygen to your cells so it’s affecting your energy levels,” Thayer says.
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People lacking enough iron in their blood often feel sluggish, weak, and unable to focus. Though fatigue can be the sign of numerous conditions, if it does not go away with adequate rest, consider having your iron levels checked.

2. Frequent Infections

Iron plays a key role in a healthy immune system, so lower levels of the mineral can make someone more susceptible to infections. “Red blood cells help to transport oxygen to the spleen, which is one place where infections can be fought off,” Dr. Murr says.
Red blood cells also carry oxygen to the lymph nodes, which house infection-fighting white blood cells. “When someone has an iron deficiency, the white blood cells aren’t being produced as well, and they’re not as strong because they’re not getting enough oxygen, making that person more susceptible to infections,” she says.

3. Pale Skin

Though it’s not always the case, pale skin is often associated with being sick, and there’s good reason for that. Hemoglobin gives skin its rosy color, so low levels cause the skin to become lighter.
“When red blood cells become low with iron, they become smaller and paler in the center so skin also becomes paler,” Murr says. This may be easier to detect in people with lighter complexions, but no matter what your skin tone, if the area inside your bottom eyelid is lighter than normal, this may be a sign of iron deficiency.

4. Swollen Tongue

Lack of oxygen can also cause muscles to enlarge and become painful. “It happens to all the muscles really, but the tongue is the only one you can see,” Murr says. Cracks on the side of the mouth are also common among people with iron deficiency.

5. Restless Legs Syndrome

Some people who have iron deficiency develop restless legs syndrome, a disorder that causes you to have a strong urge to move your legs. The urge often comes with an unpleasant, crawling sensation in the legs that can make it hard to sleep.

6. Pica

People with iron deficiency may develop cravings for non-food substances, such as clay, dirt, or chalk, a condition known as pica.
Murr says scientists have yet to figure out why this happens to people when they do not get enough iron, but submitting to your cravings and eating these substances could be harmful. “Clay, chalk, and dirt would actually interfere with absorption of iron,” she says.

7. Hair Loss

Iron deficiency, especially when it develops into anemia, can cause hair loss. “When hair follicles don’t get enough oxygen, they go into a resting stage, and hair falls out and doesn’t grow back until anemia is improved,” Murr says. It is normal to lose about 100 strands of hair per day. However, if you notice your hair loss is excessive and it is not growing back, this may be a sign of iron deficiency.
If you’re experiencing these symptoms and think you may be iron deficient, speak to your doctor. He or she can help you find ways to include more iron-rich foods in your diet and determine whether you need to take iron supplements.