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 energy production. 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 ensuring 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, found in animal products, is more easily absorbed by the body, while non-heme iron, found in plant-based foods, is not absorbed as efficiently.
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 iron-rich plant foods, such as legumes, whole grains, and nuts. Phytate content in whole grains 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 or 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 may involve blood tests to measure various markers, including serum ferritin, which reflects the amount of stored iron in the body. Other markers include serum iron, transferrin saturation, and total iron-binding capacity. If you suspect that you may have an iron deficiency, it’s important to speak with a healthcare provider for 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, make sure you are eating enough fibre (aim for 30 g per day) and drinking enough water (around 2 L per day for most people). In addition, you can try adding 1–2 teaspoons of flaxseeds per day and/or 1–2 kiwifruits per day, as both can help relieve constipation. You may also consider switching to a lower-dose supplement; however, keep in mind that this may take longer to correct a deficiency.
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 foods. 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. Therefore, supplementation should be done under the guidance of a doctor or dietitian.
Another effective option is intravenous iron infusions. This is usually the quickest way to correct the issue, so you may want to discuss it with your doctor to see if you’re a suitable candidate. Personally, this would be my go-to option for increasing ferritin stores quickly.
What About Through Food?
While it may not be completely impossible, correcting a deficiency through food alone is one of the least effective methods, and I would not recommend it—especially for those with increased iron needs.
For context, a plant-based menstruating person would need approximately 32 mg of iron per day to slightly exceed their baseline needs. For example, 150 g of tofu contains around 4 mg of iron—and that’s considered one of the richer vegan sources. So, consistently reaching well above 32 mg per day through food alone would be very difficult.
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.
