Public Health

What doctors wish patients knew about iron deficiency

Sara Berg, MS , News Editor

AMA News Wire

What doctors wish patients knew about iron deficiency

Jan 25, 2024

Do you find yourself consistently fatigued despite getting sufficient sleep each night? If you're also dealing with symptoms like dizziness, lightheadedness or brittle nails, it is possible that you're lacking an essential nutrient: iron.

Iron is crucial for the formation of hemoglobin, which is a protein in red blood cells that carries oxygen from the lungs to the rest of the body. It is also involved in other important processes, such as energy production and the function of the immune system.

Half the dues, all the AMA benefits!

AMA membership offers unique access to savings and resources tailored to enrich the personal and professional lives of physicians, residents and medical students.

Yet while iron is naturally found in certain foods, many people fall short of meeting their recommended intake. This can lead to iron deficiency, which affects about 10 million people in the U.S. with 5 million having iron deficiency anemia.

The AMA’s What Doctors Wish Patients Knew™ series provides physicians with a platform to share what they want patients to understand about today’s health care headlines.

In this installment, two physicians took time to discuss what patients need to know about iron deficiency. These AMA members are:

  • Richard Eisenstaedt, MD, a former hematologist and current primary care internist in Abington, Pennsylvania, who serves as a delegate for the Pennsylvania Medical Society in the AMA House of Delegates.
  • Amar Kelkar, MD, MPH, a hematologist at the Dana-Farber Cancer Institute in Boston, Massachusetts, and delegate for the American Society of Hematology.

More than one-third of women under 50 are iron deficient. This can be attributed to menstruation, which is “the most common cause of iron deficiency” in women of child-bearing age, Dr. Kelkar said. “If you look at the amount of dietary iron that people need … menstruating women have the highest amounts of dietary iron needs to maintain adequate levels of iron in the blood and adequate hemoglobin.”

“There’s always been a fairly common prevalence of iron deficiency in women of reproductive years because of a tenuous balance between the amount of iron that we normally ingest and the amount that we absorb balanced by an obligate loss of iron,” Dr. Eisenstaedt said. “We ingest about 20 milligrams of iron a day and we absorb about 10% of that and we lose about one milligram of iron a day through normal gastrointestinal” (GI) epithelial cell shedding.

“Women who are menstruating lose another 30 milligrams a month or another milligram a day through menstrual blood loss,” he said. “If you add that up, you find that in women who are menstruating, the amount that you're losing—through no pathology, but just normal processes—is just about equal to the amount that you're absorbing.”

“In women who are menstruating, iron deficiency usually is a result of a subtle imbalance between what we’re eating and what we’re absorbing and what we’re excreting. It is very rarely a sign of more significant pathology,” Dr. Eisenstaedt said. Iron deficiency in women who are menstruating or are of child-bearing age “is not that big of a deal other than to recognize it and treat it.

“And it doesn’t necessarily suggest a problem with uterine pathology or GI [gastrointestinal] pathology. It’s just—fix the iron problem and you’ve pretty much solved the issue,” he added, noting that iron deficiency is “quite different in older people of either gender or in men.”

“If men are iron deficient, it’s almost always a sign of excess blood loss from the GI tract and it may be from a variety of pathological problems, including a cancer in the colon,” Dr. Eisenstaedt said. Such patients “could be slowly losing a little bit of blood each day without even noticing it.”

“Diagnosing iron deficiency anemia may be the clue to finding colon cancer at an earlier stage of its development, offering more potential for cure,” he said. “For older women and in all men, you need to think beyond menstrual blood loss and look for GI pathology. But in women who are menstruating, particularly younger women, that menstrual blood loss is likely the cause of the iron deficiency and doesn’t necessarily involve anything wrong with a reproductive tract.”

Related Coverage

6 things doctors wish patients knew about better nutrition

“Typically, when we see iron deficiency, we think of anemia, premature births or underweight births. Those are the kinds of manifestations that people should be thinking about,” Dr. Kelkar said. That’s because iron deficiency is underdiagnosed in pregnancy.

“During pregnancy, folic acid is another critical component of the red blood cell production system,” he said. “For anyone planning to become pregnant, they should start taking iron supplements before they even become pregnant because they’re going to be important early and during the whole development cycle of the pregnancy.”

“Iron deficiency has very nonspecific symptoms. The most common ones are going to be things like fatigue, generalized weakness, lightheadedness or dizziness,” Dr. Kelkar said. Other symptoms are “what we call pallor, which is pale skin or paleness of the sclera of the eyes, shortness of breath with activity or exercise intolerance if you’re very anemic.

“Sometimes it can look like headaches or even coldness of the hands or feet, or brittle nails,” he added.

Fortunately, “the tests to find iron deficiency are straightforward. You can get a ferritin level and the ferritin level is equal to the total iron your body stores,” Dr. Eisenstaedt said. “If the ferritin level is low, it’s iron deficiency. If the ferritin level is above a certain level, it’s clearly not iron deficiency. If it’s an in between level, it may or may not be, but most of the time it’s pretty straightforward.”

