Iron deficiency is one of the most common nutrient deficiencies worldwide. Yet despite how common it is, it’s also one of the most misunderstood. One of the biggest mistakes I see is people assuming that because iron deficiency is common and causes so many symptoms, they should automatically start taking an iron supplement.

But before you start taking iron supplements, we need to establish whether you are actually deficient and, just as importantly, understand why your iron levels are low in the first place. So let’s get into it!

Benefits of Iron

Most people know iron is important, but very few people understand just how many jobs it performs within the body.

Iron is known for its role in producing haemoglobin, a protein found inside red blood cells. Haemoglobin carries oxygen from your lungs to every tissue, organ and cell in your body. Without enough iron, your body struggles to produce healthy red blood cells and transport oxygen effectively. This is why low iron can leave you feeling exhausted, weak and out of breath.

However, iron does a lot more than help produce healthy red blood cells!

Iron is also involved in:

• Energy production
• The production of neurotransmitters such as dopamine and serotonin which impact your mood and motivation
• Thyroid hormone production
• Collagen production

And this is why there are so many symptoms of an iron deficiency. We’ll run through them now:

What Are The Symptoms Of Low Iron, or An Iron Deficiency?

The most commonly recognised symptoms of iron deficiency include:

• Fatigue
• Dizziness or lightheadedness
• Pale skin
• Feeling cold all the time
• Weakness
• Shortness of breath

But a lot of people are surprised to learn that iron deficiency can cause a wide range of other symptoms too.

Unexpected Signs Of Low Iron

Some of the lesser-known symptoms of iron deficiency include:

• Hair thinning
• Increased hair shedding (so if you notice your hair is falling out a lot more, we need to rule out this deficiency)
• Anxiety
• Brain fog
• Difficulty concentrating
• Headaches
• Brittle nails
• Restless legs syndrome
• Reduced exercise performance
• Poor recovery after exercise
• Slow wound healing

Many of these symptoms develop gradually over time, which makes them easy to dismiss or blame on stress, a busy lifestyle or getting older. A lot of my clients will say they were fine before, but over the past few years their energy levels just seem to have dipped. I’ll have so many mothers blaming the symptoms on having young children too. (Yes, they might be making you tired, but you could also be iron-deficient!)

Can an Iron Deficiency Cause Anxiety?

An iron deficiency can trigger feelings of anxiety or worsen the symptoms of anxiety. As mentioned earlier on, iron plays an important role in producing neurotransmitters like dopamine and serotonin, which influence mood and motivation.

Iron deficiency may also reduce oxygen delivery to the brain and other tissues, potentially contributing to symptoms such as:

• Anxiety
• Feeling overwhelmed more easily
• Irritability
• Poor concentration
• Low mood
• Mental fatigue

Of course, anxiety is complex and can have many causes. Low iron is rarely the only explanation (or the cause). However, if anxiety appears alongside fatigue, hair loss, dizziness or heavy periods, I’d be checking your iron!

How Do You Know If Your Iron Is Low?

The truth is that symptoms alone cannot tell you whether your iron levels are low. I know you might have read all the symptoms of iron deficiency and thought, I need to supplement with iron! But those symptoms can overlap with other nutrient deficiencies (like B12, and folate), or be caused by something else (like thyroid issues or hormonal imbalances). The only way to know if you’re deficient in iron, and how deficient you are, is through a blood test.

Iron Deficiency vs Iron Deficiency Anaemia

These two terms get mixed up a lot – they are actually slightly different. Iron deficiency occurs when your body’s iron stores become depleted and you’re now low in iron. Iron deficiency anaemia occurs later, when iron levels have fallen enough to affect haemoglobin production.

You can have low iron and experience symptoms for months or even years before becoming anaemic. This is an important thing to know because so many people are told that they’re fine simply because they are not anaemic, despite experiencing symptoms consistent with low iron.

Best Blood Test to Check Iron Levels

Most doctors are only checking one iron marker, which is usually ferritin. And while ferritin is very useful to look at, you want a full iron panel alongside a full blood count to see how deficient you are, and how it is impacting your red blood cells.

This is what’s included in a full blood count, it’s quite rare to get via the NHS in the UK. But a full panel is something that’s included in all of the private blood tests we do together in 1:1 sessions.

Serum Iron

Serum iron measures the amount of circulating iron in your bloodstream at the time of the test. Because it can fluctuate throughout the day, it’s not that useful to test on its own (I’ll see clients with a serum iron result which looks normal, but it’s literally a tiny tiny piece of the puzzle).

Ferritin

Ferritin is your stored iron. I often describe ferritin to clients as your savings account – it tells us how much iron you have available in your reserves. And this is what can dip really early before you start to see changes in the red blood cell count or haemoglobin levels. Ferritin can increase with infections and inflammation, so it’s not always a great test to do on its own. Sometimes you can get a ‘normal’ or ‘high’ ferritin result purely because you had a cold around the time of the test, and then you’ll actually miss a deficiency!

Total Iron Binding Capacity (TIBC)

TIBC looks at how much iron your body is trying to bind and transport. I describe it to clients as how ‘hungry’ your body is for iron. When TIBC is raised, it can indicate that your body is actively searching for more iron.

Transferrin

Transferrin is the protein responsible for transporting iron around the body. Transferrin is produced by the liver, so sometimes if it’s low, it can indicate an issue with liver function.

Transferrin Saturation

Transferrin saturation tells us how much of that transport protein is actually carrying iron. You can kind of think of it like a taxi full of iron, is transferrin saturation is low, there’s not much iron in your taxis. If it’s high, there’s a lot of iron in the taxi.

