June 5, 2001 -- Adolescence can be one of the most trying times for girls — unwanted body hair, breasts, pimples, love woes.
A new study suggests iron deficiency is another common problem for girls between the ages of 12 and 16, and may be the reason many do poorly in math, compared to boys.
Previous studies have shown that girls have started to narrow the gap between boys when it comes to math scores, but on average they trail their male peers by 35 points on SAT scores.
The new study, in the June issue of Pediatrics links even mild iron deficiency with low math test scores.
Relationship Does Compute
Boys and girls with iron deficiency were twice as likely as those with normal iron loss to score below average on a standardized math test, the study found.
The study looked at 5,398 children who participated in a health survey from 1988 to 1994. Only 0.9 percent of the adolescent boys — ages 12 to 16 — reported iron deficiency compared to 8.7 percent of the girls.
"The relationship was there even with children without anemia," said lead author Jill Halterman, academic fellow at the University of Rochester in New York.
Severe iron loss, or anemia, is diagnosed with a simple blood test. But youngsters are not routinely screened for less severe iron deficiencies.
Average math scores for iron-deficient adolescents were about six points lower than those with normal iron levels. Among adolescent girls, the difference in scores was more than eight points.
Girls have a higher chance of iron loss due to blood loss through menses and rapid growth. Boys mostly experience iron loss during pubescent rapid growth but don't have the added iron loss from menses.
"When we screen for iron deficiency we screen for anemia so mild iron loss would not show up," Halterman said.
Call for More Studies
The findings appear to suggest that giving girls more iron may improve their math performance, but Halterman stressed the findings are preliminary.
"If the findings are confirmed by a prospective trial, then screening for iron deficiency might be warranted for high-risk children, which would be girls," Halterman said.
Halterman suggests parents make sure children, especially girls, get an iron-rich diet. Animal studies have shown that iron deficiency affects the brain's neurotransmitters. A comparable loss in humans may impact math comprehension.
Previous research has linked iron-deficiency anemia with lower developmental test scores in young children, but there is less information on older children and on iron deficiency without anemia.
"As more studies look at the question of math in particular, there will be a more solid foundation for asking about the mechanism," said Betsy Lozoff, director and senior research scientist at the Center for Human Growth and Development at the University of Michigan Medical School. "Medical practice doesn't change based on a single paper. There is need for replication."