Updated: Oct 9, 2018
Iron imbalance (overload or deficiency) is one of the most ubiquitous health conditions in the world. It’s estimated that almost half of the world’s population has a health issue that stems from, or is worsened by iron imbalance. Detection and treatment of iron imbalance is lacking in precision, and merely taking extra supplemental iron, isn’t the answer to iron deficiency. Given that iron imbalance is so widespread, and it’s consequences are potentially fatal, examining iron status is a priority for optimal health.
Iron-deficiency Anemia, the most severe stage of iron deficiency, affects an estimated 2 billion people worldwide. The problem is vastly greater when considering those with only mild iron deficiency, and those who go undetected completely.
Many specific populations carry a greater propensity for iron deficiency or anemia:
Women experience greater risk due to menstruation whereas men tend towards iron overload
Children are at risk they have an increased demand due to rapid growth
Elderly people have an increased risk because of low stomach acid, gastritis, and increased prevalence of H. pylori infection, and other chronic infections
Vegetarians and especially vegans are at high risk because their diets do not contain heme iron, the form of iron found in animal products.
Endurance athletes suffer increased microscopic bleeding from the GI tract or increased fragility and haemolysis of red blood cells.
Women with dysmenorrhea and heavy periods
People with gastrointestinal disorders (SIBO, IBD celiac etc)
Patients using long-term Proton Pump Inhibitors (acid blockers)
African American and Hispanic women possibly because of different hemoglobin needs
Iron Deficiency Symptoms
Iron deficiency can, and commonly does occur without anemia. Many people with iron deficiency may not even know they suffer from it, given that the symptoms can range from mild and generalised symptoms like fatigue, to severe symptoms like heart palpitations or infections, and iron deficiency can even be fatal.
A lack of iron decreases oxygen availability throughout the body, and decreased myoglobin (iron and oxygen binding protein) levels in muscles and this further limits oxygen availability. Because oxygen availability is central to our function, iron deficiency can cause systemic, non-specific symptoms.
Rapid breathing on exertion
Poor cognitive function
Reduced exercise tolerance
Inability to maintain body stable temperature
Sores at corners of mouth
Pica (eating of non-food substances such as dirt or paint)
Hypothyroidism because iron deficiency reduces T4 to T3 conversion, reduces thyroid synthesis and reduces thyroid peroxidase activity
Importance Of Iron
Iron is an essential nutrient. Humans depend on iron to produce red blood cells, and to make hemoglobin (transports oxygen) and myoglobin (stores oxygen in muscles), thus it’s essential for energy and function. Iron helps convert blood sugar into energy, and our physical and mental growth, immune system, enzyme production all rely on iron.
Despite the importance or iron, we only require small amounts per day, and about 90% of the iron from our diet is excreted. Iron cannot actually be absorbed directly, it must be oxidised, and then exposed to the acidity of our stomach, in order to be converted into ferrous iron which is then absorbed.
‘Despite the fact that iron is the second most abundant metal in the earth's crust, iron deficiency is the world's most common cause of anemia. When it comes to life, iron is more precious than gold.’
The Main Causes Of Iron Deficiency
There are two major causes of iron deficiency: increased demand, and decreased absorption. Increased demand occurs in pregnancy, uterine fibroids, gastrointestinal bleeding, events of heavy blood loss (accidents, surgeries, blood donations, heavy menstruation), certain medications and supplements, alcohol abuse, heavy metal poisoning.
Decreased iron uptake occurs with low stomach acid, plant based diets (vegetarian/vegans), high intake of foods that inhibit iron (see below), medications like proton pump inhibitors (antacids), celiac, Crohn’s or autoimmune disease, hormone imbalance, low or lack of intrinsic factor.
Stages of Iron deficiency:
Iron stores (ferritin) are low between 10-15ng/ml. At this level iron stores are not completely exhausted, and there may not be any obvious symptoms of iron deficiency.
Iron stores are exhausted and ferritin drops below 10ng/mL. Symptoms are often prevalent in this stage, and increase in severity as deficiency increases.
Iron deficiency anemia: there is no iron in bone marrow stores, symptoms exacerbated and red blood cell production and hemoglobin drop.
Anemia is one of the world’s biggest health problems, and often poorly diagnosed and treated as merely a need for more iron. Iron deficiency is the most prevalent cause of anemia, but it’s crucial to recognise low iron isn’t the only form of anemia. Other forms of anemia include folate or B12 deficiency anaemia, anamia of chronic disease so it's important to check which type is present. The most common causes of anemia in the industrial world are nutritional deficiency (iron, B12, or folate), increased demand, blood loss, hypothyroidism, and disease.
