How Can I Increase Iron Absorption?

Without sufficient iron, we can develop unwanted conditions and symptoms.

Here's the current RDA (Source: U.S. Department of Health & Human Services)

Age Male Female Pregnancy Lactation
Birth to 6 months 0.27 mg* 0.27 mg*
7–12 months 11 mg 11 mg
1–3 years 7 mg 7 mg
4–8 years 10 mg 10 mg
9–13 years 8 mg 8 mg
14–18 years 11 mg 15 mg 27 mg 10 mg
19–50 years 8 mg 18 mg 27 mg 9 mg
51+ years 8 mg 8 mg


But simply consuming iron-rich foods or supplements may not be enough; we must ensure that our bodies are efficiently absorbing this crucial nutrient.

This article will delve deep into the science and strategies of enhancing iron absorption. 

What are the Different Forms of Dietary Iron

In our daily diet, we encounter two primary forms of iron: heme and non-heme iron, each distinguished by its unique source and absorption characteristics.

Heme iron is derived from hemoglobin and myoglobin, the oxygen-carrying proteins in animal-based foods, such as meat, fish, and poultry.

The unique advantage of heme iron lies in its structure. Structurally similar to human hemoglobin, studies demonstrate that heme iron is readily recognized and absorbed in the intestines. In fact, our bodies can absorb up to 40% of the heme iron we consume. This makes heme iron a valuable source for maintaining adequate iron levels, particularly for those at risk of having low iron.

Non-heme iron, on the other hand, is found in plant-based foods like grains, nuts, seeds, legumes, and iron-fortified products.

Unlike heme iron, the non-heme form is not inherently linked to proteins and is present in a variety of forms, including iron salts and iron chelates. The human body tends to absorb non-heme iron less efficiently, typically around 2-20%. Its absorption is influenced by several dietary factors, including the presence of certain nutrients, such as vitamin C, which can significantly enhance its bioavailability.

The difference in the absorption rates of these two forms of iron is tied to their inherent biochemistry.

Heme iron is absorbed by a specific pathway that allows it to bypass factors that might inhibit the absorption of non-heme iron.

Conversely, non-heme iron is absorbed via a different pathway, one more susceptible to influence by various dietary factors. This pathway involves the reduction of ferric iron (Fe3+) to ferrous iron (Fe2+), which can be facilitated by consuming vitamin C.

healthy microbiome

What if I'm not absorbing enough iron from my food?

If you find it challenging to obtain sufficient iron from dietary sources, supplementation may be a viable alternative. Iron is crucial for various physiological processes, including oxygen transport and energy production.

Before starting any supplementation, consult a healthcare professional for an accurate diagnosis of your iron levels. Excess iron can be toxic and lead to serious health conditions.

Once a deficiency is confirmed, consider supplements that prioritize bioavailability. Poorly absorbed iron may lead to gastrointestinal distress and limited efficacy. Bioavailable forms of iron ensure better absorption and utility within the body.

Which foods contain the most iron?

Meat Products

Food Item Portion Size Iron (mg/portion) Iron (mg/100g)
Ox Kidney Average portion in gravy (112g) 10.8 9.0
Black Pudding 1 Portion (75g) 9.3 12.3
Lambs liver 1 portion (100g) 7.7 7.7
Rump Steak (grilled) Medium (144g) 5.2 3.6
Liver Pate Starter sized portion (80g) 4.7 5.9
Lambs Kidney Average portion (35g) 4.0 11.2
Minced Beef Medium portion (140g) 3.8 2.7
Duck Medium portion, meat only (100g) 2.7 2.7
Sardines 1 average portion canned (100g) 2.3 2.3
Roast Beef - Topside 2 thick slices (90g) 2.3 2.6
Oxtail Soup Medium portion (220g) 2.2 1.0
Pheasant Average portion (100g) 2.2 2.2
Steak & Kidney Pie Individual pie (160g) 2.1 1.3
Lamb Chop Average chop (100g) 2.1 2.1
Mackerel 1 medium smoked mackerel (150g) 1.8 1.2
Roast Beef - Sirloin 2 thick slices (90g) 1.7 1.9
Tuna, canned in oil 1 small can (100g) 1.6 1.6
Roast Leg Lamb 3 slices (90g) 1.6 1.8
Beef Sausage 2 sausages (80g) 1.4 1.8
Corned Beef 1 thick slice (50g) 1.2 2.4
Pork Chop Average chop (100g) 1.2 1.2
Roast Pork Medium portion (90g) 0.9 1.0
Beefburger 1 Burger (80% beef) (36g) 0.9 2.5
Turkey Breast fillet (100g) 0.8 0.8
Chicken Average chicken breast (100g) 0.8 0.8
Tongue 1 average slice (25g) 0.7 2.6
Salmon Average salmon steak (100g) 0.5 0.5


