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Iron deficiency in men and women after the menopause: the gut workup | CION Cancer Clinics
Low iron in a man, or in a woman whose periods have stopped, usually needs a look inside the gut. Doctors often suggest an endoscopy of the stomach and a colonoscopy of the bowel, because slow hidden bleeding or poor absorption is the likely reason. Most causes found are not cancer. This page explains what the tests look for, what happens on the day and which signs need care today. At CION Cancer Clinics, our haematologist cares for anaemia, bleeding, clotting and inherited blood disorders, with ArogyaSri, CGHS and cashless insurance accepted.
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Medically reviewed by Dr. Basudev PokhrelConsultant Haematologist · last reviewed September 2026, next review due September 2027
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On this page
- Why would a doctor ask for a camera test for low iron?
- What are the doctors looking for?
- What happens at an endoscopy and colonoscopy?
- Does everyone need both tests, and what if they are normal?
- How do the two tests differ?
- What do families believe about these tests, and what is true?
- Common questions about the gut tests for low iron
The short answer
Why would a doctor ask for a camera test for low iron?
In men, and in women whose periods have stopped, there is no monthly blood loss to explain low iron. So doctors look for slow, hidden bleeding from the gut, or a gut that is not absorbing iron. That usually means an endoscopy of the stomach and a colonoscopy of the large bowel.
Why the gut is the first place to look
The stomach and bowel can lose a little blood every day without you seeing it. An ulcer, an inflamed stomach lining or a polyp in the bowel can all do this. Over months, that small loss empties your iron stores and your haemoglobin falls. Most of these causes are not cancer, and many are simple to treat once found.
Why doctors do not just give iron and wait
Iron tablets can raise your haemoglobin while the cause keeps bleeding quietly in the background. If that cause is a growth in the stomach or bowel, treating the numbers alone can delay finding it. Looking early is how that is avoided.
What this page cannot tell you
It cannot tell you whether you need one test, both, or neither. That depends on your age, your symptoms, your medicines, your other blood results and what has been checked before.
Low iron in a man or a woman after the menopause deserves an explanation. It is not something to simply top up for years.
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Signs of bleeding that cannot wait
If you vomit blood or something that looks like coffee grounds, pass black, sticky, tar-like stools, or pass a lot of fresh blood with dizziness, fainting or a racing heart, go to the nearest emergency department now or call 108. Do not wait for a planned endoscopy appointment. Iron tablets can darken stools too, so tell the team if you are taking them, but do not assume that is the reason.
Not sure whether this applies to you?
Ask an oncologistPossible causes
What are the doctors looking for?
Most people with low iron who have these tests are found to have a cause that is not cancer. The tests are there to find out which one it is.
Ulcers and an inflamed stomach
Painkillers such as ibuprofen and diclofenac, aspirin, and an infection called H. pylori can all damage the lining of the stomach and bleed slowly.
Often found with
- Regular painkiller use for joints or back
- A daily blood thinner
Polyps and growths
Polyps are small growths in the bowel lining. Most are harmless, but some can turn into cancer over time. Stomach and bowel cancers can also bleed slowly before they cause other symptoms.
Not absorbing iron
Coeliac disease, a reaction to gluten in wheat, damages the gut lining so iron is not taken in. A blood test is usually done, and small samples can be taken during the endoscopy.
Other causes
Fragile blood vessels in the gut lining, worm infections such as hookworm, and long-term inflammation of the bowel can all lead to low iron.
Piles can bleed, but doctors do not usually accept them as the full explanation until the rest has been checked.On the day
What happens at an endoscopy and colonoscopy?
Getting ready
For the stomach test you will be asked not to eat for some hours beforehand. For the bowel test you drink a clearing preparation the day before, which gives you loose motions. Ask your doctor what to do about your regular medicines, especially blood thinners and diabetes tablets.
The endoscopy
A thin, flexible tube with a camera goes through your mouth into your stomach and the first part of the small bowel. A throat spray or a sedative helps you relax. It is usually over quickly.
The colonoscopy
A similar tube goes in through the back passage to look at the whole large bowel. You are usually given a sedative. You may feel pressure or cramps. Both tests are often done on the same visit.
Samples and results
Small tissue samples, called a biopsy, may be taken. You feel nothing when this happens. What was seen is often explained the same day. Sample results take longer.
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Not the same for everyone
Does everyone need both tests, and what if they are normal?
Not everyone. Doctors often suggest both tests together, because a problem found in the stomach does not rule out a second one in the bowel. Your own plan is decided by the doctor who knows your history.
Who may not have both
Someone who is very frail, has serious heart or lung disease, or would not be fit for treatment of what might be found may be offered a gentler test, such as a CT scan of the bowel. Someone who had a clear colonoscopy recently may not need to repeat it. A clear cause, such as confirmed coeliac disease in a younger man, can change the plan too.
