Iron deficiency is one of the most common issues I see in clinic, especially in Women. If you’ve ever felt exhausted, breathless, foggy, or struggled with hair loss, you’ve probably been told to check your iron.
But what happens when you take iron supplements and your levels still won’t budge? Or worse, when iron makes you feel nauseous, constipated, or inflamed?
Iron metabolism is far more complex than just taking a supplement. There are multiple factors that block absorption, drive depletion, and increase inflammation, making it harder for your body to use iron properly.
If you’ve been struggling with low iron for years, there’s a reason why.
Common Causes of Low Iron
Most people assume iron deficiency is caused by not eating enough iron, but in reality, it’s often an absorption or regulation issue. Here are some of the most common reasons I see in clinic:
1. Low Stomach Acid (Hypochlorhydria)
Stomach acid is essential for iron absorption. Without enough acid, non-haem iron (plant-based iron) doesn’t get broken down properly, and absorption plummets. Low stomach acid is incredibly common in people with:
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Chronic stress
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Gut issues (bloating, reflux, SIBO)
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Long-term use of antacids or PPIs
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H. pylori infections
To support stomach acid, I often recommend using apple cider vinegar or digestive bitters before meals and avoiding large amounts of water with meals, as this can dilute stomach acid.
2. Inflammation & Hepcidin Regulation
One of the biggest drivers of iron deficiency that gets overlooked is inflammation. When the body is inflamed, it produces hepcidin, a hormone that blocks iron absorption and traps iron inside cells. This means even if you're taking iron supplements, your body isn’t actually using it.
Hepcidin is increased in:
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Chronic infections
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Autoimmune conditions (endometriosis, Crohn’s, Hashimoto’s)
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High stress and cortisol dysregulation
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Obesity and metabolic dysfunction
Rather than just supplementing with more iron, I always check inflammatory markers like CRP (C-reactive protein) to get a better picture of what’s going on.
Why Iron Infusions Aren’t Always the Best Option
Many people with low iron are rushed into an iron infusion, but this can be a short-term fix that doesn’t address the real issue.
Iron infusions can increase inflammation, spike CRP levels, and if iron regulation is already impaired, the body may not use it efficiently. Excess iron also feeds pathogenic bacteria and worsens gut dysbiosis.
There are cases where an infusion is necessary, but it should always be part of a bigger strategy that includes fixing absorption and inflammation so iron levels can be maintained long-term.
Why Ferric Iron Isn’t the Best Choice
Not all iron supplements are created equal. Many over-the-counter iron supplements contain ferric iron, which is:
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Harder to absorb
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More likely to cause constipation and nausea
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More inflammatory
Instead, I recommend:
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Ferrous bisglycinate – A gentler, well-absorbed form of iron that’s easier on digestion.
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Lactoferrin or iron glycinate – Better tolerated, especially in people with gut issues.
The Gut-Iron Connection: Why Lactobacillus plantarum 299v Helps
Gut health plays a huge role in iron absorption. Certain probiotics, like Lactobacillus plantarum 299v, have been shown to:
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Improve iron absorption by enhancing uptake in the intestines
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Reduce inflammation that blocks iron metabolism
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Support a healthy gut microbiome, which is critical for overall nutrient absorption
Iron Co-Factors: What Helps You Absorb More Iron?
Iron doesn’t work in isolation—your body needs other key nutrients to absorb and use it properly.
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Vitamin C – Enhances non-haem iron absorption. Adding lemon juice to meals or taking vitamin C with iron supplements helps significantly.
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Copper – Needed to move iron around the body. Found in cashews, sesame seeds, and liver.
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Zinc – Competes with iron for absorption, so I usually recommend taking them at different times of the day.
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B Vitamins – Essential for red blood cell production. B12 is especially important for vegans and vegetarians.
Haem vs Non-Haem Iron: What’s the Best Source?
Iron comes in two forms:
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Haem iron (animal-based) – Found in red meat, liver, poultry, and fish. This form is more easily absorbed.
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Non-haem iron (plant-based) – Found in lentils, spinach, tofu, and nuts, but requires vitamin C for better absorption.
How to maximise absorption from non-haem iron:
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Pair plant-based iron with vitamin C (for example, spinach with lemon juice).
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Soak and sprout legumes to reduce phytates, which block absorption.
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Avoid tea and coffee with meals, as tannins inhibit iron uptake.
Iron, Cancer, and Chronic Inflammation
Iron metabolism is closely linked to cancer risk. Excess iron can fuel oxidative stress and DNA damage, feed pathogenic bacteria, and increase inflammation, which is a major driver of cancer progression.
If someone has cancer or chronic inflammation, I am extra cautious about how iron is supplemented. In these cases, it’s often better to support absorption naturally through diet and gut health rather than relying on high-dose supplements.
Struggling with Low Iron? We Can Help
If you’ve been taking iron supplements but not seeing results, or if you keep needing iron infusions, it’s time to look deeper into the root cause.
At Her Earth Medicine, we help uncover the underlying issues behind iron deficiency, whether it’s:
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Low stomach acid
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Inflammation blocking iron absorption
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Gut issues preventing uptake
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Nutrient imbalances affecting metabolism
If you’re waiting for an appointment, you can start today by:
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Adding vitamin C to your meals to boost absorption
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Checking for gut issues (if you have bloating or food intolerances, this could be affecting your iron levels)
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Switching to a better iron supplement (avoiding ferric iron)
If you're ready for a personalised iron plan, book a consultation at Her Earth Medicine and let’s get your iron levels working properly again.