Eat to Thrive Podcast #7: Are you getting enough iron?
In time for World Iron Awareness Week (26 August - 1 September), I take a look at how you can do your best to avoid the most common and widespread nutrient deficiency in the world.
I guess a good place to start is - what is iron, and why do I need it?
Iron is one of the essential micronutrients we require in our diet. We need to get quite a few vitamins and minerals from our food, and iron is one of the minerals. It’s also an element, so it appears on the periodic table of elements (its symbol is Fe and atomic number is 26).
It’s a trace element, or trace mineral, which means we require less of it each day than the seven major minerals, and it occurs in smaller amounts in our bodies, at less than 5 grams.
An average adult human body contains around 4 grams of iron - around 60% of this is incorporated into a special molecule called haemoglobin and about 25% is stored in the liver. The rest is distributed in muscles, enzymes and transport molecules.
Now haemoglobin is pretty amazing. It’s a special molecule made of protein and four iron atoms. Each haemoglobin molecule can bind to four oxygen molecules – one for each iron atom. But wait, this is where the numbers get scary big. Every red blood cell in your body contains around 300 million haemoglobin molecules, so every red blood cell can transport 1.2 billion oxygen molecules. Now think of how many red blood cells are in your body…whoah.
Considering the fact that iron is an essential part of the structure of haemoglobin, and haemoglobin carries oxygen from our lungs to all the tissues in our body to be used for cellular respiration, you can see that being short on iron can have a pretty significant impact on how you feel. Without a good supply of oxygen, our bodies find it hard to access the energy in our food, leaving us feeling really tired. Iron is also important for brain development and growth (babies iron needs really jump at 6 months of age, as they are born with enough iron stores for only the first 6 months of their lives), for cognitive performance, and for and for the proper functioning of our immune system.
How common is iron deficiency?
According to the World Health Organization, iron deficiency is the most common and widespread nutritional deficiency in the world. It is most prevalent in non-industrialised countries, but it’s still estimated that between 30-40% of pre-school aged children and pregnant women are iron deficient in industrialised countries. When you know how important iron is for cognitive development, you start to appreciate the gravity of the situation, and the potential for life-long effects for those pre-schoolers, and for the babies those pregnant women are carrying.
Latest figures in New Zealand show that 1 in 14 women are iron deficient, and over a third of teenaged girls don’t meet their daily iron requirements. Even more concerning is that 8 out of 10 toddlers aren’t meeting their dietary iron needs, and 14% of children under the age of two are iron deficient.
So, who is most at risk of an iron deficiency?
Infants 6 months of age onwards: due to reaching the end of the iron stores they have when they are born. Babies born to iron-deficient mothers will have smaller iron stores, and may need more iron that what is supplied in breast milk, as it’s not a very good source.
Toddlers, children and teenagers: due to their rapid growth and development, and therefore their significantly increased iron requirements.
Teenaged girls and women: due to the losses from having periods.
Pregnant women: due to the iron requirements of the growing baby.
Breastfeeding mums: due to the loss of iron in breast milk, although not having a period during this time can compensate for this quite well.
Vegetarians or vegans: on a poorly planned diet, also people on restrictive or fad diets that are low in energy or eliminate whole food groups.
Athletes and the very physically active: due to increased requirements
The elderly can also be at risk: due to factors including loss of appetite, difficulty chewing or swallowing, and economic concerns.
How do I know if I'm iron deficient?
Iron deficiency progresses through a few stages – the longer you don’t meet your iron requirements, the more deficient you become, the crappier you feel.
The first stage is the depletion of the body’s iron stores. The body is incredibly resourceful, and if you’re just not getting the iron you need in your diet, it’ll dig into its reserves, I guess if the pantry is empty it’ll rummage through the freezer for the goodies. You’ll likely not feel any symptoms at this stage, because your body is making use of what it put aside for a rainy day, but when the stores run out, there will be a decrease in a marker in your blood called serum ferritin, that can be measured in a blood test.
The second stage is when the lack of iron starts leads to a reduction in the number of red blood cells produced, and the iron levels in the blood decrease, measured by a blood test of serum iron.
The third stage is really serious, and you’ll have low haemoglobin levels, low iron levels, and small, pale red blood cells. You will now be suffering from iron-deficiency anaemia. You’ll be feeling weak and fatigued, have pale skin, feel really cold, and your brain just won’t be working at full capacity. You might also experience a bit of restless leg syndrome, or develop spoon-shaped nails.
The important thing to know is that feeling really tired is a symptom common to many health issues. Just because you are tired all the time, doesn’t mean you have iron deficiency anaemia, and you certainly shouldn’t head to the local pharmacy and start necking iron pills. You need to get yourself checked out by your GP, who will likely order some blood tests to check your iron levels, but importantly also look at other potential causes of your fatigue just in case there’s something else going on.