See how much more information we got from this full panel? Rather than testing serum iron or ferritin on their own?

Full blood count

Alongside an iron panel, I always like to see a full blood count. This allows us to assess how iron levels are affecting red blood cell production. If you have an iron deficiency or become anaemic, you start to see changes in red blood cells and haemoglobin levels. Low iron can cause red blood cells to be too small, and it’s known as microcytic anaemia.

My Doctor Says My Iron Is Normal But I Still Feel Awful

This is one of the most common conversations I have with clients. They’ll tell me they had tests done but everything has come back as normal. So why do they still feel rubbish?

They have:

• Fatigue
• Hair thinning
• Brain fog
• Dizziness
• Poor concentration

The first issue is that they haven’t had a full iron panel done alongside other nutrients or causes of their symptoms.

The second is that a lot of labs have really big reference ranges for ferritin – often ranging from 11-300+.

I’ll look at clients’ results that they had done through their doctor, and their ferritin is 11, literally on the cusp of being iron deficient by their ranges, but they won’t do anything. The client is told they’re fine, no deficiency! Now I have two issues with this: 1) Why are we waiting until someone drops one point on a blood test before we intervene? This client has all the symptoms of an iron deficiency… and 2) Why are the ranges that big! Optimal iron is around 50-100.

Why Are You Iron Deficient In The First Place?

One thing that is so commonly overlooked is why you’re deficient in the first place. Clients will casually mention they’ve always been low in iron, almost as though it’s a personality trait. When I ask whether anyone has investigated why they struggle to maintain healthy iron levels, the answer is often no.

This is a problem.

If your iron deficiency keeps returning, we need to understand why. So many of my clients will have all the symptoms of an iron deficiency, get tested, and be prescribed iron, which helps them feel better for a few months but then their levels drop again and they’re stuck in the same cycle.

Some common causes of low iron include:

• Heavy menstrual bleeding
• Low dietary iron intake
• Digestive issues affecting absorption
• Coeliac disease
• Crohn’s disease
• Ulcerative colitis
• H pylori infection
• Certain medications (like PPIs)

Unfortunately, many people are just given iron tablets without anyone investigating any underlying causes of the deficiency in the first place.

if you have heavy periods, still rule out other conditions that cause low iron!

Heavy periods are a common cause of iron deficiency. However, we shouldn’t automatically stop there and think that’s the only reason someone is deficient.

One client I worked with had heavy periods and recurrent iron deficiency. She went to have a colonoscopy done via a gastroenterologist, and he told her he didn’t want to put her through the procedure since she has heavy periods and that was likely the cause of low iron. I’d call that neglect!

When she came to me and told me she’s struggled with iron for such a long time, we investigated further by doing a stool test, we found significantly elevated calprotectin levels, which is a marker of inflammation in the gut.

I referred her back to her doctors for further investigations and she eventually received a diagnosis of Crohn’s disease. Had everyone simply accepted the heavy periods explanation, the underlying condition may have remained undiagnosed for much longer. This is why I believe in leaving no stone unturned. Low iron can be a sign of a gut issue and it needs to be investigated.

Can Foods Help Increase Iron Levels?

If you’re deficient, no. Eating iron-rich foods is important to help maintain healthy levels, but if your ferritin is below 14 you’re not going to increase it through food alone. And especially not if you’ve got heavy periods or something like IBD.

There are two forms of iron: heme and non-heme. Heme-iron comes from animal products, and non-heme comes from plant foods. Although non-heme sources look like they contain a lot of iron, it’s not absorbed as easily as heme-iron. The rate of absorption from non-heme sources is around 2-20%, whereas non-heme is 15-35%. As well, non-heme sources contain plant chemicals that naturally block iron absorption, such as tannins and phytates. You can increase iron absorption by about 2-4 times by having some vitamin C alongside a meal containing iron.

Iron Rich Foods

Sources of heme iron include:

• Red meat
• Liver
• Shellfish

These forms are generally absorbed more efficiently.

Sources of non-heme iron include:

• Lentils
• Chickpeas
• Beans
• Tofu
• Dried apricots
• Pumpkin seeds
• Dark leafy greens (best cooked)

Tips To Improve Iron Absorption

Pair iron-rich foods with vitamin C-rich foods such as:

• Peppers
• Citrus fruits
• Strawberries
• Kiwi fruit
• Orange juice

It may also be helpful to avoid drinking tea or coffee alongside iron-rich meals, as these can reduce absorption.

What Is The Best Iron Supplement?

Remember, you should only supplement iron if you know you have a deficiency. But the right supplement and dosage of iron depends on your current levels, and how well you tolerate the iron.

Most people are prescribed ferrous fumarate through their GP which can be a very high dose of iron. It helps to increase levels but it can cause some digestive issues in some people. You might notice constipation, diarrhoea or black stools while you’re taking iron supplements.

In these situations, iron bisglycinate, or a lower dose iron might be better tolerated. I do also use liquid or spray formulas of iron to help increase levels while being gentle on the stomach.

You’ll also want to retest your iron levels to see if the treatment or supplements are working. Usually we will do the first blood test, find the deficiency, put in an iron supplement for 3 months and then retest levels to see if it’s worked to increase them.

Want to look deeper into your health and low iron levels?

If you’ve been told your iron levels are normal but you’re still struggling with fatigue, hair thinning, digestive symptoms or recurring deficiencies, it may be time to dig deeper.

You can do so in my Gut Reset Programme. It’s 1:1 nutrition support that includes x2 nutritional therapy consultations and a comprehensive stool test. It’s perfect for anyone who’s struggling with symptoms but seems to keep being told everything is ‘normal’. Use this link to book your enquiry call.