9 common things that can block iron absorption (and what to do instead)
You’re eating well. You’re trying to get more iron in. Maybe you’ve even added red meat, leafy greens or lentils to your meals... but you still feel tired, foggy, or low on energy.
If this sounds familiar, you’re not alone — and it might not be about what you're missing, but what’s getting in the way.
Iron absorption is affected by what you eat with your meals just as much as what’s in them. And if you’re unknowingly blocking your own iron intake, even the best diet can fall short.
Even some iron-rich foods can be affected by what they’re paired with, especially plant-based sources like tofu, leafy greens or wholegrains. That doesn’t mean they’re bad choices, it just means we can be smarter with how we build our meals.
Let’s break down 9 common iron blockers I see in women who are doing all the “right” things, but still feel flat or drained. And if you missed it, you’ll the top 10 iron-rich foods here.
1. Coffee and black tea
These popular drinks contain polyphenols and tannins, which can significantly reduce iron absorption, especially from plant-based (non-haem) sources.
What to do instead: Wait at least 1 hour after eating an iron-rich meal before having your coffee or tea. Morning coffee is fine, just don’t pair it with your iron supplement or spinach smoothie.
2. Calcium-rich foods or supplements
Calcium competes with iron for absorption in the gut. That means cheese, yoghurt, milk and calcium-fortified products could be interfering if eaten too close to your iron sources.
What to do instead: Try having dairy foods at other meals, or move calcium supplements (or magnesium) to nighttime.
3. High-fibre or bran-heavy meals
Wholegrains and high-fibre cereals are important for gut health and blood sugar regulation, and many also contain non-haem iron. But very high-fibre foods (especially bran-based cereals) also contain phytates, which can reduce how much iron your body absorbs, especially if they’re eaten in large amounts without variety.
What to do instead: Include wholegrains like oats, quinoa and brown rice, but try not to rely too heavily on bran-based cereals every day. Add a vitamin C source (like berries or kiwi) to help improve iron absorption.
4. Soy-based foods
These foods are good sources of plant-based iron, especially in vegetarian or flexitarian diets. But they also contain phytates, which can reduce the absorption of that iron, particularly if they’re your only iron source in a meal.
What to do instead: You don’t need to avoid soy foods — just pair them with vitamin C (like tomato, capsicum or citrus) or rotate with other iron sources for better absorption.
5. Antacids or heartburn meds
Medications that reduce stomach acid (like antacids or PPIs) can lower your ability to absorb nutrients, including iron. Low stomach acid = reduced absorption.
What to do instead: Always speak to your doctor before adjusting meds. But if you’re taking antacids regularly, it’s worth checking your iron status.
6. Too much zinc
Excessive zinc can compete with iron for absorption. If you’re taking high-dose zinc supplements (especially long-term), it might throw off your iron balance.
What to do instead: Most people don’t need extra zinc beyond food. If you're supplementing, make sure it's targeted and not overlapping with your iron needs.
7. Red wine
Like tea and coffee, red wine contains tannins that can reduce iron absorption when consumed with meals.
What to do instead: Enjoy your wine (if it fits your lifestyle), but avoid pairing it with your main iron-rich meals.
8. Eggs
Egg yolks contain a compound called phosvitin that can interfere with iron absorption. While eggs are nutritious, they can make it harder for the body to absorb non-haem iron.
What to do instead: Enjoy eggs, but vary your breakfasts if you’re working on iron levels, or add in a source of vitamin C to help offset.
9. Oxalates (in some leafy greens, beetroot & nuts)
Leafy greens like spinach, as well as beetroot and certain nuts, contain iron, but they also have a compound called oxalates that can bind to iron and reduce its absorption.
What to do instead: These foods are still incredibly beneficial and can absolutely be part of an iron-supportive diet. Just pair them with vitamin C-rich foods (like lemon juice, tomato or citrus) to help boost iron uptake.
It’s not about cutting things out, it’s about timing and food-smart tweaks
You don’t need to give up coffee, oats or dairy to improve your iron. It’s all about how you build your meals and when you include certain foods.
Here are some easy ways to support better iron absorption:
✅ Have your tea or coffee 1 hour after eating
✅ Add capsicum, tomato, berries or citrus to meals with plant-based iron
✅ Space out calcium-rich foods and supplements
✅ Mix up fibre and soy foods with other meals across the day
Final thoughts on iron absorption
If you’ve been working on your nutrition and still feel exhausted or off, iron might be the missing piece — and blockers like these could be quietly getting in your way.
This is exactly what we explore in the Build My Diet assessment, where we uncover what your body might be missing and help you make realistic, personalised changes. And if you’re having trouble getting enough iron, check out this ideal one-day meal plan that contains ~18mg and 128g protein!
Curious about more simple nutrition tips? Join me at Flex Food Life and join my Facebook group community for real, practical advice that fits into your lifestyle!
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