‘If you asked the average doctor or patient what causes anemia, the likely answer is not enough iron, and if you ask them what the treatment is, the answer will likely be iron supplements.’
- Chris Kresser, ADAPT
Signs of anemia are similar to iron deficiency symptoms, with the addition of the following symptoms like twitching / flinching, pale skin, tongue, palms, fingernails, hyposalivation, thrush, headaches, chest pain, anxiety and panic attacks
Patients with iron deficiency are routinely missed because many clinicians don’t test iron, but rather look at a complete blood count, red blood cells, or hemoglobin. If it’s found that a patient has low red blood cells and hemoglobin, it’s often assumed it’s iron deficiency, without even examining specific iron markers. This is a erroneous assumption given that many other factors can cause Anemia.
The most commonly assessed iron marker is serum iron, however it is the least accurate as many common drugs, hormones, stress, or sleep deprivation can alter this marker. Ferritin, transferrin saturation, unsaturated iron binding capacity (UIBC), are the most sensitive markers for detecting iron deficiency. Ferritin is an acute phase reactant, meaning that it’s value increases during an inflammatory response. Therefore high ferritin is not always high iron, and could be falsely high due to an inflammatory condition (disease, infection etc) leading to incorrect diagnosis. In cases when ferritin is high, it’s helpful to check soluble transferrin receptor which helps clarify iron deficiency, or overload, in patients with inflammation.
It’s also helpful to get your practitioner to assess red blood cell distribution width (RDW), which if elevated can help diagnose nutritional deficiency (iron, folate, B12) and distinguish between differing types of anemia such as iron deficiency anemia, or B12 deficiency anemia.
Another important note about conventional testing is that the laboratory reference ranges can be too broad for a variety of reasons. A narrower reference range, and careful attention to the specific patients case can help better detect iron deficiency before it progresses. For example the standard ferritin reference range for pre-menopausal women is 15-150ng/ml, but the tighter functional range of 30-100 ng/ml helps better catch low iron stores.
A Functional Medicine Approach To Iron Deficiency
The functional medicine approach always involves addressing the underlying cause. In the case of iron deficiency or iron deficiency anemia the common underlying causes include, gastrointestinal disorders, metal toxicity (lead), hypothyroidism, inflammation and inflammatory conditions, nutrient deficiency. Unless these underlying causes are addresses, iron deficiency will remain and possibly worsen.
Pathogens sequester iron for their personal gain, and so when parasites, pathogenic bacteria or yeast are present, iron status will often be low. As such it’s important to test for optimal gut health and screen for parasites, small intestinal bacterial overgrowth etc, rather than just taking more iron, and feeding the bad guys! During infection, the body shunts iron into the ferritin storage form so that pathogens can’t use it, which also renders it unavailable to your body. Hence those suffering from chronic infections, often experience low iron status.
Addressing Iron deficiency:
Investigate, and treat underlying causes
Focus on foods highest in heme iron
Reduce substances that decrease iron absorption
Increase substances that assist iron uptake
Focus On Foods Highest In Iron
There are two forms of iron, heme iron which is found exclusively in animal products, and non heme iron which is found in plants, dairy products, and in some meats. In terms of absorption, Heme iron is superior and is absorbed twice as well as non heme iron. Additionally non heme iron absorption is altered by a variety of commonly consumed substances.
‘The U.S. Food and Nutrition Board has estimated that the bio-availability of iron from a vegetarian diet is about half what it is from an omnivorous diet, so not only is the amount of iron that vegetarians and vegans consume lower, the bio-availability of that iron is lower. The absorption of plant-based forms of iron are inhibited by other commonly consumed substances such as coffee, tea, dairy products, supplemental fiber, and supplemental calcium. This explains why vegetarians and vegans have lower iron stores than omnivores and why vegetarian diets have been shown to reduce non-heme iron absorption by 70 percent and total iron absorption by 85 percent.’ - Chris Kresser, ADAPT
Foods highest in heme iron include clams, chicken liver, oysters, octopus, beef liver, venison, muscle, beef cheek, bison etc. Foods highest in non-heme iron: spices, pumpkin seeds, sesame seeds, sun dried tomatoes, natto, baked potatoes, sunflower seeds, hazel