Dr Gemma Sampson · 46. Plant based sources of iron: Ask a sports dietitian

Dale asked: My blood tests show that I am anaemic. I don’t like eating meat and am not a huge fan of eating eggs. What foods should I eat more of to help increase absorption and help manage fatigue?

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What does iron do?

Iron plays an important role in oxygen transport and is a key component in red blood cells. If you are low in iron are you might feel lethargic, really tired and lacking in energy or might be easily exhausted with simple tasks. For athletes, low iron stores can mean you don't get the most out of training and underperform in competition.

How much iron do we need?

Iron recommendations vary between countries, according to age and gender, with women needing more until menopause sets in.

Australian iron recommendations are 8mg per day for men and 18mg daily for women

Inadequate iron intake is more prevalent in females than males. In Australia the latest national nutrition & physical activity survey (2011) showed that one in four women (23%) don't eat enough iron - compared to one in thirty men.

Bioavailability of plant based iron

Bioavailability is a measure of how much iron is absorbed and available for the body to use. Many factors in food can influence this - some positively, others negatively. Tannins found in tea can reduce the amount of iron available, while vitamin C in fruits and vegetables can increase the amount that is available.

There are two kinds of iron - haem iron and non-haem iron. Plant-based sources of iron fall under the latter category which aren't absorbed or quite as readily available as the haem sources which are animal based.

Since plant-based iron (non-haem) isn't as bioavailable, people following a vegetarian or vegan diet may need about 1.8 times more iron which means around 14.4 - 15.7mg for men and 26.7 - 32mg of iron for women.

Similarly, research shows that plant based athletes may need 30-70% more iron than the average person depending on the type, intensity and amount of training they do. I've seen a number of my plant based athletes need to take an iron supplement all year long in order to avoid anaemia. It’s worth having getting your iron status checked regularly to avoid iron deficiency and promote peak performance.

When to supplement?

If you've had a blood test that has shown you are anaemic and your iron levels are too low, then this is an occasion where we would consider using an iron supplement to help bump you up to normal levels, while increasing the iron sources in your diet.

Ideally the supplement would be a temporary solution, which is why the regular tests can be helpful to see what happens when you stop. I've seen athletes - particularly the plant based athletes - who need to take an iron permanently because they aren't able to get enough from their diet to meet their needs otherwise.

We would always explore to see if there is something else going on to keep your iron levels low - is it low dietary intake? or is there something else going on that limits absorption. Undiagnosed coeliac disease is an example of where we would see low iron levels - even if the diet is high in iron sources.

If a blood test shows that your iron stores are low and you are anaemic - this is a time where you will need to use a supplement to help bring those levels up faster. In extreme cases, I've seen some athletes need to get an iron infusion because their levels were so low!

We can then work on increasing the iron in your actual diet to help bump up how much you are able to absorb, and then play around with timing of certain foods as somethings like tea or coffee will reduce absorption of the iron in your diet.

Goal Men: 8mg per day women 14-18mg per day.

Different kinds of iron containing foods

When comparing foods it is always useful to compare the 100g as well as a serving to see is that realistic. For example, when I was doing research into plant based iron rich foods it was interesting to discovery just how high seeds, herbs and spices can be in iron.

For example 100g of cumin seeds has 66mg of iron, 100g tumeric powder has 55mg of iron and 100g of poppy seeds has 11mg of iron...

However they aren' t realistic portions! A more realistic portion might be a teaspoon or less - which typically will have less than 1mg iron it.

Which from a plant based perspective, is yet another reason why we need diversity in our diet to get lots of different sources in throughout the day and week.

If we start by comparing some animal sourced foods for reference

Iron in 100g foods

100g Rump steak - 2.9mg
100g egg - 1.2mg
100g chicken breast - 1.1mg
100g salmon - 1mg
100g Pork (no fat) - 1mg

Iron per serving

One 150g lean beef steak (150g) - 4.3mg
Two pork chops (160g) - 1.6mg
Two large (60g) eggs - 1.4mg
One large chicken breast (135g ) - 1.4mg
One salmon fillet (140g) - 1.4mg

Swapping foods

eg red lentil pasta - actually has the same amount of iron as normal wheat pasta!
Normal pasta - 80g dry weight pasta is a 'normal portion'
80g of wheat pasta - (3.6mg per 100mg )
80g lentil pasta (3.6mg per 100mg)
Gluten free pasta made with rice and corn - only has 0.9mg iron

Plant based iron sources

100mg tofu - 2.1mg - would need to eat about 250g block per meal to get equivalent to steak
1 cup edamame beans ( 1 cup 155g) - 3.5mg
3 dried apricots (24g - 0.7mg)
Nori seaweed- 2 sheets (6g) - 0.7mg
80g serve (dry) wheat or lentil pasta - 3.6mg
1 cup cooked (150g) kidney beans = 3mg
1 tbsp sesame seeds - 0.6mg
1 tbsp pumpkin seeds - 0.6mg
1 tbsp poppy seeds - 0.9mg