Iron is a mineral that’s found naturally in many foods, but a surprisingly large number of people don’t get enough of it. And iron deficiency can cause a range of health issues—and even directly impact your brain health.

That’s the takeaway from recent research that found low iron levels can exacerbate symptoms of anxiety, depression, and schizophrenia. The meta-analysis analyzed survey results and studies, and found that a number of people with depression, anxiety disorders, sleep disorders, and psychotic disorders also reported having a history of iron deficiency anemia.

Iron deficiency is a common problem. Research shows that up to 10.5 percent of Americans have iron deficiency anemia, which is a condition where your body doesn’t have enough healthy red blood cells. But iron deficiency does more than impact your mental health—it can impact your heart and even cause issues in pregnancy.

With that in mind, what are the signs of iron deficiency and what should you do if you suspect your levels are low? Dietitians break it down.

Signs of iron deficiency

It’s important to know this upfront: It’s not always easy to tell if you have low iron levels. “Signs and symptoms of iron deficiency anemia are unreliable in screening for or detecting this type of nutritional anemia,” says Deborah Cohen, DCN, RDN, associate professor in the department of clinical and preventive nutrition science at Rutgers University. The symptoms also tend to be a little nondescript and can easily be confused with those of other conditions, says Jessica Cording, RD, author of The Little Book of Game-Changers.

Still, there are a few signals that you may be dealing with an iron deficiency. Keep these in mind.

1. You feel tired and weak

Fatigue is one of the most common symptoms of iron deficiency. With iron deficiency anemia, your body can’t make enough hemoglobin, a substance in red blood cells that allows them to carry oxygen, explains Sonya Angelone, RDN, a spokeswoman for the Academy of Nutrition and Dietetics. “Less oxygen getting to tissues leads to fatigue,” she says. There is a range, though, depending on how severe your iron deficiency is. “You may feel a little tired or really tired,” Cording says.

2. Your skin is paler than usual

The reason for this is simple, Angelone says: Hemoglobin gives red blood cells their red color, so lower levels of hemoglobin with iron deficiency make skin look less red. However, given that a lot of factors can impact your skin color, this can be a tricky symptom to pin to iron deficiency, Cording says.

3. You have shortness of breath

Again, there are several things that can cause shortness of breath. But having low oxygen levels from iron deficiency is one of them, Angelone says. “This leads to a faster breathing rate since the body is trying to get more oxygen,” she says. “You will notice shallow, more rapid breathing.”

4. You’ve been dealing with headaches and dizziness

Iron deficiency anemia can cause your brain, along with other organs, to receive less oxygen than it needs to work at its peak performance—and that can lead to headaches, Cording says. Research has found that up to 80 percent of people with anemia experience headaches and 36 percent have migraines.

5. You have cold hands and feet

An iron deficiency causes less oxygenated blood to get to your hands and feet—and that can leave them feeling cold, Angelone says. While some people are just more prone to having cold hands and feet, if this is a newer thing for you and you experience it with other symptoms of anemia, Cording says it’s worth pursuing.

6. You have “spoon” nails

Spoon nails (aka koilonychia) are soft nails that have raised edges and a depression in the center, and the center is usually large enough to hold a drop of liquid, the Mayo Clinic says. Spoon nails can be a sign of several conditions, including heart disease and hypothyroidism, so it’s worth mentioning to your healthcare provider.

7. You’re irritable

Having an iron deficiency can just make you feel… off, Cording says. You may be more tired than usual, you could be dealing with headaches, and you just may not feel like yourself. With that, you may be more likely to get annoyed easily. But, again, this can be a tough symptom to pin down. “Because the signs and symptoms are so vague and could be attributed to so many conditions, iron deficiency is often not diagnosed in its early stages,” Cohen says.

What to do if you have low iron levels

If you suspect that you have low iron levels, it’s important to talk to your doctor. “If you have any of these symptoms, it’s always a good idea to get checked,” Cording says. “Nutritional deficiencies are important to look at.”

Your doctor can order a basic lab test to check your red blood cells and hemoglobin levels—these will be low if you have an iron deficiency, Cohen says.

If you are, in fact, low in iron, there are a few steps you can take to fix it. “If it’s a very mild deficiency, sometimes being more mindful of food sources can help,” Cording says. That can mean eating more beef and chicken or, if you’re a vegetarian, focusing on having things like tofu, spinach, and kidney beans.

If your deficiency is more severe, your doctor may recommend you take a supplement, Cohen says. It’s just not a good idea to diagnose yourself with iron deficiency and put yourself on iron supplements without talking to your doctor first. “Supplements have side effects—constipation being the most common, [along with] nausea and gastrointestinal upset,” Cohen says. “The symptoms also might be due to another cause and thus, the supplement will just be a ‘Band-aid’ and cover up the symptoms of a more serious condition.”

Cording stresses the importance of getting checked out if you suspect you have an iron deficiency. “Any time you’re not feeling like yourself, it’s important to talk to your doctor,” she says.