Non Meat Products

Food group Food Portion size Iron (mg/portion) Iron (mg/100g)
Beans and Pulses Soya beans (boiled) 100g 3.0 3.0
Green & brown lentils 1 tablespoon (40g) 1.4 3.5
Butter beans Average portion (90g) 1.3 1.5
Red Lentils 1 tablespoon(40g) 1.0 2.4
Baked beans 1 tablespoon (40g) 0.6 1.4
Peas 1 tablespoon (40g) 0.6 1.5
Kidney beans 1 tablespoon (30g) 0.6 2.0
Chick peas 1 tablespoon (35g) 0.5 1.5
Hummus 1 tablespoon(20g) 0.4 1.9
Meat Substitutes Tofu (steamed & fried) Average portion (140g) 4.9 3.5
Tofu (steamed only) Average portion (140g) 1.7 1.2
Eggs Eggs 1 average (50g) 1.0 1.9
Dried Fruit Prunes 6 stewed (60g) 1.6 2.6
Raisins 1 tablespoon (30g) 1.1 3.8
Figs 1 dried (20g) 0.8 4.2
Apricots 1 dried (8g) 0.3 3.4
Dates 1 dried (15g) 0.2 1.3
Nuts & Seeds Tahini paste 1 heaped teaspoon (19g) 2.0 10.6
Cashew nuts Roasted salted bag (25g) 1.6 6.2
Sesame seeds 1 tablespoon (12g) 1.2 10.4
Sunflower seeds 1 tablespoon (16g) 1.0 6.4
Pine nuts 1 tablespoon (10g) 0.6 5.6
Peanut Butter 1 tablespoon(20g) 0.5 2.5
Almonds 6 whole (13g) 0.4 3.0
Brazil nuts 3 whole (10g) 0.3 2.5
Hazelnuts Approx handful (10g) 0.3 3.2
Peanuts 10 whole (13g) 0.3 2.5

The Role of Vitamin C in Enhancing Iron Absorption

Studies show that Vitamin C, also known as ascorbic acid, is a potent enhancer of non-heme iron absorption because of its ability to convert iron into a form that is easier for the body to absorb.

Non-heme iron, which is found in plant-based foods and iron-fortified products, is predominantly present as ferric iron (Fe3+), an insoluble and thus less bioavailable form.

Vitamin C acts as a powerful reducing agent, converting ferric iron into ferrous iron (Fe2+), a more soluble and bioavailable form. This transformed iron is easier for the intestinal cells to absorb, ensuring that more iron from our diet makes it into our bloodstream.

Not only does Vitamin C aid in the absorption of iron from food, but it also counteracts the inhibitory effects of certain substances like phytates and polyphenols found in plant foods, which can bind to iron and hinder its absorption.

Including vitamin C-rich foods in your meals, especially those containing non-heme iron sources, can therefore significantly boost your iron absorption. Citrus fruits, berries, bell peppers, broccoli, and leafy green vegetables are all excellent sources of Vitamin C.

For example, pairing a spinach salad (high in non-heme iron) with orange slices (rich in Vitamin C) can lead to a significant improvement in the iron absorbed by your body.

