Doctors are often hesitant to order blood tests for post menopausal women who report being more tired or having more hair loss than usual, simply because these women no longer have a period. While menstruation is the most common cause of low iron in younger women, there are multiple reasons why post-menopausal women and men over 50 years of age may be low in iron that warrant investigation. This article explains why iron levels are often low in older adults, what routine blood tests can be done to determine this, and various options available if results come back out of range.
Why Low Iron Matters
Iron is essential for producing red blood cells and supporting energy and brain function. Low iron status can cause fatigue / feeling abnormally tired, weakness, a reduced ability to exercise, and excessive hair loss. These symptoms occur before someone develops full-blown iron-deficient anemia.
Microcytic anemia
Iron deficiency can lead to microcytic anemia, characterized by red blood cells that are smaller than normal. These smaller cells are less effective at carrying oxygen, which leads to feelings of fatigue, weakness, and even shortness of breath [3].
How Common Is Low Iron?
Current data indicate that iron deficiency anemia affects approximately 1 in 7 adults over the age of 50 (U.S. data). Fatigue, brain fog, and decreased physical performance are common early signs [2][11].
Why Low Iron Happens in Adults Over Age 50
Chronic Blood Loss
The most common reason older adults develop iron deficiency is slow, chronic blood loss, which can often be from the gastrointestinal (GI) tract. Sources of GI blood loss include ulcers, diverticulosis, colon or rectal polyps, and GI cancer. As outlined in this earlier article about hemorrhoids, when having bowel movements, internal hemorrhoids can bleed microscopically without detection, resulting in low iron status. Blood loss can be subtle and occur over months or years. For this reason, once iron deficiency is detected, older men and postmenopausal women may be referred to a colorectal surgeon for a colonoscopy to rule out polyps or cancer, or for further assessment if internal hemorrhoids are suspected to be the cause[4][5].
Poor Absorption or Dietary Intake
Another reason for low iron status is dietary, which is not exclusive to older adults. Vegans are often low in dietary iron because they avoid consuming all animal products, the main source of heme, the most bioavailable form. Ovo-lacto vegetarians who consume eggs and dairy but avoid eating red meat and seafood such as oysters and clams also tend to have low iron status because these are rich sources of heme.
It is also not uncommon for older people to eat a narrower range of foods as they age, sometimes due to decreased appetite or a deterioration in their ability to chew, resulting from tooth loss.
A common symptom of celiac disease is low iron status, which is why when I have an adult male client of any age with low iron status (without any obvious reasons for it), I request a routine blood test (IgATTG) to rule that out. Since men don’t menstruate/have “periods”, asking for a requisition for this test in men with low iron makes sense. Since people with celiac disease may be asymptomatic, low iron in men of any age is often the only indication to test for it. One might assume that an older man without any symptoms would have already been tested for celiac disease at some point in his life, but sometimes a diagnosis is made only because someone requested the test. While a biopsy is needed to confirm celiac disease, an IgATTG test to screen for it makes sense in men with low iron lab results.
A Helicobacter pylori (H. pylori) infection can also result in low iron status due to decreased absorption, so requesting a test to rule out H. Pylori is reasonable if no other cause is apparent [5].
Acid-Blocker Medications and H2 Blockers / Antihistamines
Long-term use of Proton Pump Inhibitor (PPIs) medications, which are used to treat acid reflux, heartburn, ulcers, and gastroesophageal reflux disease (GERD), reduces stomach acid, resulting in decreased iron absorption [8]. Some common brand names of PPIs include Prilosec (omeprazole), Nexium (esomeprazole), Prevacid (lansoprazole), and Pantoloc (pantoprazole). In adults who have been taking PPIs long-term, a healthcare provider should monitor iron status (and bone status, which is a separate discussion!).
H2 blockers, also called H2 antihistamines, are another class of medications that reduce stomach acid by blocking histamine receptors in the stomach lining. Some common brand names include Zantac (ranitidine), which has been discontinued in Canada for a while, Pepcid and Pepcid AC (famotidine), and Tagamet (cimetidine). Monitoring iron status in older adults who frequently take these over-the-counter medications is important, but if healthcare providers don’t ask if people take them, they won’t know. I ask.
Note: While H2 blockers are most commonly used for heartburn or mild GERD, they are also used in conjunction with a “regular antihistamine”, also known as an H1 blocker or H1 anti-histamine, for the treatment of Mast Cell Activation Syndrome (MCAS). MCAS is a condition where mast cells release excessive histamine, causing symptoms including hives, flushing, stomach pain, diarrhea, headaches, and very low blood pressure. The use of both an H2 antihistamine (such as ranitidine (Zantac) along with an H1 antihistamine (such as cetirizine hydrochloride, called Reactine in Canada, and Zyrtec in the US) targets different types of histamine receptors, improving overall symptoms in MCAS. It is important to monitor iron status in those using H2 antihistamines long-term for MCAS.
