Iron may help fatigue in women even when haemoglobin OK
30 May 2003
Iron supplementation may benefit fatigued women of childbearing age even if their haemoglobin level is within the normal range, a primary care study shows.
However, the study indicated that the effect may be confined to those women with serum ferritin concentrations at 50 microgram/L or lower.
(Ferritin is a protein that stores iron in the body. The serum ferritin level is tested to indicate the total amount of iron in the body. The normal level for women less than 50 years of age is 15-200 microgram/L. Haemoglobin is an iron-containing protein that transports oxygen in the blood. A low level of haemoglobin in the blood can indicate anaemia.)
The randomised controlled trial found that non-anaemic women presenting with unexplained fatigue improved after a month on iron supplements compared to a matched group given placebo (a dummy medication).
The study, completed by 136 women aged 18 to 55 years, was conducted in an academic primary care centre and 8 general practices in Switzerland.
The level of fatigue after 4 weeks decreased by 29 per cent in the group given 80 mg/day of oral long acting ferrous sulphate (an iron supplement) and decreased by 13 per cent in the placebo group (British Medical Journal 2003; 326: 1124).
The authors said they found a significant response only in the patients with low or borderline serum ferritin concentrations.
'This suggests that iron deficiency could be present even with a 'normal' concentration of serum ferritin,' the researchers said.
They said the study had several limitations including that the primary outcome focused on fatigue, which was a patient-centred subjective measure.
However, identifying iron deficiency without anaemia as a potential cause of fatigue was important and may avoid the inappropriate attribution of symptoms to emotional causes or life stressors, they concluded.
Women with haemoglobin concentrations less than 117 g/L, other obvious physical or psychiatric cause of fatigue, and women with chronic fatigue syndrome were excluded from the study. (Normal haemoglobin level for women is 119-160 g/L.)
Last Reviewed: 02 June 2003
- 1. Medical Observer Weekly 30/5/03
