Iron deficiency: causes, signs, & symptoms of low iron

Iron deficiency is one of the most common deficiencies I see as a nutritional therapist, and it’s the most prevalent nutrient deficiency worldwide. Young children, pregnant and menstruating women, vegetarians, and those with conditions such as gastritis and coeliac disease are most at risk of becoming deficient in iron — as malabsorption issues, inadequate iron intake from food, and blood loss can all deplete iron levels and lead to a deficiency over time. 

If untreated, iron deficiency can lead to a condition known as iron deficiency anemia (IDA): a risk factor for heart issues, pregnancy complications, and infections. However, the harmful effects of low iron aren’t limited to IDA, as iron deficiency without anaemia (IDWA) can also cause symptoms that significantly impair quality of life. These symptoms are often widespread and non-specific, making the diagnosis of IDWA challenging yet crucial.

Let’s take a closer look at this common yet poorly recognised mineral deficiency and discuss what you can do if you suspect you might have low iron levels. 

Anaemia and iron deficiency: what’s the difference?

Iron is an essential mineral found in each of our cells. It plays a role in the production of haemoglobin, a major protein in our blood that delivers oxygen to our organs, cells, and tissues. It also produces myoglobin, a protein that transports oxygen to our muscles. 

Iron has many other functions in the body, such as producing thyroid hormones, maintaining immune health, and supporting both brain development and brain function. Optimal iron levels are needed to synthesise hormones, neurotransmitters, new blood cells, and amino acids.

When iron levels are low, the blood can’t effectively transport oxygen to our organs, cells, and tissues. This can lead to iron deficiency anaemia — the most common type of anaemia — or iron deficiency without anaemia — an undertreated yet twice as common condition. 

Risk factors for iron deficiency

Along with malabsorption issues and inadequate iron intake from food, chronic blood loss due to heavy menstrual bleeding is a major contributor to iron deficiency among women — both with or without anaemia. This puts billions of menstruating girls, adolescents, and adults at risk of experiencing the harmful effects of low iron. Those with chronic inflammatory conditions such as endometriosis have an even greater risk.

Heavy menstrual bleeding (menorrhagia) is defined as losing more than 80 millilitres of blood during a single menstrual period, but it can also occur as a result of prolonged bleeding (i.e. bleeding for more than seven days at a time) or spotting between periods. For this reason, reproductive-age women typically require more iron from food or supplements during menstruation. 

Other causes of blood loss that increase the risk of iron insufficiency include blood donation, haemorrhoids, regular use of non-steroidal anti-inflammatory medications (NSAIDs), and inflammatory bowel disease (IBD). In fact, more than half of IBD patients — especially those with Crohn’s disease — are deficient in one or more micronutrients such as iron. 

Iron deficiency and its impact on thyroid function

IBD and coeliac disease aren’t the only autoimmune diseases associated with iron deficiency. Research suggests that low iron levels may also play a role in the development of autoimmune thyroid disease — a leading cause of hypothyroidism — by triggering inflammation in the thyroid gland. There seems to be a link between iron deficiency anaemia and subclinical hypothyroidism as well. 

Iron deficiency without anaemia, on the other hand, is shown to impact the effectiveness of hypothyroidism treatments and contributes to persistent thyroid-related symptoms such as brain fog and fatigue. However, case reports show that correcting low ferritin levels — an indication of iron deficiency without anaemia — can relieve these persistent hypothyroidism symptoms and improve quality of life.

Identifying iron deficiency

To diagnose an iron deficiency with or without anaemia, practitioners typically order a series of blood tests to measure an individual’s serum iron, haemoglobin, hematocrit, mean cellular volume (MCV), transferrin saturation, and ferritin levels. Ferritin tests are used to measure the amount of stored iron in the body, as ferritin is a more reliable marker of iron status than serum iron alone. 

Decreased ferritin levels are seen in both iron deficiency anaemia and non-anaemic iron deficiency. For example: 

• Low ferritin, serum iron, haemoglobin, hematocrit, and MCV levels indicate iron deficiency anaemia.
• Low ferritin levels and normal haemoglobin values indicate iron deficiency without anaemia. In some cases, transferrin saturation may also be low. 

Although a low ferritin level is typically defined as 30 μg/L or less, most menstruating women should have a ferritin level of between 50 and 200 μg/L — especially if they experience heavy or prolonged menstrual bleeding. Those with chronic inflammatory conditions may require even higher ferritin levels of up to 300 μg/L. 

Unfortunately, many GPs are unfamiliar with the signs and symptoms of iron deficiency in the absence of anaemia, causing patients to go undiagnosed and untreated for years. Without treatment, iron deficiency can worsen, cause other health issues, including hair loss, and lead to iron deficiency anaemia. This is what makes iron deficiency awareness and self-advocacy so crucial! 

Signs and symptoms of low iron

Iron deficiency anaemia and non-anaemic iron deficiency are not synonymous, but they’re equally as important to our health. Both can affect our physical and mental health in many ways, leading to fatigue, weakness, poor concentration, neurocognitive dysfunction, restless legs, shortness of breath, headaches, and many other symptoms. 

Some other low iron symptoms that may indicate an iron deficiency include: 

• Impairments in memory, cognition, mood, focus, and work productivity.
• Heart palpitations, exercise intolerance, and easy bruising. 
• Hair loss, brittle nails, and “spoon” nails (koilonychia).
• Pain in the muscles and joints.
• Dry skin and mouth.
• Loss of energy. 
• Severe fatigue and exhaustion during menstruation. 

If you have one or more of these iron deficiency symptoms, your GP can measure your ferritin, serum iron, and haemoglobin levels using a simple blood test. Once your test results are available, they can be shared with me before your nutritional therapy appointment.

Is an iron deficiency contributing to your symptoms?

If your iron levels are low, there are several approaches to treating an iron deficiency. Depending on your specific situation, your treatment options may include supplementation, dietary approaches, and iron infusions. 

Keep in mind that unless you know you’re deficient in iron, I don’t recommend taking an iron supplement. Excess iron can be harmful, and some people have an increased risk of iron overload (a genetic condition known as hemochromatosis). Functional nutrition testing is a crucial first step! Then, there are a few different options to consider, starting from dietary to supplemental. In terms of supplements, there are different forms of iron to consider as some are constipating for a lot of people. I can help you choose the right one.

Do you suspect you could have an iron deficiency? I can help! Iron deficiency is one of the most common nutrient deficiencies I see in my nutritional therapy practice. Book your free 20-minute inquiry call today to learn how nutritional therapy can help transform your health.