Beneficial Food Combinations for Optimal Iron Absorption

Optimizing iron uptake can be achieved by combining certain foods that enhance iron absorption.

Here are some beneficial food combinations that may help maximize iron absorption:

  1. Iron-rich foods with vitamin C sources: Vitamin C enhances iron absorption. Pair iron-rich foods such as spinach, kale, or lean red meat with vitamin C sources like citrus fruits (oranges, grapefruits), strawberries, bell peppers, or tomatoes.

  2. Legumes with vitamin C-rich vegetables: Legumes, such as lentils, chickpeas, or kidney beans, are good sources of iron. Combine them with vitamin C-rich vegetables like broccoli, Brussels sprouts, or bell peppers to improve iron absorption.

  3. Iron-fortified cereals with citrus fruits: Iron-fortified cereals provide a good amount of iron. Pairing them with citrus fruits like oranges or grapefruits can significantly enhance iron absorption due to the high vitamin C content.

  4. Iron-rich foods with fermented foods: Fermented foods like yogurt, kefir, or sauerkraut contain probiotics that can enhance iron absorption. Pairing them with iron-rich foods such as lean meat, fish, or leafy greens can be beneficial.

  5. Meat with vegetables high in beta-carotene: Beta-carotene, found in vegetables like carrots, sweet potatoes, or spinach, can improve iron absorption. Combine these vegetables with lean meats like chicken or turkey to increase iron uptake.

  6. Iron-rich foods with citric acid: Citric acid, found in citrus fruits and some fruits like pineapple, can boost iron absorption. Pair iron-rich foods such as beef, poultry, or fish with citrus fruits or add a squeeze of lemon or lime juice to enhance iron absorption.

Foods to Avoid: Inhibitors of Iron Absorption

While there are certain foods and nutrients that can enhance iron absorption, others can inhibit it, making it more difficult for your body to effectively absorb and utilize this essential mineral.

  1. Phytates: Phytates, or phytic acid, are found in many whole grains, nuts, seeds, legumes, and some fruits and vegetables. They can bind to non-heme iron in your digestive tract, inhibiting its absorption. Soaking, sprouting, or fermenting these foods can help reduce their phytate content and improve iron absorption.

  2. Polyphenols: Polyphenols are a type of antioxidant found in certain fruits, vegetables, legumes, coffee, tea, and wine. They can interfere with non-heme iron absorption. While they are beneficial for their antioxidant properties, you may want to avoid consuming these foods and drinks alongside iron-rich meals.

  3. Calcium: Although calcium is an essential nutrient, it can inhibit the absorption of both heme and non-heme iron if consumed in large amounts at the same meal. This doesn't mean you should avoid calcium-rich foods, but rather you might want to consume them separately from iron-rich meals.

  4. Certain Proteins: Some proteins found in foods like soy, dairy, and eggs can also interfere with iron absorption. It may be beneficial to consume these foods apart from iron-rich meals.

  5. Tannins: Found in tea and some types of coffee, tannins can inhibit iron absorption. It's advisable to enjoy these beverages between meals rather than with them.

How Cooking Methods Affect Iron Bioavailability

The cooking method you use can have an impact on the bioavailability of iron in foods. Here are some ways different cooking methods can affect iron:

  1. Boiling: Boiling foods, especially vegetables, can lead to significant losses of water-soluble nutrients, including iron. When vegetables are boiled, some of the iron may leach into the cooking water, reducing its availability. To minimize iron loss, you can utilize the cooking water for soups, stews, or sauces to retain the nutrients.

  2. Steaming: Steaming is a gentle cooking method that helps preserve nutrients, including iron. It is a preferred method for cooking vegetables as it reduces nutrient loss compared to boiling. Steaming allows the food to retain its natural juices and nutrients, including iron.

  3. Stir-frying: Stir-frying involves quickly cooking foods at high heat. This method helps retain the texture, flavor, and nutrients of vegetables while minimizing nutrient loss. Since the cooking time is short, iron loss is generally minimal, resulting in better iron bioavailability.

