Iron supplementation decreases fatigue by almost 50% in nonanemic women

Iron supplementation reduced fatigue by almost 50% in women who are low in iron but not anemic, according to the results of a clinical trial published July 9 in CMAJ (Canadian Medical Association Journal).

"We found that iron supplementation for 12 weeks decreased fatigue by almost 50% from baseline, a significant difference of 19% compared with placebo, in menstruating iron-deficient nonanemic women with unexplained fatigue and ferritin levels below 50 μg/L," writes Dr. Bernard Favrat, Department of Ambulatory Care and Community Medicine, University of Lausanne, Switzerland, with coauthors.

The study, a randomized controlled trial involving 198 menstruating women between the ages of 18 and 50 years, included daily oral supplements of 80 mg of prolonged-release ferrous sulfate as well as placebo. The trial was double-blinded, meaning neither the participants nor the health care providers knew which group was receiving the supplement versus placebo.

Fatigue is common in patients in primary care practices, with 14% to 27% suffering from fatigue and 1% to 2% of visits specifically for fatigue. Women are three times more likely than men to report fatigue. Positive effects on hemoglobin, ferritin and other blood levels were evident as early as six weeks after iron supplementation.

The authors note that iron did not affect anxiety or depression scores or quality-of-life indicators such as physical and psychological performance.

"Iron deficiency may be an under-recognized cause of fatigue in women of child-bearing age," write the authors. "If fatigue is not due to secondary causes, the identification of iron deficiency as a potential cause may prevent inappropriate attribution of symptoms to putative emotional causes or life stressors, thereby reducing the unnecessary use of health care resources, including inappropriate pharmacologic treatments," conclude the authors.