7 science backed ways to increase your iron Levels
1. Add a source of vitamin C
Dietary iron comes in two forms: heme iron, from animal products like meat, and non-heme from plant based sources like beans. Iron from animal foods (heme iron) is absorbed more efficiently than iron from plant foods (non-heme iron), with around 25% of heme iron being absorbed compared to less 17% from non-heme iron.
However, adding a source of vitamin C to plant-based iron sources increases the amount of iron your body absorbs. Vitamin C helps convert the plant based iron from an insoluble ferric state (Fe³⁺) to the soluble ferrous state (Fe²⁺), which is more easily absorbed in the small intestine.
Sources of vitamin C: gauva, kiwi, strawberries, citrus fruit, bell peppers, broccoli, Brussels sprouts, sundried tomato, potatoes (especially with skin on), fresh parsely.
Sources of plant-based iron: kidney beans, white beans, soybeans, chickpeas, lentils, peas, broccoli, kale, Brussels sprouts, mustard greens, chard, spinach, oats, qunioa, teff, sesame seeds (and tahini), pumpkin seeds, flaxseeds, chia seeds, dried apricots, dried figs, blackstrap molasses, moringa.
Examples of plant based iron and vitamin C pairings:
- Oatmeal + strawberries and seeds
- Lentil pasta with spinach + sundried tomatoes and roast peppers
- Bean salad with lemon or lime juice
2. Minimise iron inhibitors
One of the reasons why plant sources of iron are absorbed less easily is because they contain compounds that can block the absorption of iron.
Compounds and food that may reduce iron absorption:
Tannins and polyphenols: tea, coffee, green tea, white tea, cocoa, red wine.
Phytates: wholegrains, beans, legumes, nuts and seeds.
Oxylates: spinach, chard, beans, and nuts
Calcium: dairy (milk, cheese)
Zinc supplements: zinc and iron compete for absorption. Zinc supplementation may reduce iron levels.
A note on eggs – Egg yolks contain a protein called phosvitin that can bind iron and reduce its absorption. However, most evidence for this comes from rat studies, and egg whites have been shown to support iron status in humans. Overall, I believe there’s no need to avoid eating eggs.
How to minimise iron inhibitors:
- Avoid having high calcium foods or tannin rich foods at the same time as iron rich meals.
- Pair your iron rich meals with a source of vitamin C.
- Wait at least 30 minutes before having your tea or coffee after a meal.
- Soaking, sprouting, milling and fermenting reduces phytate levels. For example, sourdough bread (fermented), tempeh (fermented), canned chickpeas (soaked) and sprouted seeds have lower phytate levels.
- Take zinc and iron supplements separately, ideally 4 hours apart. If you are anaemic, be cautious with zinc supplementation.
3. Add allium
Foods from the allium family, such as garlic, onions, shallots, and leeks, can help improve iron absorption. When garlic is crushed, a compound called alliin is converted into allicin, which then forms diallyl sulfide. An animal and in vitro (meaning outside a living organism) study found that diallyl sulfide increased ferroportin, a protein that helps move iron from cells into the bloodstream.
Next time you enjoy an iron rich meal, try adding garlic, onion, shallot, or leek.
Tip: Crush garlic and let it sit for about 10 minutes before cooking to boost its health promoting compounds.
4. Cook with cast iron
Cooking with cast iron cookware can increase the iron content of foods, especially in meat and vegetables (and to a lesser extent in legumes). This extra iron can improve haemoglobin levels and help reduce iron deficiency anaemia.
5. Try the probiotic strain LP299v
Lactiplantibacillus plantarum 299v (LP299V) has been shown to support iron status when supplemented at 10 billion CFUs per day. Research demonstrates that LP299V enhances dietary iron absorption, improves serum haemoglobin and iron markers, and helps reduce common gastrointestinal side effects associated with iron supplementation.
For iron deficiency anaemia, LP299V is most effective when used alongside an iron supplement and vitamin C, which together optimise iron uptake and improve tolerance of iron supplementation.
In iron-deficient female athletes (serum ferritin <30 μg/L), supplementation of LP299V alongside iron, has been shown to improve both iron status and athletic performance.
LP299V may also play a preventative role during pregnancy. When supplemented alongside 4.2 mg of iron until week 35 of gestation or until birth, LP299V has been shown to reduce the risk of developing iron deficiency anaemia in the third trimester of pregnancy. Always follow the guidance of a qualified healthcare practitioner during pregnancy.
6. Consider lactoferrin
Lactoferrin is a protein that can bind to iron and facilitate it’s absorption in the small intestine. Supplementation with lactoferrin has been shown to increase haemoglobin, red blood cell count, ferritin and total iron levels, and additionally decrease inflammatory biomarkers, particulary Interleukin-6.
The dosage of lactoferrin in studies adressing iron deficiency and iron deficiency anaemia was 200 mg per day. Please check with your healthcare provider before supplementing.
Dietary sources of lactoferrin come from cow’s milk, with good options being fermented dairy such as yogurt and kefir. Supplement sources are usually labelled as bovine lactoferrin from cow’s milk, or bovine colostrum.
! Most lactoferrin is sourced from cow’s milk, so it is best avoided if you have a cow’s milk allergy.
7. Optimise your iron supplement
The most common forms of iron used in supplements are iron salts, including ferrous sulfate, ferrous fumarate, and ferrous gluconate. If you are diagnosed with iron deficiency anaemia, you are likely to be prescribed iron in one of these forms.
These iron salts tend to have lower absorption rates and are more likely to cause gastrointestinal side effects including: nausea, constipation, diarrhoea, and abdominal cramps.
A better tolerated option is ferrous bisglycinate. This form is absorbed more efficiently and is generally associated with fewer digestive side effects.
Around 10–15% of iron from ferrous sulfate is absorbed, compared with approximately 25–30% from ferrous bisglycinate.
Speaking from experience, i’d recommend an iron capsule over a liquid formula as iron takes strongly like blood.
References
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