COLUMBUS, Ohio -- A new study at Ohio State University suggests that even mild iron deficiency may weaken bones and make them more likely to break.
The findings may soon call for a change in the diets of children, teenagers, and pregnant women -- all of whom have a high rate of iron deficiency in the United States.
Denis Medeiros, professor of human nutrition at Ohio State, led the study, which appeared in a recent issue of the Journal of Trace Elements in Experimental Medicine. Medeiros and his fellow researchers found that laboratory rats who were fed an iron-deficient diet showed evidence of weakened femur bones.
“This is despite the fact that the rats’ diets only resulted in minor iron deficiency, similar to that among humans,” said Medeiros. “And given the fact that iron deficiency anemia is so common, it’s remarkable that nobody examined the connection between iron and healthy bones before.”
The researchers fed some laboratory rats a healthy diet, while other rats ate a diet deficient in either iron or copper. X-rays of the rats’ legs revealed that the femurs of those with iron or copper deficiency each contained a pocket with lower bone density than normal. In tests, the femurs of the rats that were deficient in iron and copper were approximately 28 percent more likely to break than those of the rats on the healthy diet. The bones were tested after the rats were sacrificed.
According to Medeiros, the weakness in the bones of the iron-deficient rats is most important, since humans rarely have diets deficient in copper. Iron deficiency is quite common, but people are more likely to think they need calcium or vitamin C for healthy bones.
“We know that vitamin C deficiency leads to scurvy, and we know that calcium deficiency leads to osteoporosis, but if we just concentrate on those two, we might not be doing ourselves any favors. We’ve overlooked a very important nutrient,” said Medeiros.
Medeiros also said that since the study used young, growing rats, their closest human counterparts would be children and adolescents. Like children, pregnant women also need an iron-rich diet, and stand to lose the most through iron deficiency.
“The ones that are most at risk are newborns of mothers who haven’t eaten enough iron,” said Medeiros. “When babies are born, they should have enough iron stored up in their liver to last them for months, because milk is a very poor source of iron. But if the mother is iron deficient, the baby will be, too.”
Medeiros added that teenage girls are also much at risk, since they often put themselves on diets to lose weight, and end up skipping meals or not eating enough meat. Women in general are susceptible to iron deficiency, since they lose iron during their menstrual cycles.
The National Research Council has set the Recommended Dietary Allowance of iron for children 6 months to 10 years old at 10 mg per day, the same as for women after menopause and adult men. Adolescent boys should take in 12 mg per day. Adolescent girls and pre-menopausal women need 15 mg a day, while pregnant women need 30 mg.
Medeiros recommends that people who suspect they have an iron deficiency see a health care provider as soon as possible. Foods that are good sources of iron include red meat, liver, beans, and iron-fortified cereals and bread.
Iron supplements may be appropriate if they are recommended by a health care provider, but Medeiros warns that the bottles must be kept away from children. According to the Food and Drug Administration, since 1986, 110,000 children have become ill after overdosing on iron supplements.
Medeiros added another word of caution. “I don’t want to suggest that we’ve proven definitively whether iron deficiency leads to more bone fractures in humans. That will be our next step. We’ll look at this more in the future, and examine the effects of iron deficiency on other bones,” he said.
Medeiros said that he didn’t originally intend to study the effects of iron deficiency on the rats’ bones, but rather on their hearts, as part of a project funded by the United States Department of Agriculture and the National Institutes of Health. He and the other researchers examined the bones of the rats at the request of a former graduate student, Robert Wildman, now of the University of Delaware, who co-authored the study.
Other researchers included Laura Shiry, a graduate student in veterinary biosciences; Velimir Matkovic, a professor, and Jazminka Ilich, a research scientist, both of physical medicine and rehabilitation; and Bob Ireton, a student of osteopathic medicine at Ohio University.
Journal
The Journal of Trace Elements in Experimental Medicine