“Additional testing is based upon age, gender and any concomitant symptoms,” he said. For example, “a man who is iron deficient needs evaluation for their GI tract and, in general, they need a colonoscopy and often esophagogastroduodenoscopy, or EGD, as well.”

“Rarely, but in severe cases, they have unusual dietary cravings called pica that may include a craving for ice or a craving for starch or a craving for a strange food source,” Dr. Eisenstaedt. “But that tends to be more in the severe cases.”

“Traditionally, with pica you think about someone’s child eating dirt,” Dr. Kelkar said. “Basically, you’re having some urgency to replace an iron craving. But we don't have any way to manifest that.”

“So, oftentimes chewing ice is one of the most common and not-well talked about symptoms that I hear about from patients,” he said.

See what doctors want you to know

Get trusted insight from physicians on hot topics in today’s health care headlines—delivered to your inbox.

Illustration of two people talking

Patients should only take iron supplements “if they are iron deficient and their doctor recommends it,” Dr. Eisenstaedt said. “The reason for that is that a small proportion of the population has the exact opposite problem—they may have a genetic defect that leads them to absorb too much iron.

“And the consequences of absorbing too much iron may lead to liver and heart damage. So, you don’t want to do that and over correct what isn’t even a problem,” he added. “Certainly, it’s easy enough to screen women who are menstruating, especially if they have symptoms of fatigue or malaise or just not quite feeling themselves.”

“If you’re going to treat iron deficiency, it’s important to start slowly and to not give too much because patients develop vague abdominal symptoms, including cramps, abdominal pain, constipation, different color of their bowel movements,” said Dr. Eisenstaedt. When side effects do happen, “it is always important to tell your doctor when side effects are getting in the way of your taking the medicine.”

Additionally, it is important to “take an iron supplement with vitamin C—either a vitamin C supplement or with some actual citrus like orange juice—to help increase iron absorption,” Dr. Kelkar said.

“There are some patients who need parenteral iron treatment because they’re losing so much blood or not absorbing iron properly,” said Dr. Eisenstaedt. “We used to have just one parenteral iron preparation called iron dextran and that was associated with a lot of allergic and sometimes very serious anaphylactic reactions.”

“We now have a whole bunch of additional alternatives that are much safer to use so that parenteral iron is an easier option for patients who are intolerant of oral iron or not absorbing oral iron or are bleeding at a rate that exceeds their ability to replace their iron deficiency with oral medication,” he said.

“When you donate blood, they’re checking your blood count or hemoglobin level. They’re not checking the iron specifically,” Dr. Eisenstaedt said. “They’re seeing whether there are enough blood cells, which would be a manifestation of iron deficiency.

“And if you’re rejected for blood donation because of your anemia, you should definitely check that out with your doctor,” he added.

“Separate from supplements, you think about red meat, pork and poultry as types of foods that are enriched in iron,” Dr. Kelkar said, noting “seafood can carry a lot of iron and a lot of bean and legumes have iron.”

Additionally, “certain types of vegetables—specifically dark, leafy greens like spinach,” he said. “There are also some types of fruit that I tell patients about. Raisins and apricots are often rich in this. And then certain types of cereals, breads and pastas can have iron as well.”

“Part of the issue is that you can eat diets rich in iron and still not have enough iron … because there is some need for a balanced or mixed diet,” Dr. Kelkar said. “You need a certain amount of phytol and vitamin C in your diet to also help absorb iron.”

“Iron is pretty common in most nutritious diets … so it’s not typical that diet itself is the culprit when you’re seeing iron deficiency,” Dr. Eisenstaedt said. “It may be in people who are malnourished or who are poverty stricken who are in nutritional jeopardy for that reason. And in those situations, addressing a normal diet in a normal caloric nutritional need may be all that you need to do.”

“It’s best if you’re taking iron replacement to take them away from meals,” Dr. Eisenstaedt said, noting “there are a lot of fibers that can impair iron absorption. Grains and other cereals can also impair iron absorption.”

Additionally, “low acid levels in your stomach can impair iron absorption. So, it's best if you can avoid taking iron with an antacid or a proton pump inhibitor,” he said. “But in general, if you're using iron sulfate—the medicine—and you're taking it at 10 o'clock in the morning or 3 o'clock in the afternoon, not coincidental to ingesting a meal, you're going to have adequate amounts to heal the problem.”

“If you’re trying to increase absorption, taking an iron supplement with black tea—which has a lot of polyphenols—might reduce your absorption,” Dr. Kelkar said. “If you’re taking an iron supplement or eating iron rich foods and drinking milk at the same time, that might reduce absorption as well.

“And some of that’s related to the calcium in the milk that decreases absorption,” he added.

If iron deficiency goes untreated, “you can get very severely anemic to the point of having shortness of breath at rest or very little exercise tolerance,” Dr. Eisenstaedt said. “And if that severe anemia occurs in the face of concomitant heart disease or cerebral vascular disease, it may be a co-factor for a heart attack or a stroke.”

Ultimately, “your overall quality of life will be diminished, and it takes a long time to recover from that,” Dr. Kelkar said.