How to know if you are iron deficient
Beyond fatigue: from your hair to your brain, everything’s affected
Without sufficient iron, you are likely to feel very, very tired. But that’s just the start of it. And if you think you’re immune because you already eat plenty of iron-rich foods, think again. What you eat and what you absorb are two very different matters.
Iron deficiency is a leading risk factor for disability and death and is the most common nutritional deficiency across the globe, according to the World Health Organization. Are you one of the two billion people running on empty, without knowing it?
Shortness of breath and fatigue are the most obvious signs. That’s because without enough iron, your body can’t produce sufficient haemoglobin, a protein in red blood cells that enables the delivery of oxygen around the body.
There are other, lesser-known signs that you should be aware of. These include hair loss. If you are alarmed at how much you lose when you wash or brush your hair, or how dry it has become, don’t ignore the warnings. Be suspicious too if you have other visible symptoms, including spoon-shaped or brittle nails, sores at the corner of the mouth, and/or a sore tongue.
Other well-known symptoms include:
Headache
Restless legs syndrome
Ringing in the ears
Irregular heartbeat/palpitations
Less well-known is how iron deficiency can lead to poor brain function. Although adults can be affected, children are especially vulnerable to this, and the consequences can be dire. Childhood is a time of rapid growth and development, and the child’s brain will feel the brunt of any deficit.
During pregnancy, iron is critical for the developing foetus. Yet pregnancy is a time when iron deficiency is alarmingly common. It is associated with delayed cognitive development.
“It is unfortunately common to observe that severe iron deficiency during early childhood induces cognitive deficits that can persist after 10 years of treatment with iron.”
The problem can remain undetected for months, putting children at risk of developing psychiatric problems, including mood disorders, and the behavioural disorder ADHD.
If there is iron deficiency in early life, there is also greater risk of developing psychiatric problems as older children. Iron deficiency anaemia is: “probably related to childhood/adolescence-onset psychiatric disorders.”
Women and children first
Women are at particular risk because menstruation, pregnancy and childbirth all result in iron loss. In the UK, the latest diet and nutrition survey has indicated that an alarming 25% of women and 49% of girls aged 11–18 are iron deficient.
As well as women and children, groups most at risk include:
Anyone who’s undergone major surgery
Anyone with a gut disorder or peptic ulcer
Vegetarians and vegans
The last group is vulnerable because the most common cause of iron deficiency is dietary avoidance. Some people have little choice about what they eat, while others choose to avoid the richest, most bioavailable source of this mineral: red meat.
Studies of vegetarians around the world (Australia, Canada, China, England, Germany, Korea, New Zealand, South Africa, the United States) have found a high prevalence of iron deficiency among vegetarians, particularly women.
“The findings based on ferritin levels showed a high prevalence of iron depletion among vegetarian participants, especially among females.”
The irony (pardon pun) is that vegetarians probably eat just as much iron-rich food as meat eaters. The issue for them is that not much of that iron makes it to their blood. Iron status in vegetarians is often low, despite an iron intake that is comparable to that of omnivores.
There is, indeed, plenty of iron in plant foods, but it has very low bioavailability, meaning that instead of being absorbed, most of it sails straight through you on a sea of peristaltic waves. Your blood is not the final destination of this ship.
There are two forms of dietary iron: haem and non-haem. Haem iron has high bioavailability and is unique to animal-source foods, which also contain non-haem iron. Plant foods contain non-haem iron, but no haem iron.
The human gut can absorb 25% — 30% of haem iron from animal-source foods. That’s quite a good return: giving back is part of the circular nature of nourishment.
When it comes to non-haem iron from plant sources, you give nearly as much as you take. Non-haem iron absorption can be as low as 2%.
Because plant bioavailability of iron is so low, vegetarians should, according to one calculation, increase their dietary intake by 80%.
This lack of bioavailability from plant sources is a serious matter, because humans need a great deal of iron. It is the most abundant metal in the body, and the second most concentrated metal in the brain, after zinc. It is an essential component of myoglobin in muscle. Muscle contains approximately 60% of total body iron.
Blame it on the phytate
One reason for such poor bioavailability is the presence of phytates in plant foods. Phytate is “..of major concern for individuals who depend mainly on plant derivative foods”.
Phytate is a compound found in grains (especially those “healthy” wholegrains), seeds, nuts and beans. It forms complexes that bind not only to iron but also zinc and calcium. Because humans lack phytase, the enzyme that breaks down phytate, minerals pass largely unabsorbed through the body. And because phytate is heat stable, it is not easily degraded by cooking.
Although other processing methods such as soaking can reduce the phytate content to some extent, this effect is… “unlikely to be sufficient to overcome the shortfalls in iron, zinc, and calcium that have been consistently reported in cereal-and/or legume-based complementary foods.”
Like wholegrains, beans have high levels of phytate, but soya beans go the extra mile. Soya beans contain certain proteins that have an additional iron-blocking effect, independent of the phytate content. Therefore beans, especially soya beans, should not be considered a good source of iron.
“In areas of the world where cereal proteins are a major and predominant dietary factor, the associated phytate intake is a cause for concern”.
You can improve iron absorption from plant sources by consuming vitamin C-rich foods with your meal. Vitamin C is known to enhance uptake of non-haem iron, but it is considered unlikely to counteract the effect of iron inhibitors, such as phytate.
What to do?
If you suspect you may be iron deficient, your first port of call is your doctor. Don’t self-diagnose and then self-treat — get tested. Don’t take iron supplements if you don’t need them.
If your doctor carries out a blood test that reveals that you do indeed have low iron, he or she will decide you much you need to supplement, depending on the results. If your iron levels are exceptionally low, you may require intravenous iron.
You may find that your iron levels are normal, in which case explore other causes of your symptoms.
Low blood iron is generally easy to correct, even if your diet is devoid of this crucial micronutrient. But first, you need to know about it.