An underdiagnosed deficiency of an essential mineral may be contributing to fatigue, brain fog and concentration problems in almost 1 in 4 adolescent girls and young women in the United States.
Almost 40% of American teenage girls and young women had low levels of iron, an important mineral needed to make red blood cells, a study published this week in JAMA found. It's the first research to look at iron deficiency in young women and adolescent girls.
For the study, researchers at the University of Michigan Medical School pulled data on girls and women ages 12-21 collected over the last 20 years from the National Health and Nutrition Examination Survey, part of the Centers for Disease Control and Prevention. They found 6% of the survey's sample had iron-deficiency anemia.
The findings weren't a surprise to pediatric hematologist-oncologist Dr. Angela Weyand, the lead author and an associate professor of pediatrics at the University of Michigan Medical School in Ann Arbor.
She often gets referrals from pediatricians and primary care physicians who suspect their patients might have an iron deficiency. She wondered how common the problem was.
“I hypothesized that I was just 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 reproductive age, but doctors don’t typically screen for iron deficiency. Weyand and her colleagues haven’t yet checked to see if iron deficiency is on the rise or has been consistently high for the last two decades.
What are symptoms of iron deficiency?
Often girls and young women don’t realize that what they’re feeling is a sign of an iron deficiency because the symptoms can be subtle or can be dismissed as being due to other problems like poor sleep, she said.
According to Weyand, symptoms of iron deficiency include:
- Fatigue.
- Cold extremities.
- Hair loss.
- Brittle nails.
- Cognitive issues like brain fog.
- Decreased athletic performance.
- Shortness of breath with exertion.
- Junk food cravings.
- Headache, lightheadedness.
- Sleep disorders.
Menstruation was a risk factor, although a quarter of the girls who hadn't started their periods yet had iron deficiency, the data showed.
Women and girls lose a lot of iron when they have heavy periods, but even when bleeding is in the normal range, iron stores can be depleted, Weyland said.
Those with low iron levels are often not discovered because doctors often test only for anemia, rather than the level of ferritin, a blood protein that contains iron and is a marker for stored iron, she 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’s Feinberg School of Medicine and an attending hematologist at the Ann & Robert Lurie Children’s Hospital of Chicago. She was not involved in the new research.
“The iron we take in every day goes into a checking account where it’s used to make new blood cells and other things that need iron,” she said. “If any is left over, it goes into the savings account. If you’re living from paycheck to paycheck with iron, you may not be able to keep up and have a surplus for when you’re having your period.”
Many of the symptoms 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’s not enough iron, fewer red blood cells are made, which is why you see symptoms like dizziness, headache, shortness of breath and fatigue.”
Those symptoms can be a big problem for teenagers, said Dr. Allison Wheeler, an associate professor in the department of pathology, microbiology and immunology at the Vanderbilt University Medical Center. Wheeler was not involved in the new research.
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“There are significant consequences especially in the adolescent age cohort where fatigue and poor concentration can lead to poor school performance,” she said. “And poor athletic performance can lead to changes in how girls think about exercise.”
Many women and girls with heavy periods — which experts blame for especially low ferritin levels — don’t know it’s not normal because of stigma and discomfort talking about their periods, Bercovitz said.
“People don’t tend to talk about how many times a day they’re changing pads or if they’re having leakage overnight,” she said. “They’re not talking with friends and sometimes not even with family members.”
What’s a normal period and what’s heavy?
It’s hard to draw an exact line. “But, if you’re changing your pad or tampon more often than every four to six hours, or if you have to sleep on a towel or use overnight pads plus period underwear because you leak, that’s heavy,” Bercovitz said.
There are a number of ways to keep your iron stores at a healthy level.
“You can add leafy green vegetables or meat to your diet,” she said. “Even cooking in a cast iron skillet can increase the iron in your food. If you’re still not getting enough iron in your diet, then iron supplementation would be a good idea.”
Other foods high in iron 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 rather than every day will lead to fewer side effects, such as abdominal pain or a bad taste in the mouth.
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“Some people have abdominal pain. The supplements can also cause constipation and occasionally diarrhea. Some people experience nausea, which is why it’s important to take them with food,” Bercovitz said.
She advises not taking the supplements with calcium-rich foods because calcium can block the absorption of iron.
“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 typically do not measure ferritin, women need to advocate for themselves, Wheeler said.
“There’s a lot of stigma around menstrual bleeding and it’s important that we talk about it in detail,” she added. “And it’s important that we as physicians listen to and trust our patients.”