  4. Grilling: Grilling or broiling meats can lead to the formation of a crust on the surface, which helps retain the iron content. However, it's important to avoid overcooking, as excessive heat and prolonged cooking times may lead to iron loss. To preserve the iron content, cook meats until they are just done and avoid charring or burning them.

  5. Fermentation: Fermentation is a traditional food preservation method that can enhance iron bioavailability. Fermented foods, such as sourdough bread, tempeh, or sauerkraut, undergo a fermentation process that can break down phytates, which are compounds that can hinder iron absorption. By reducing phytate levels, fermentation can improve iron bioavailability.

  6. Acidic ingredients: Adding acidic ingredients, such as lemon juice or vinegar, to iron-rich foods can enhance iron absorption. The acid helps to break down phytates and enhances the release of iron during digestion, thereby improving iron bioavailability.

The Importance of Gut Health in Iron Absorption

The health of our gut, or gastrointestinal tract, plays a vital role in the absorption of iron and other nutrients. A balanced gut microbiome - the community of microorganisms living in our intestines - and a well-functioning digestive system are key to ensuring we are effectively absorbing iron from the food we eat.

  1. Role of the Gut Microbiome: Certain gut bacteria may promote iron absorption. Some types of beneficial bacteria are capable of converting dietary iron into a more absorbable form. In contrast, an imbalanced gut microbiome can negatively impact nutrient absorption, including iron.

  2. Intestinal Health: Inflammation or damage to the intestines can hinder the body's ability to absorb iron and other nutrients.

  3. Stomach Acid: Hydrochloric acid in the stomach plays a crucial role in iron absorption. It converts dietary iron to a form that is more readily absorbed in the intestine. Conditions that reduce stomach acid, such as long-term use of antacids, can therefore impede iron absorption.

  4. Importance of Fibre: A diet rich in fiber supports a healthy gut by promoting regular bowel movements and feeding beneficial gut bacteria. However, extremely high-fiber meals may inhibit iron absorption slightly. Therefore, it's all about balance - ensuring you get plenty of fiber to maintain gut health while also being mindful of your iron intake.

  5. Probiotics and Prebiotics: These can help maintain a healthy gut microbiome, potentially enhancing iron absorption. Probiotics are beneficial bacteria, while prebiotics are food for these bacteria.

When to Take Supplements for Maximum Iron Absorption

If you're considering taking iron supplements to boost your iron levels, it's important to understand the best ways to maximize absorption. When and how you take these supplements can make a significant difference in their effectiveness.

  1. Timing: Iron supplements are best taken on an empty stomach to maximize absorption. If possible, take them one hour before meals or two hours after meals. However, some people may experience stomach discomfort when taking iron on an empty stomach. In such cases, taking the supplement with a small amount of food can help, though this might slightly reduce the amount of iron absorbed.

  2. Pair with Vitamin C: As discussed earlier, Vitamin C enhances iron absorption. Consider taking your iron supplement with a glass of orange juice or another source of Vitamin C to optimize iron uptake.

  3. Avoid Certain Foods and Drinks: Try not to take iron supplements with dairy products, coffee, tea, or antacids, as these can inhibit iron absorption.

  4. Spacing out other Supplements: Other minerals like calcium, zinc, and magnesium can interfere with iron absorption. If you're taking these supplements, it's best to space them out from your iron supplement.

  5. Frequency: Some people may benefit from taking smaller doses of iron multiple times a day rather than a single large dose.

  6. Consistency: Regularity is key. Make taking your supplement part of your daily routine to ensure you don't forget it.

Personalising Your Diet for Enhanced Iron Absorption

Every individual's body is unique, and so is their dietary needs and responses. To enhance iron absorption effectively, it's important to personalize your diet based on your individual lifestyle, dietary preferences, and health status.