If both tests come back normal
That is reassuring, but it does not end the search if your iron keeps falling. The small bowel sits between the two areas the tests can reach. A capsule endoscopy, where you swallow a tiny camera, may be suggested. Your doctor may also look again at diet, medicines, blood in the urine and other causes.
Where a haematologist helps
When iron does not rise, the counts are very low, or other blood cells are also abnormal, a haematologist can look at the whole blood picture and arrange what comes next.
Side by side
How do the two tests differ?
Endoscopy (upper)
Colonoscopy
Looks at the food pipe, stomach and start of the small bowel
Looks at the whole large bowel and the end of the small bowel
The tube goes in through the mouth
The tube goes in through the back passage
Fasting for some hours beforehand
A bowel-clearing drink the day before
Finds ulcers, stomach inflammation, coeliac changes
Finds polyps, bowel inflammation, growths
Commonly believed
What do families believe about these tests, and what is true?
"Men do not get low iron unless they eat badly."
Diet alone rarely empties iron stores in an adult man eating a normal Indian diet. Low iron in a man is treated as a sign of blood loss or poor absorption until shown otherwise.
"The iron tablets worked, so we can skip the tests."
Tablets can raise the haemoglobin even while something is still bleeding. Feeling better does not tell you what caused the loss. Talk to your doctor before cancelling a planned test.
"Being sent for a colonoscopy means they think it is cancer."
It means the doctor wants to find the cause, and cancer is one thing they need to rule out. Most people tested have something else, such as an ulcer, inflammation or a polyp that can be removed.
"There is no blood in my stools, so it cannot be my gut."
Slow bleeding from the stomach or bowel is often too small to see. A normal-looking stool does not rule it out. That is exactly why the camera tests exist.
Questions we are asked
Common questions about the gut tests for low iron
My father has low iron. Why was he sent to a gastroenterologist?
Because in older men the most common reasons for low iron are in the gut. A gastroenterologist is the specialist who does the camera tests and treats what they find. It is a standard step, not a sign that the doctor has already decided something serious is going on.
Does this apply to women after the menopause too?
Yes. Once periods have stopped, low iron cannot be explained by monthly bleeding, so the same gut tests are usually suggested. Women who still have periods are sometimes tested too, if they have gut symptoms, a family history of bowel cancer, or iron that does not recover.
Are the tests safe?
They are very commonly done and serious problems are uncommon. Rare risks include bleeding after a sample is taken, a tear in the bowel wall, and reactions to the sedative. Your doctor will explain these before you sign the consent form, and you can ask any question you have.
Will it hurt?
Most people find it uncomfortable rather than painful. The endoscopy can make you gag briefly. The colonoscopy can cause cramps and bloating from the air used to open the bowel. A sedative helps with both. You should not drive for the rest of that day, so bring someone with you.
Should he stop his blood thinner or aspirin before the test?
Do not stop it on your own. Stopping some blood thinners suddenly can cause a stroke or a clot. Tell the doctor doing the test exactly what he takes. They will decide, with the doctor who prescribed it, whether anything should change and for how long.
Can a stool test be done instead?
A stool test for hidden blood is used in bowel screening, but it is not a substitute here. A negative result does not rule out bleeding, and it cannot see the stomach at all. In people with confirmed low iron, doctors usually prefer to look directly.
What if a polyp is found?
Most polyps can be removed during the colonoscopy itself, and you usually feel nothing when this happens. The polyp is sent to the laboratory. The result tells your doctor what type it was and when you should have your next check.
What if cancer is found?
Finding it through a blood test for low iron can mean finding it earlier. A biopsy confirms the type, and scans show how far it has spread. The plan is then made by a team of specialists. Bring a family member to that appointment and ask what each option involves.
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Dr. Basudev Pokhrel reviews blood counts, transfusion needs and blood disorders, and works with the CION tumour board on blood cancers.
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Sources
- NHS — Iron deficiency: causes and tests
- NHS — Gastroscopy
- NHS — Colonoscopy
- NICE — Clinical Knowledge Summaries: iron deficiency
- Cancer Research UK — Bowel cancer symptoms
This page is general information, not a prescription. Do not change or stop any treatment based on what you read here. If anything is worrying you, contact your own treating team — or call our helpline and we will help you reach the right specialist.
Keep reading
Related pages
Recurrent Iron Deficiency: Finding the Real CauseWhen iron keeps falling after treatmentReading a Ferritin ResultWhat your stored iron figure meansIV Iron: When Tablets Are Not EnoughWhen tablets are not absorbedBiopsy guideWhat happens to a tissue sampleIron DeficiencyThe full iron deficiency guide
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