What causes iron deficiency?
When we find that someone has iron deficiency, first, we determine what caused the deficiency. A nutrient deficiency is generally a result of insufficient intake or absorption, excess loss, or a combination of these factors.
Who is at risk of iron deficiency?
Iron deficiency (and anemia) may result from blood loss (for e.g., due to menstruation, hemorrhage, cancer, phlebotomy, blood loss from the gastrointestinal tract, such as in colon cancer or inflammatory bowel disease), reduced iron absorption (e.g., in gastrointestinal conditions such as Celiac disease, inflammatory bowel disease, SIBO or gastric bypass surgery), medications such as proton pump inhibitors and H2 blockers used for acid reflux (by reducing iron absorption), blood thinners (by increasing the risk of bleeding), a diet lower in bioavailable iron (such as vegetarian or vegan diets), or some of the rarer causes.
Once iron deficiency is identified, it is important to search for the root cause. For instance, for a man with iron deficiency, or a post-menopausal woman with iron deficiency, or for anyone >50 years old or at higher risk of gastrointestinal cancers, a physician will want to rule out gastrointestinal bleeding and cancer as a cause.
Why are women prone to iron deficiency?
Women of reproductive age, who are menstruating, are susceptible to iron deficiency due to regular blood loss. Women with heavy periods, uterine fibroids, pregnancy or blood loss during delivery, may be more likely to have iron deficiency and anemia.
What lab studies are used to evaluate iron?
Labs to assess for iron deficiency include serum ferritin and iron panel. The latter consists of serum iron, total iron binding capacity (TIBC; transferrin), and transferrin saturation (iron in serum/TIBC). Ferritin is the most useful test for iron deficiency. If it’s low, this is diagnostic for iron deficiency. Additionally, TIBC may be elevated in iron deficiency, while transferrin saturation is typically low. Goal ferritin is 40-200 ng/mL or mcg/L though lab specific ranges may be somewhat different (e.g., 16-154 ng/mL). Note that lab reference ranges may not necessarily be optimal ranges, especially when it comes to the lower end of the range. After repletion, target ferritin is 50 ng/mL, but the target may be higher in some instances. For restless legs, it is >75 ng/mL and in hair loss >70-80 ng/mL Many functional medicine physicians aim for ferritin in the range of 50-100 especially in conditions such as Hashimoto’s thyroiditis and hair loss.
In our practice, part of our comprehensive lab assessment includes a nutrient evaluation, which includes iron panel and ferritin. Given how common iron deficiency is, as well as other nutrient deficiencies, such as vitamin B12 and vitamin D deficiencies, it is important to screen for nutrient deficiencies, and if discovered, work them up and correct them. This is particularly the case for individuals who may have risk factors for nutrient deficiencies. These include women with heavy periods being at risk for iron deficiency, individuals with poor nutrient absorption due to a gastrointestinal condition impairing absorption or increasing blood loss, or significant dietary restrictions or intolerances.
What are the stages and symptoms of iron deficiency?
In the first stage of iron deficiency, iron can be depleted, but we may not see anemia yet (anemia being low red blood cell and Hemoglobin levels, which carry oxygen to the tissues). If blood work is checked, and iron panel and ferritin are not specifically ordered by our doctor or provider, iron deficiency may be missed. Many individuals have iron deficiency without anemia (i.e., if anemia is not present yet).
Iron deficiency with anemia, or severe iron deficiency without anemia can cause fatigue, reduced exercise tolerance, dizziness, weakness, headache, shortness of breath, hair loss, brittle nails, pale skin and pale conjunctiva, restless leg syndrome, difficulty concentrating, cognitive symptoms and difficulty with sleep. Furthermore, iron deficiency has been associated with fibromyalgia and ongoing symptoms for individuals with hypothyroidism (underactive thyroid gland, most commonly due to Hashimoto’s thyroditis). Iron deficiency can also cause craving for non-food substances such as clay, dirt, paper products, or ice, known as pica.
When we miss iron deficiency, we miss an opportunity to significantly alleviate potential symptoms, reduce complications, as well as address its cause.
How do we correct iron deficiency?
In our practice, our integrative health advisor supports patients in boosting iron intake via diet, however as this is not sufficient as a standalone intervention, we use supplemental support to reach target iron levels. Iron supplementation is especially used in cases of severe iron deficiency, presence of symptoms, and/or presence of anemia. We monitor ferritin and iron panel (and complete blood count in the presence of anemia) typically 2-3 months after iron supplement initiation to assess the response to treatment and adjust dosing, if needed. In more severe cases, blood work may be followed up sooner.
While we usually give supplements orally, IV iron is used in certain cases. For instance, if iron absorption is significantly compromised, in conditions such as inflammatory bowel disease, in chronic kidney disease, and in second and third trimester of pregnancy (to ensure that the fetus is getting the iron).
There are many different formulations that are generally considered to be equally effective. Iron supplements are known for causing gastrointestinal symptoms such as constipation (in some cases diarrhea), nausea, vomiting, or bloating. As a result, we must balance delivering adequate dose but also be mindful of potential symptoms that may affect patient tolerance and adherence.
Dosing is typically daily or every other day. Formulations typically range from 15mg to 65mg elemental iron (although lower and higher doses can be found). Taking iron with vitamin C or vitamin C rich food can help with absorption. Calcium can inhibit iron absorption, so these should be avoided together. It’s important to work with a healthcare provided who can diagnose iron deficiency, appropriately treat the deficiency, identify and address root cause(s), and monitor therapy.
To learn more about working with our practice, call us at 646.627.8000 or reach out to Bridget Shaffo at bridget@drbojana.com.