The link between low iron levels and fatigue, and why this diagnosis is often missed

Share This Post

Today’s edition of the British Medical Journal contains an article which summarises guidance from the UK’s National Institute of Health and Clinical Excellence (NICE) on the management of chronic fatigue syndrome [1]. Let me start by saying I have special interest in this area, as quite a number of my patients present with ‘fatigue’ (often, long-lasting) for which no specific cause can be found.

My experience is that it is often able for individuals to regain much if not all of their lost energy using, usually, a range of approaches which may address more than one apparent cause. While the recommendations from NICE are better than nothing, my sense is that we prove to be of much use for a significant number of sufferers.

One of the reasons for this is that the recommendations do not embrace some issues that I find are common in CFS including compromised adrenal gland function. And even where a testing is advised, there are reasons why conventional interpretation of results may ‘miss’ something that is relevant clinically.

By way of example, I’m going to focus on NICE’s recommendation to measure ‘ferritin’ levels. Ferritin actually gives a pretty good measure of iron levels in the body. Low iron can cause anaemia (which can cause fatigue), but even if it doesn’t, on it’s own deficiency of this nutrient can cause fatigue. What is more, low iron (ferritin) is common in CFS sufferers, and restoring iron levels often leads to a significant improvement in energy and wellbeing.

NICE’s recommendations are that ferritin levels should be taken in children and young people only. Personally, I don’t agree with this, because in practice I see iron deficiency very commonly in vegetarians (of all ages) and women.

Next, I do think with iron levels it’s important to distinguish what is ‘normal’ from what is ‘optimal’. This week, I’ve been doing some work in Canada which has entailed, among other things, advising people on the results of their ‘medicals’. Ferritin levels are measured in women as a matter of course over here, and the normal range is quoted as 10 – 291 micrograms per litre of blood (mcg/L). Just seeing how wide this ‘normal’ range is set should set alarm bells a’ringing. Are we really saying that two individuals, one with 29 times the iron level of the other, are both ‘normal’.

You see, what is ‘normal’ is something determined by statistical techniques, not common sense, and is utterly arbitrary. Basically, the normal range for ferritin is set too wide. We know this partly from our experience in clinical practice, and partly because there is even some evidence that shows that individuals with iron levels well within the ‘normal’ range can still suffer as a result.

I suppose one of the reasons that I’m writing about this is that almost all the women I have seen this week has ferritin levels that I regard as far from optimal. And none of them had had this mentioned to them or had any advice given regarding this. The most memorable of these was a women who complained she lacked ‘stamina’. She turned in a ferritin of 4 (yes, four). And despite this being even lower than the ‘normal’ range, this seemed to have been ignored by her doctor. Personally, I think iron does not get enough attention, and yet I find it’s often critically important to those who are suffering from chronic fatigue or simply feel ‘below’ par.

The article pasted In below includes more information of the value of optimal iron levels with regard to brain function, and also offers some advice about iron supplementation.


1. Baker R, et al. Diagnosis and management of chronic fatigue syndrome or myalgic encephalomyelitis (or encephalopathy): summary of NICE guidance. BMJ 2007;335:446-448

Metal fatigue – iron deficiency found to slow brain function in women – posted on 12 March 2007

While medical practice generally turns a blind eye to the value of nutrition in health, it has at least embraced the importance of certain specific nutrients including iron. Iron is important for the manufacture of haemoglobin ” the protein in the red blood cells responsible for carrying oxygen around the body and delivering it to the tissues. Iron deficiency can lead to anaemia, which can lead to symptoms which include fatigue and low mood.

What is less well recognised about iron is that it participates in the reactions that generate energy within the body. It is possible for individuals to become iron deficient without becoming anaemic. However, iron deficiency in the absence of anaemia can still cause individuals to suffer symptoms such as fatigue and low mood. This is particularly common in women of child-bearing age, particularly as a result of loss of iron via menstrual blood each month.

The relationship between iron status, anaemia and mental function was recently studied in a group of 149 women aged 18-35 years. At the beginning of the study, women were classified as being either iron-sufficient, iron deficient and anaemic, or iron deficient in the absence of anaemia. All women were put through their paces with 8 tests of mental function.

At the beginning of the study, the iron-sufficient women performed better and completed the mental tasks more quickly than the iron deficient anaemic women. Cognitive performance and task completion results among the iron deficient non-anaemic women fell between the iron sufficient women and iron deficient anaemic women.

Women who were iron deficient were then treated with iron supplements for a period of 8 weeks. At the end of the study, a significant improvement in serum ferritin was associated with a 5-7 fold improvement in mental function. The authors of this study concluded, Iron status is a significant factor in cognitive performance in women of reproductive age. They went on to add that the severity of iron deficiency affects accuracy of cognitive function over a broad range of tasks.

In medicine, we commonly check for anaemia. However, we much less commonly check for iron status. I do think it is important for individuals to be alert to the fact that iron deficiency in the absence of anaemia have adverse effects on health and wellbeing.

In my experience, the best test for iron levels in the body is what is known as the ‘serum ferritin’. It is my experience is that ferritin levels of less than about 50 are generally associated with symptoms such as fatigue, low mental energy and low mood. As I said, women of child-rearing age are at risk of this. This is particularly true for vegetarians and vegans in my experience.

Those not wishing to stoke up on liver and red meat may wish to contemplate supplementation. Many iron supplements are not well absorbed, however. One that I find useful in practice is Floradix – a liquid form of iron that is available from most health food stores.


1. Murray-Kolb LE, et al. Iron treatment normalizes cognitive functioning in young women Am J Clin Nutr, 2007;85(3): 778-787

Dr Briffa’s new book ” Waist Disposal ” the Ultimate Fat Loss Manual for Men ” is now available. To learn more about the book click here.

To buy Waist Disposal from click here.

More To Explore

Walking versus running

I recently read an interesting editorial in the Journal of American College of Cardiology about the relative benefits of walking and running [1]. The editorial

We uses cookies to improve your experience.