Why So Many Post Menopausal Women and Older Men Have Low Iron

Over the years I have noticed more and more post menopausal women and older men with low iron stores and iron-deficient anemia and wondered why. Women’s iron needs are less after menopause since they no longer have monthly loss of blood from menstruation, so what contributes to this? And why are men low in iron?

It should be noted that in this article, I am only discussing low iron stores and iron-deficient anemia and not anemia of other types, such as accompanies low vitamin B12 status or a problem with intrinsic factor that helps absorb it; both of which are common as people age, nor they type that is the result of low folate intake.  This is a different type of anemia, called macrocytic anemia, where the blood cells are fewer, but larger than normal (macro means larger).

Microcytic anemia is where there are fewer red blood cells and they are smaller than normal (micro means small) and this is caused by conditions that keep the body from making enough hemoglobin, the oxygen carrying part of the blood. Low levels of hemoglobin in red blood cells results in the red blood cells appearing paler in colour and this is called hypochromic (hypo means low, chromic means colour). Iron deficient anemia is the most common type of hypochromic microcytic anemia.

Low iron stores or iron deficient anemia

May be caused by;

  1. inadequate dietary intake such as is common in those who are vegetarian (eat no meat from animals) or vegan (eat no animal products, including no eggs or cheese).
  2. decreased absorption which is common in conditions such as Celiac disease or in those that have h. pylori; a type of bacteria that causes stomach ulcers (or may be without symptoms at all
  3. chronic blood loss, such as is common in women with heavy menstrual periods or in those with inflammatory gastrointestinal (GI) diseases and experience internal bleeding, such as those Crohn’s Disease or Ulcerative Colitis.
  4. pregnancy due to increased blood needs of the fetus.

Post-menopausal women are past the age where they can either be pregnant or have periods, so low iron stores or iron-deficient anemia in older women are for reasons similar to older men; either due to decreased iron absorption or chronic blood loss.

In older adults with low iron stores or iron deficient anemia, the first thing I rule out is Celiac Disease because it is as simple as a routine blood test, and a fair number of people with the disease (immune reaction to gluten) have no symptoms whatsoever. The second thing I rule out is any history of- or symptoms of stomach ulcers, which is caused by the helibacter pylori (h. pylori) bacteria. This bacteria takes up iron and can contribute to reduced iron status in its host. Ruling this out can be done by a breath test looking for urea given off by the bacteria.

Assuming an older adult tests negative for both Celiac disease and h. pylori and does not have any chronic disease that may be causing the anemia ⁠— then what can be contributing to them having lower than normal iron stores or iron deficiency?

Iron deficient anemia (IDA) occurs in ~2%-5% of adult men and postmenopausal women; with blood loss from chronic blood loss from gastrointestinal bleeding being the most common cause [1,2] and malabsorption being the second most common [2,3].  Goddard et al [2] found that 5-10% of of iron deficient anemia is due to malabsorption mainly from Celiac disease, but since there was very little research assessing iron deficient anemia in post menopausal women, a 2015 study from Pakistan sought to do that [4]. 

Chronic blood loss is not only caused by inflammatory bowel diseases such as Crohn’s and Colitis, but with long term used of aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs) such as Advil® (ibuprofen) and Naproxen®. For years, doctors often recommend that older adults take a “baby aspirin” (low dose ASA, 81 mg) to lower their risk of heart disease, but long term use of even the small dose has been associated with GI bleeding. A study published in October 2018 in the New England Journal of Medicine found that for every 1,000 people taking low dose ASA, 11 avoided a serious cardiovascular event (heart attack, stroke) but 9 experienced GI bleeding serious enough to result in hospitalization or even death [5]. As a result, physicians are re-thinking the previous recommendation for people without a previous heart attack or stroke to take low dose aspirin [6]. Older adults who have been taking NSAIDs for pain or a low dose ASA to protect against heart attack and stroke may have low iron stores or even iron-deficiency as a result.

A major contributor to iron deficiency caused by malabsorption other than Celiac Disease in older adults is the use of Histamine-2 Receptor Antagonists (H2 antihistamines) such as Ranitidine which is the active ingredient in over-the-counter stomach acid reducer, Zantac®, as well as the commonly prescribed Proton Pump Inhibitors (PPIs). Gastric acid inhibitor use of either H2 antihistamines or PPIs for ≥2 years is known to be associated with an increased risk of iron deficiency [7], so those with Gastroesophageal Reflux (GERD), chronic heartburn or indigestion or Histamine Intolerance taking these medications are at risk.  

Reduced iron status in older adults taking NSAIDs, including low dose aspirin or gastic acid reducers such as Zantac® or PPIs is quite common, so finding ways to decrease dependence on NSAIDS for pain reduction strategies by exploring dietary strategies including an Anti-Inflammatory Diet can be very helpful.

In addition, weight loss especially reduction of weight carried around the abdomen can result in a reduction of- and often a discontinuation of the need for gastric acid inhibitors.

Finally, a major challenge in determining the cause of lower iron stores or iron deficient anemia in older adults is that chronic diseases such as diabetes and chronic kidney disease can cause the anemia of chronic disease (ACD) also called anemia of inflammation, which is very similar to iron deficient anemia (IDA). It is important to distinguish the two.  The 2015 study from Pakistan had a rather simple, but ingenious way of doing so. Subjects who were deficient were given iron supplementation and most improved indicating that there was no malabsorption, but low intake. However if there was no change in serum iron when serum iron was re-tested, these individuals were concluded to be iron deficient due to malabsorption.  In those with malabsorption due to Celiac disease for example or the use of gastic acid inhibitors that can’t be reduced, recommendation is for intravenous iron administration, as oral iron administration is not effective.

More Info?

If you are an older adult and have lower than optimal iron stores or have been diagnosed with iron deficiency, working with your doctor I can help rule out whether it may be a result of asymptomatic Celiac Disease, over the counter or prescribed medications that you’ve been taking, inadequate dietary intake or malabsorption that has contributed to the problem.

You can find out more about the packages and hourly consultations I offer by clicking here and if you would like additional information, please send me a note using the Contact Me form above and I will reply as soon as I can.

To your good health!


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  1. Guralnik JM, Eisenstaedt RS, Ferrucci L, Klein HG, Woodman RC. Prevalence of anemia in persons 65 years and older in the United States: evidence for a high rate of unexplained anemia. Blood. 2004;104:2263–2268
  2. Goddard AF, James MW, McIntyre AS, Scott BB. Guidelines for the management of iron deficiency anaemia. Gut. 2011;60:1309–1316
  3. Amy Z, Kaneshiro M, Kaunitz JD. Evaluation and
    treatment of iron deficiency anemia: a gastroenterological
    perspective. Dig Dis Sci. 2010;55(3):548-559.
  4. Qamar K, Saboor M, Qudsia F, Khosa SM, Moinuddin, Usman M. Malabsorption of iron as a cause of iron deficiency anemia in postmenopausal women. Pak J Med Sci. 2015;31(2):304–308.
  5. The ASCEND Study Collaborative Group. Effects of aspirin for primary prevention in persons with diabetes mellitus. N Engl J Med 2018; 379:1529-1539
  6. Harvard Health Publishing, Rethinking low-dose aspirin, https://www.health.harvard.edu/heart-health/rethinking-low-dose-aspirin
  7. Lam JR, Schneider JL, Quesenberry CP, Proton Pump Inhibitor and Histamine-2 Receptor Antagonist Use and Iron Deficiency. 2017 Mar;152(4):821-829.


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