Nearly 40 percent of girls and young women in the US have insufficient levels of iron in their blood, which can lead to symptoms such as fatigue, brain fog, and hair loss. Of these, 16 percent also have iron deficiency anemia, a potentially serious condition in which a lack of iron leads to a reduction in red blood cells, which carry oxygen throughout the body.
Researchers have previously measured rates of iron deficiency and anemia in high-risk populations, such as those with heavy menstrual bleeding. Studies investigating their prevalence in the US have also explored these conditions in a regional level.
To better understand its prevalence on a national scale, Angela Weyand at the University of Michigan and colleagues analyzed blood samples and demographic data from 3,490 girls and women, ages 12 to 21, who participated in surveys across the US between 2003 and 2020. Transgender people were not included in the study .
They found that 39 percent of the participants were iron deficient, which they defined as having levels of ferritin, an iron-binding protein, of less than 25 micrograms per liter. Of these, 16 percent had anemia, defined as hemoglobin levels below 120,000 micrograms per liter.
This is probably largely because of their diets, Weyand says. “There have been nutrition studies that show that overall in the United States, the iron content of the foods we eat has decreased over time,” she says. “People are eating less red meat and more are going vegan or vegetarian.”
Supplements can boost a person’s iron levels, but insufficient evaluation means many don’t know they need them, Weyand says. In the United States, the Centers for Disease Control and Prevention recommends that girls and women starting at age 12 be screened every five to 10 years for anemiabut most are not, Weyand says.
People with heavy periods may not seek medical attention for their symptoms, and many doctors may not ask about them, she says.
If not treated, anemia has been linked to an increased risk of infections, as well as complications related to the heart and lungs. Iron deficiency can also cause complications before and after delivery, Weyand says, even though none of the study participants were pregnant.
Female iron deficiency and anemia extend well beyond the US, particularly in low-income countries where malnutrition can be high and access to health care is often poor, she says Sant Rayn Pasricha at the University of Melbourne in Australia. Therefore, these areas should be a particularly high priority for detection and treatment, says Pasricha. Poverty increases the risk of iron deficiency, in part because red meat and other iron-rich foods can be expensive, Weyand says.
But Laura Murray-Kolb at Purdue University, Indiana, says the cutoff the researchers used to define iron deficiency is higher than 15 micrograms per liter or below the most commonly used figure. The higher the cutoff, the more prevalent the condition will appear, she says.
