Blog Post

How To Get Enough Iron On A Plant-Based Diet

Iron is an essential nutrient that plays a vital role in the body, including transporting oxygen to cells and tissues, supporting immune function, and aiding in the production of energy. However, individuals following a vegan or vegetarian diet can be more at risk of developing an iron deficiency due to the lower bioavailability of iron in plant-based sources. In this blog post, I’ll discuss how to ensure you’re meeting your iron needs on a plant-based diet.

Iron Requirements

The recommended daily intake (RDI) for iron is 18 mg per day for premenopausal women and 8 mg per day for men and postmenopausal women. However, it’s important to note that not all iron is created equal. There are two types of dietary iron: heme iron and non-heme iron. Heme iron is found in animal products and is more easily absorbed by the body, while non-heme iron is found in plant-based foods and is not as easily absorbed.

Haem Iron

  • Found only in animal products such as meat and fish
  • Absorbed well by the body → approximately 15-35% of what we consume is absorbed during digestion
  • Absorption is not impacted by other dietary factors

Non-haem Iron

  • Found in both animal products and plant-based foods
  • Not as well absorbed by the body (approximately 2-20% of what we consume is absorbed during digestion)
  • Absorption can be affected by other factors and foods consumed at the same time

To ensure adequate iron intake, vegans and vegetarians should aim for a daily intake of 1.8 times the RDI for non-heme iron, which equates to 32 mg per day for premenopausal women and 14 mg per day for men and postmenopausal women.

Below is a summary of the daily requirements for vegans at 1.8x the values provided in the Nutrient Reference Values for Australians and New Zealanders.

Plant-Based Sources Of Iron

There are plenty of plant-based sources of iron, and by incorporating a variety of these foods into your diet, you can easily meet your daily iron requirements. Some of the best plant-based sources of iron include:

  • Legumes such as lentils, chickpeas, and black beans
  • Leafy greens like spinach, kale, and collard greens
  • Whole grains like quinoa, brown rice, and oats
  • Nuts and seeds, including pumpkin seeds, hemp seeds, and almonds
  • Dried fruits like apricots, prunes, and raisins
  • Soy foods such as tofu, TVP & tempeh
  • Some mock meats

Optimising Iron Absorption

There are many dietary factors that can either increase (enhancers) or decrease (inhibitors) our body’s ability to absorb iron from plant-based foods.

Inhibitors

The main inhibitor is phytates or phytic acid which is often referred to as an ‘anti-nutrient’ because it binds to minerals such as iron preventing their absorption. Unfortunately, phytates are abundant in many of the iron-rich plant foods such as legumes, whole grains and nuts. Phytate content in wholegrains can be reduced during processing however nutrients such as iron and zinc are often reduced as well. Other ways to decrease phytates include leavening bread and soaking and sprouting legumes, grains, and seeds.

Other inhibitors include polyphenols (which are found in tea, coffee, cocoa, and red wine) and other minerals including calcium and zinc which compete for absorption.

Enhancers

The most effective way to increase the amount of iron the body absorbs from the diet is to pair iron-rich meals with a source of vitamin C. In fact, consuming 50mg of vitamin C with your meals can increase iron absorption by 3 to 6-fold.

This may look like this:

  • ½ medium capsicum – 210mg
  • 1 grapefruit – 93mg
  • 1 kiwifruit – 86mg
  • 1 orange – 68mg
  • 6 medium strawberries – 30mg
  • ½ cup steamed broccoli – 26mg
  • 1 medium baked potato – 22mg
  • 1 tbsp lemon or lime juice – 7mg

Other dietary factors which increase iron absorption include:

  • Food additives such as citric, malic, and lactic acids
  • Vitamin A and beta-carotene which is high in dark leafy greens, orange fruits/vegetables such as carrots, sweet potatoes and apricots

Iron Deficiency

Iron deficiency is one of the most common nutritional deficiencies worldwide, and it can lead to a variety of symptoms, such as fatigue, weakness, headaches, pale skin, and shortness of breath. Severe iron deficiency can even result in anemia, a condition where the body doesn’t have enough red blood cells to carry oxygen to tissues and organs.

Diagnosing iron deficiency can involve blood tests to measure various markers, including serum ferritin, which is a measure of stored iron in the body. Other markers include serum iron, transferrin saturation, and total iron-binding capacity. If you suspect you may have an iron deficiency, it’s important to speak with a healthcare provider to get a proper diagnosis.

Treating Iron Deficiency

If you do have a diagnosed deficiency, one of the most accessible and effective options would be a high-dose iron supplement (100-200mg/day) such as Ferro Grad C or Maltofer.

Although, many people complain of gastrointestinal issues when taking these types of supplements with the most common being constipation and black, tarry stools.

In that case, you could opt for a product like Maltofer iron which is still a high dose (100mg/serve) but is formulated to be less harsh on the gut (iron polymaltose instead of ferrous iron).

To reduce the risk of constipation you can also make sure you are eating enough fiber (aim for 30g per day) and drinking enough water (for most people 2L per day). In addition, you can try adding in 1-2 tsp of flaxseeds per day and/or 1-2 kiwi fruits per day, as both of these can help improve constipation. You can reduce to a lower dose supplement but bear in mind that it will take longer to correct a deficiency if you do this.

Due to the body’s ability to tightly regulate iron absorption from food sources, there is no evidence of adverse effects from consuming high amounts of iron from plant-based food sources. However, over-supplementation of iron can lead to excess iron accumulation in the body which can be very harmful. Possible side effects include constipation, diarrhoea, vomiting, nausea, liver dysfunction, and increased inflammation in the body. So supplementation should be done under the advice of a doctor or dietitian.

Another effective option would be intravenous iron infusions. This would usually be the quickest way to rectify the issue so you may want to discuss this with your doctor to see if you are a suitable candidate. Personally, this would be my go-to option to increase ferritin stores quickly.

What About Through Food?

Whilst it may not be completely impossible, rectifying a deficiency through food alone is one of the most ineffective methods, and I would not recommend it. Especially for those with elevated iron needs.

For context, a plant-based, menstruating person would need ~32mg per day to be just over their baseline needs. 150g tofu contains ~4mg of iron and that is one of the richer sources of iron as a vegan. So to consistently get significantly over 32mg per day would be very difficult through food alone.

Iron-Rich Day Of Eating

Below is an example of a very iron-rich day of plant-based eating, of course, most people will not need 50mg of iron per day. However, it is a good way to show lots of different options for building a higher iron intake.

By Leah Higl

Leah is an accredited practising dietitian from Brisbane. She also competes as an under 75kg powerlifter with Valhalla Strength Brisbane. As both an athlete and dietitian, she spends much of her time developing her knowledge and skills around sports nutrition, specifically for strength-based sports. Although, she works with a range of athletes from triathletes to combat sports and powerlifting. Leah also follows a plant-based diet and her greatest passion is fuelling vegan/vegetarian athletes and proving that plant-based athletes can be just as competitive as their non-vegan counterparts.​