Whether H2 blockers are used to reduce stomach acid or to manage the symptoms of MCAS, the reduction of stomach acid leads to decreased iron absorption, resulting in low iron status over time [8].
How Iron Is Tested
For adults over the age of 50 with symptoms of fatigue, weakness, shortness of breath, or increased hair loss, I will ask their doctor or clinic for a requisition for blood tests to assess iron status, including a Complete Blood Count (CBC), ferritin, transferrin saturation (TSAT) or serum iron, and Total Iron Binding Capacity (TIBC). If the results come back below lab normal values, then determining the underlying cause, or causes, is next.
Treatment Options for Low Iron
Determine the Cause
When blood tests come back out of range, investigations will include ruling out sources of bleeding, such as internal hemorrhoids that can cause undetectable blood loss while having a bowel movement, ulcers, or whether they may have undiagnosed celiac disease or an H. pylori infection [4][5].
Iron Supplementation
Oral iron supplements are effective for treating low iron in most older adults, and there are many different forms of iron — some with better absorption than others. There are a few newer iron formulations that cause no stomach upset or constipation, and alternate-day dosing can increase absorption [7][10]. Oral treatment will usually continue for several months until ferritin levels (ferritin being the storage form of iron) reach adequate levels, not only hemoglobin levels, which are the iron in red blood cells. In severe cases of iron-deficient anemia, intravenous (IV) iron infusions will often be recommended [9].
Practical Tips for Adults Over 50
Final Thoughts
Doctors are sometimes hesitant to requisition blood tests to screen post menopausal women for low iron status because they no longer have a period; however, blood loss from menstruation is only one cause. Even in men or in post menopausal women who are not prescribed PPIs or H2 blockers, many regularly take over-the-counter antacid tablets that, over time, can affect iron status.
A colonoscopy is recommended for adults over 50 years every ten years to check for colon polyps or cancer, but unless specifically asked, most people won’t volunteer that they have hemorrhoids, which can bleed microscopically, resulting in low iron status. Since slow GI bleeding is often “silent” in older adults [11], having members of your healthcare team ask the right questions and request blood work when necessary is essential. I ask, and if there is an area that warrants further investigation, I will request routine lab tests to be sure.
To your good health.
Joy
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References
- British Columbia Women’s Hospital and Health Centre. Iron deficiency in adults. 2019.
- Centers for Disease Control and Prevention. Data brief: Iron deficiency in U.S. adults. 2018. Available at: https://www.cdc.gov/nchs/products/databriefs/db519.htm. Accessed November 7, 2025.
- Merck Manual Professional Edition. (2024). Overview of microcytic anemia. Merck & Co., Inc. https://www.merckmanuals.com/professional/hematology-and-oncology/anemias-caused-by-deficient-erythropoiesis/overview-of-microcytic-anemia
- American Gastroenterological Association. Gastrointestinal evaluation of iron deficiency anemia guidelines. 2023. Available at: https://gastro.org/clinical-guidance/gastrointestinal-evaluation-of-iron-deficiency-anemia/. Accessed November 7, 2025.
- British Society of Gastroenterology. Iron deficiency in adults: guideline. Gut. 2021;70:203–228. Available at: https://www.bsg.org.uk/resource/iron-deficiency-in-adults.html. Accessed November 7, 2025.
- Medscape. Iron deficiency anemia guidelines. 2023. Available at: https://emedicine.medscape.com/article/202333-guidelines. Accessed November 7, 2025.
- Weiss G, Goodnough LT. How I treat anemia in older adults. Blood. 2024;143(3):205–215. Available at: https://ashpublications.org/blood/article/143/3/205/494702/. Accessed November 7, 2025.
- Ganz T, Nemeth E. Inflammation and iron metabolism in older adults. PMC. 2014;5:210–220. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4157323/. Accessed November 7, 2025.
- Macdougall IC, et al. IV iron therapy in older adults. PMC. 2006;12:115–124. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10808247/. Accessed November 7, 2025.
- Ashcroft DM, et al. Oral iron in older adults. Blood. 2024;143(3):225–234. Available at: https://www.cghjournal.org/article/S1542-3565(24)00410-5/fulltext. Accessed November 7, 2025.
- Penninx BW, et al. Iron status and outcomes in older adults. PMC. 2014;11:145–156. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4325864/. Accessed November 7, 2025.
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