Women with even a small deficiency of iron may have a little more trouble thinking and remembering than those with adequate iron levels, U.S. researchers reported Monday.
They found that young women with mild deficiency but not medical anemia who took iron supplements for four months significantly improved their performance on tests of attention, short-term and long-term memory. They also did better on cognitive tasks.
In addition, anemic women clearly had trouble on the tests of mental performance, the team at Pennsylvania State University reported. The more anemic a woman was, the longer it took her to complete the tasks.
But when anemic women were given iron supplements, they also improved, the researchers told a meeting of the American Society of Nutritional Sciences, part of the Experimental Biology 2004 conference in Washington.
Dr. Laura Murray-Kolb and Dr. John Beard studied 113 women classified as either iron-sufficient, iron-deficient but not anemic, or anemic.
The women were then given either 60-milligram iron pills or placebos for 16 weeks.
They were examined at the beginning and end of the four-month period.
Before getting the pills, women who were iron-deficient but not anemic did as well on tests as women with normal iron levels, but it took them longer.
After taking the pills, they could work as fast, on average.
Leading nutritional disorder
Murray-Kolb said in the United States 9 percent to 11 percent of women of reproductive age are iron deficient and 25 percent of pregnant women are.
In the developing world 40 to 50 percent of women are anemic. The World Health Organization considers iron deficiency the leading nutritional disorder in the world, affecting 30 percent of the global population.
Iron deficiency causes poorer physical endurance, an impaired immune response, temperature regulation difficulties, changes in energy metabolism, and in children, a decrease in cognitive performance as well as negative affects on behavior.
But adult men and women past childbearing age are very unlikely to have iron deficiency and can develop iron overload, in which excess iron is found in the blood and stored in organs such as the liver and heart.
Some studies suggest but have not yet proven a link between high iron levels and heart disease.