There are many benefits of consuming a plant-based diet that includes reduced risk of many health conditions such as heart disease, diabetes and even cancer (1)(2). However, for a lot of people, transitioning to a plant-based diet can be a little bit scary as there is so much misinformation about what you should be eating. 

It’s important to know that there are some nutrient deficiencies that are more common on a plant-based diet, one of them being iron.. but did you know that you can find iron in many plant-based foods that can be easily consumed in the diet?

In this blog you’ll learn everything you need to know to make sure you’re getting enough iron in the diet so you can be sure you’re doing the plant-based diet the right way!

What is iron and why is it important? 

Iron is an essential mineral needed in the diet. Iron’s main role to help build red blood cells by making a type of protein called haemoglobin that carries oxygen around the body in the blood. It also helps to store oxygen in muscle cells, assists in energy production, and supports the immune system. 

What happens if I’m low in iron?

It’s estimated that approximately 25% of the population is iron deficient aka iron deficiency anaemia (IDA). Iron is most commonly lost in the body through loss of blood, this helps to explain why menstruating women have an increased risk of iron deficiency compared to males and postmenopausal women. 

Symptoms of iron deficiency can vary and includes fatigue, shortness of breath, weakness, cold-sensitivity, dizziness, paleness, impaired brain function and reduced immunity.

Where can I get iron in the diet? 

There are actually two different types of iron found in foods.

Iron found in animal products is 40% haem-iron and 60% non-haem iron, and is typically found in beef, lamb, kangaroo, chicken and fish. Offal products such as liver and kidney are particularly rich in haem-iron. Haem-iron is more easily absorbed by the body (3).

Plant-based sources of iron are 100% non-haem and can be found in wholegrain cereals and breads, dried beans and legumes, dark green leafy vegetables, dried fruits, nuts and seeds. Many breakfast cereals and some breads are also fortified with iron.

Unfortunately, non-haem iron is less bioavailable (less absorbed by the gut), this is believed to be because of what are sometimes referred to as ‘anti-nutrients’ such as phytates, oxalates and polyphenols found in plants that can reduce iron absorption. 

Phytates are one of the most potent anti-nutrients that’s found in whole grains, legumes and nuts - foods that are commonly consumed in a plant-based diet. That’s why the Institute of Medicine stated that iron requirements for vegetarians are 1.8 times higher, compared to iron requirements for nonvegetarians (4).

Interestingly, both haem iron and non-haem iron are absorbed in the gut, however through different mechanisms. Haem-iron is absorbed regardless of our iron levels in the body, that can result in iron overload. It is difficult to remove haem-iron from the body and can result in too much iron in the body that also has complications that include fatigue, weight loss, pain etc. High iron intakes can also affect the absorption of other nutrients such as zinc or calcium – creating further health problems!

On the other hand, non-haem iron can be absorbed when we need it and less absorbed when our iron stores are too high meaning that when you consume only non-haem iron in the diet (eg. plant-based diet) your body adjusts and increases its uptake to suit its needs – cool huh!

What are the best plant-based foods for iron?

Believe it or not Hemp seeds are a great source of iron! Other good sources of plant-based iron include legumes (eg. lentils, pinto beans, black beans), soybeans, tofu, tempeh, cashews, pumpkin seeds, almonds, rolled oats, dark leafy greens (eg. spinach, kale, broccoli), dried fruits (eg. apricots, dates), sundried tomatoes, sesame seeds/tahina paste, fortified cereals/breads, quinoa, and brown rice. 

How much iron do we need? 

There are many factors that dictate how much iron we need such as age, sex, menstruation, and dietary factors. Due to blood loss through menstruation, premenopausal women’s recommended daily intakes (RDI) of iron are much higher than males and postmenopausal women.

Based on the different absorption rates of haem and non-haem iron it is recommended that vegetarians, including vegans, consume 1.8 x (180% in the graph) the RDI for Iron. This means men and postmenopausal women should aim for 14.4 mg/day, premenopausal women consume 32.4 mg/day and 48.6 mg/day for pregnant women (9).

https://www.nrv.gov.au/nutrients/iron 

How can I increase iron absorption on a plant-based diet?

Vitamin C can help to enhance absorption of non-haem iron by a sixfold in those who have low iron stores. Vitamin C facilitates the conversion of Fe3+ (ferric) to Fe2+ (ferrous) iron, the form in which iron is best absorbed (6)(7).

The best sources of vitamin C include citrus fruits (eg. lemons, oranges), capsicums, tomatoes, broccoli, kiwi fruit, strawberries, papaya, apricots, cauliflower and pineapple. The good news is that many vegetarians typically have high intakes of vitamin C from a wide variety of fruit and vegetables!

How do I know if I’m iron deficient?

The best way to know is to get a blood test with your doctor that can easily identify iron deficiency. Your doctor may prescribe an iron supplement if you are very low.

There are also many other reasons that people may be at risk of iron deficiency that include:

• Babies given cow’s or other milk instead of breastmilk or infant formula
• Toddlers, particularly if they drink too much cow’s milk
• Teenage girls
• Menstruating women, especially those who have heavy periods
• Women using an IUD (because they generally have heavier periods)
• Pregnant women
• Breastfeeding women
• Poor diets (eg. eating disorders, alcoholics, fad diets)
• Aboriginal Australians
• Athletes in training (particularly females)
• Regular blood donors
• People with conditions that predispose them to bleeding, such as gum disease or stomach ulcers, polyps or cancers of the bowel
• People with chronic diseases such as cancer, auto-immune diseases, heart failure or renal (kidney) disease
• People taking aspirin as a regular medication
• People with Coeliac disease
• Older Population
• Gastrointestinal blood loss (eg. colorectal cancer or genitourinary diseases)
• People who take excessive zinc or calcium supplements (8)

So, what's the bottom line?

Iron is such an important part of the diet and a deficiency can result in many complications, most commonly fatigue. It is definitely possible to get enough iron from a plant-based diet when it’s done right. Consuming plant-based foods rich in iron (such as hemp seeds) and vitamin C rich foods is a great way to avoid iron deficiency. If you experience fatigue or other iron deficiency symptoms, it’s best to discuss with your health professional to rule out iron deficiency as a potential cause. 

If you have any questions or need support with your health, feel free to email our head nutritionist Ben at ben@13seeds.com.au 

Disclaimer: 

This article does not constitute medical advice and does not take into consideration your personal circumstances. Please see your medical professional before implementing the above.

References:

1. https://pubmed.ncbi.nlm.nih.gov/26853923/
2. https://pubmed.ncbi.nlm.nih.gov/25915002/
3. https://pubmed.ncbi.nlm.nih.gov/9063021/
4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6367879/
5. https://www.abs.gov.au/ausstats/abs%40.nsf/lookup/95e87fe64b144fa3ca2568a9001393c0
6. https://pubmed.ncbi.nlm.nih.gov/6764713/
7. https://pdf.usaid.gov/pdf_docs/pnacb908.pdf
8. https://www.betterhealth.vic.gov.au/health/ConditionsAndTreatments/iron
9. https://www.nrv.gov.au/nutrients/iron