An underdiagnosed deficiency of an essential mineral may be contributing to fatigue, brain fog, and concentration problems in nearly 1 in 4 adolescent girls and young women in the United States.

Nearly 40% of American teen girls and young women had low levels of iron, an important mineral needed to make red blood cells, according to a study Posted this week in JAMA Found. It is the first investigation that analyzes iron deficiency in young women and adolescents.

For the study, researchers at the University of Michigan Medical School drew data on girls and women ages 12 to 21 collected over the last 20 years of the National Health Survey and Nutrition Examination, part of the Centers for Disease Control and Prevention. They found that 6% of the survey sample had iron deficiency anemia.

The findings were not a surprise to pediatric hematologist-oncologist Dr. Angela Weyand, lead author and associate professor of pediatrics at the University of Michigan Medical School in Ann Arbor.

He often receives referrals from pediatricians and primary care physicians who suspect their patients may be iron deficient. He wondered how common the problem was.

“I assumed that I was only seeing the tip of the iceberg, and unfortunately that is true,” Weyand said.

The CDC recommends a blood test for anemia every five to 10 years for women of childbearing age, but doctors often don’t detect iron deficiency. Weyand and her colleagues have not yet verified whether iron deficiency is on the rise or has been consistently high over the past two decades.

What are the symptoms of iron deficiency?

Girls and young women often don’t realize that what they’re feeling is a sign of iron deficiency because the symptoms can be subtle or can be dismissed as due to other problems, such as lack of sleep, she said.

According to Weyand, symptoms of iron deficiency include:

  • Fatigue.
  • Cold extremities.
  • Hair loss.
  • Brittle nails.
  • Cognitive problems such as brain fog.
  • Decreased athletic performance.
  • Difficulty breathing with exertion.
  • Junk food cravings.
  • Headache, lightheadedness.
  • Sleep disorders.

Menstruation was a risk factor, although a quarter of girls who had not yet started their periods were iron deficient, the data showed.

Women and girls lose a lot of iron when they have heavy periods, but even when bleeding is within the normal range, iron stores can be depleted, Weyland said.

Those with low iron levels often go undetected because doctors often only test for anemia, rather than the level of ferritin, a protein in the blood that contains iron and is a marker of stored iron, he said.

Think of ferritin as an indicator of how much is in your «iron savings account,» said Dr. Rachel Bercovitz, an associate professor of pediatrics at Northwestern University Feinberg School of Medicine and an assistant hematologist at Ann & Robert Lurie of Chicago. . She was not involved in the new research.

“The iron we eat every day goes into a checking account where it is used to make new blood cells and other things that need iron,” he said. “If there is anything left over, it goes into the savings account. If you live paycheck to paycheck with iron, you may not be able to keep up and have a surplus by the time you get your period.”

Many of the symptoms that girls experience are related to the impact of iron deficiency on hemoglobin, a protein in the blood.

«Iron is the key ingredient in hemoglobin, and essentially red blood cells are bags of hemoglobin that carry oxygen to tissues,» Bercovitz said. «When there is not enough iron, fewer red blood cells are produced, so symptoms such as dizziness, headache, shortness of breath and fatigue occur.»

Those symptoms can be a big problem for teens, said Dr. Allison Wheeler, an associate professor in the department of pathology, microbiology and immunology at Vanderbilt University Medical Center. Wheeler was not involved in the new investigation.

«There are significant consequences, especially in the adolescent age cohort, where fatigue and lack of concentration can lead to poor school performance,» he said. «And poor athletic performance can lead to changes in the way girls think about exercise.»

Many women and girls with heavy periods, who experts blame for especially low ferritin levels, don’t know it’s not normal because of the stigma and discomfort of talking about their periods, Bercovitz said.

“People don’t tend to talk about how many times a day pads are changed or if they leak overnight,” he said. «They’re not talking to friends and sometimes not even family members.»

What is a normal period and what is heavy?

It is difficult to draw an exact line. “But if you change your pad or tampon more often than every four to six hours, or if you have to sleep on a pad or wear pads and underwear for your period because it leaks, that’s heavy,” Bercovitz said. .

There are several ways to keep your iron stores at a healthy level.

“You can add green leafy vegetables or meat to your diet,” he said. “Even cooking in a cast iron skillet can increase the iron in the food. If you still don’t get enough iron in your diet, then it would be a good idea to take iron supplements.»

Other iron-rich foods include:

  • Eggs.
  • Seafood, such as tuna or sardines.
  • Tofu.
  • Beans.

Studies have shown that an iron supplement every other day works for people with mild iron deficiency and anemia. Taking them three days a week instead of every day will cause fewer side effects, such as abdominal pain or a bad taste in your mouth.

“Some people have abdominal pain. The supplements can also cause constipation and sometimes diarrhea. Some people experience nausea, so it’s important to take it with food,» Bercovitz said.

She advises against taking the supplements with calcium-rich foods because calcium can block iron absorption.

“You can increase the amount of iron absorbed by taking supplements with a cup of orange juice,” Bercovitz added.

Another approach is to use birth control pills or other methods that can reduce bleeding during menstruation.

Because doctors don’t usually measure ferritin, women must advocate for themselves, Wheeler said.

“There is a lot of stigma around menstrual bleeding and it is important that we talk about it in detail,” she added. «And it’s important that we as physicians listen to and trust our patients.»