  1. Understanding Your Iron Needs: Different people have different iron needs. For instance, women, particularly during pregnancy or menstruation, and athletes may require more iron. Vegetarians and vegans also need to pay extra attention to their iron intake, as plant-based iron is not as readily absorbed as iron from animal sources.

  2. Dietary Preferences: If you follow a vegetarian or vegan diet, focus on consuming plenty of iron-rich plant foods, like lentils, tofu, quinoa, and spinach. Pair these with vitamin C-rich foods to enhance iron absorption. If you eat meat, opt for lean meats like chicken and fish, which are good sources of easily absorbable heme iron.

  3. Managing Dietary Inhibitors: If you consume foods or beverages that can inhibit iron absorption like coffee, tea, or calcium-rich foods, try to have them in between meals rather than with your iron-rich meals.

  4. Cooking Methods: Consider cooking methods that can enhance iron bioavailability, such as cooking in a cast-iron skillet, and methods that can decrease inhibitors of iron absorption, like soaking and sprouting beans and grains.

  5. Lifestyle Factors: Regular exercise can help stimulate appetite and potentially improve your body's demand for iron, thereby boosting absorption. Also, ensure to maintain a healthy gut as it plays a crucial role in nutrient absorption.

  6. Regular Check-ups: Regular blood tests can help monitor your iron levels and adjust your diet or supplements as needed under the guidance of a healthcare professional.

 Tips to get enough iron

Here are some concluding tips:

  1. Choose Iron-Rich Foods: Opt for foods naturally abundant in iron like lean meats, legumes, and leafy green vegetables.

  2. Prioritise Bioavailable Sources: Favor animal-based iron sources for better absorption.

  3. Combine Iron with Vitamin C: Increase iron absorption by consuming it alongside Vitamin C-rich foods.

  4. Cooking Methodology: Utilise cooking methods, such as using a cast-iron skillet, that can fortify foods with iron.

  5. Avoid Inhibitors: Separate the consumption of iron inhibitors like calcium and certain teas from iron-rich meals.

  6. Fortified Foods: Select foods fortified with iron like cereals and plant-based milks.

  7. Portion Control: Follow appropriate portion sizes to include a variety of nutrients, including iron.

  8. Frequent Monitoring: Undertake regular medical tests to keep track of your iron levels.

  9. Consult a Healthcare Professional: Seek professional guidance if unable to meet iron needs through diet alone.

  10. Balanced Diet: Maintain a well-rounded diet that includes a range of essential nutrients alongside iron.

FAQs about Iron Absorption

What is iron absorption?

Iron absorption is the process by which the iron in food or supplements is absorbed from the digestive tract into the bloodstream, where it is used for various vital functions such as the production of red blood cells.

What factors affect iron absorption?

Several factors can affect iron absorption. These include the type of iron in your diet (heme or non-heme), the presence of other dietary components that can enhance or inhibit iron absorption (such as vitamin C or phytates), your overall gut health, and individual health status (such as whether you have an iron deficiency or certain health conditions).

How can I enhance my iron absorption?

To enhance iron absorption, you can pair iron-rich foods with foods high in vitamin C, avoid consuming iron inhibitors like coffee or calcium-rich foods with your meals, and maintain good gut health. For those with low iron, an iron supplement may be recommended by a healthcare professional.

What's the difference between heme and non-heme iron?

Heme iron is found in animal-based foods and is more readily absorbed by the body. Non-heme iron is found in plant-based foods and iron-fortified products, and while it is still an important source of iron, it is typically less easily absorbed than heme iron.

Can taking iron supplements on an empty stomach improve absorption?

Yes, iron supplements are generally absorbed best when taken on an empty stomach. However, this may cause stomach discomfort for some people. If you experience this, taking the supplement with a small amount of food can help, though it may slightly reduce absorption.

How does gut health impact iron absorption?

A healthy gut is crucial for optimal iron absorption. Good gut health ensures that iron is properly absorbed into the bloodstream from the digestive tract. Certain gut bacteria can even promote iron absorption. Conversely, gut inflammation or damage can inhibit the absorption of iron and other nutrients.