One danger of just going straight for the iron pills is that there is a condition called haemochromatosis, or iron overload, which has the complete opposite effect on your iron levels, but one of the major symptoms is fatigue! Haemochromatosis is actually pretty common, around 1 in 200 New Zealanders have the condition, and the high iron levels can cause organ damage if not detected and treated.
The big takeaway point here would be if you are continually tired, cold, look pale, and you’ve got some serious brain fog going on, don’t be tempted to self-diagnose; get it checked out by your GP.
OK, so I've been told I have iron-deficiency anaemia by my doctor - what next?
It’s fairly likely you will have been prescribed iron tablets, to boost your iron levels in a short space of time. If things are really low, you may even have been given an injection at the doctors. While the tablets are a good short-term strategy to get you back on track, you’ll need to take a look at your diet and make a few changes that will help boost the iron you get from food. Also, the tablets can have some fairly unpleasant side-effects, like constipation, indigestion and nausea, and they tend to turn your poo a really dark and scary colour…! Some iron tablets come with vitamin C in them, which helps with iron absorption. If the ones you have been prescribed don’t have the vitamin C added, eat a piece of fruit at the same time you take your tablet – an orange, a mandarin or a kiwifruit are great options – and this will help you absorb the iron from the tablets.
On the other hand, if you have been told your iron stores are depleted, but you don’t yet have anaemia, you may have been given some dietary advice instead.
So, what can I do to increase the amount of iron in my diet, and what are some ways to maximise the amount my body absorbs?
There are two types of iron in food: haem iron and non-haem iron.
As the name suggests, haem iron is the type found in haemoglobin, the same stuff as in our blood. Haem iron is found in meat, liver, chicken, pork, fish and seafood, and is easily absorbed by the body.
Non-haem iron is found in plant foods, like beans, lentils, chickpeas, cereals, grains, tofu and some vegetables like spinach and broccoli. It isn’t quite as easily absorbed by the body, and there are a few things that hinder its absorption as well as a few things that help.
If you regularly eat a variety of animal food and have a balanced diet, it’s unlikely you will become deficient in iron in the absence of any underlying health issues. However, if you’re not regularly eating a variety of foods from the four food groups, or you are vegetarian or vegan, it might take a bit more planning to avoid becoming iron deficient.
Top tips for improving your iron levels:
If you eat meat and seafood, try and eat a variety: lean red meat is the best source of haem iron, and chicken, poultry, pork, fish and other seafood contain useful amounts too.
If you follow a plant-based diet but still eat meat and seafood from time to time, then combining those animal foods with plant foods rich in non-haem iron at the same meal will enhance the absorption of the non-haem iron.
If you don’t eat animals, then you’re going to have to eat smarter! Non-haem iron takes a bit more encouragement on the absorption front, but there a few tricks you can use:
Include as many non-haem iron foods in your diet as you can – variety is key. Tofu, beans, lentils, spinach, broccoli, wholegrain cereals and breads, tomatoes, nuts and seeds (especially sunflower seeds), dates, figs, and eggs if you eat them.
Choose iron-fortified breakfast cereals and other iron-fortified foods when you can. Some milk alternatives are fortified too, if you don’t drink cow’s milk.
Eat foods rich in vitamin C at the same time as foods containing non-haem iron. Citrus fruits, kiwifruit and red capsicum are great sources of vitamin C.
Avoid drinking tea with your meals, or within an hour of eating. Tea contains tannins which reduce the amount of iron you absorb.
If you are taking calcium supplements, avoid taking them with your meals.
Take look at this excellent downloadable handout from Health Info Canterbury to see what sort of foods to choose for an iron-rich diet.
Health Navigator. (2019). Anaemia. Retrieved from https://www.healthnavigator.org.nz/health-a-z/a/anaemia/
Health Navigator. (2015). Iron deficiency. Retrieved from https://www.healthnavigator.org.nz/health-a-z/i/iron-deficiency/
Health Navigator. (2019). Iron overload. Retrieved from https://www.healthnavigator.org.nz/health-a-z/i/iron-overload/
New Zealand Nutrition Foundation. (2018). Iron. Retrieved from https://nutritionfoundation.org.nz/nutrition-facts/minerals/iron
Patient Info. (2016). Folic acid deficiency anaemia. Retrieved from https://patient.info/allergies-blood-immune/anaemia-leaflet/folic-acid-deficiency-anaemia
Patient Info. (2016). Vitamin B12 deficiency and pernicious anaemia. Retrieved from https://patient.info/allergies-blood-immune/anaemia-leaflet/vitamin-b12-deficiency-and-pernicious-anaemia
Sports Dietitians Australia. (n.d.). Iron depletion. [Factsheet]. Retrieved from https://www.sportsdietitians.com.au/factsheets/diets-intolerances/iron-depletion/
World Health Organization. (2001). Iron deficiency anaemia: Assessment, prevention and control. [pdf]. Retrieved from https://www.who.int/nutrition/publications/en/ida_assessment_prevention_control.pdf