Iron Deficiency in Men: Why GI Doctors Should Never Ignore It

Iron deficiency in a man is never normal. While it may seem common in women of childbearing age, in men it should always raise suspicion for a more serious underlying cause. In fact, it’s often one of the earliest red flags for slow gastrointestinal bleeding — and in some cases, even hidden GI cancer.

As a hematologist, I recently encountered a patient who illustrates this risk. I diagnosed iron deficiency anemia in a man and referred him to gastroenterology. Unfortunately, the gastroenterologist saw him after IV iron therapy when the blood counts were normal again. Therefore, the gastroenterologist dismissed the referral without further evaluation.

This delay could mean the difference between catching an early GI cancer and discovering it too late.

For gastroenterologists who are on the front lines of identifying the source of blood loss, collaboration with hematology can make a critical difference.

Here are three key points to keep in mind.

1. Iron Deficiency in a Man Is Rare — and Usually Serious

In premenopausal women, iron deficiency is often explained by menstrual blood loss. But in a man, it is unusual. Possible causes include:

• Nutritional deficiency — uncommon in most men with balanced diets.

• Malabsorption — such as from Helicobacter pylori infection or prior gastric bypass surgery.

• Occult GI bleeding — the most concerning possibility, requiring urgent evaluation.

Until proven otherwise, assume the cause is bleeding.

2. Scoping Matters

Once iron deficiency is confirmed, the question becomes: Where is the blood loss coming from?

• Colonoscopy can identify lower GI bleeding sources.

• Upper endoscopy may reveal ulcers, esophagitis, or infection with H. pylori.

• Video capsule or enteroscopy can detect bleeding in the small intestine.

The workup is essential — because without it, we risk missing life-threatening diagnoses.

3. Collaboration Saves Lives

If there’s ever uncertainty about the diagnosis, the simplest step is often the most powerful: pick up the phone. A quick conversation between hematology and gastroenterology can prevent unnecessary delays, duplicate workups, and, most importantly, missed cancers.

Collaboration ensures patients get timely, accurate care.

A Smarter Way Forward

Busy practices don’t always have the bandwidth to sort out complex hematology questions. That’s why I created a simple solution: a subscription model where providers can have a hematologist on call.

For less than the cost of a screening colonoscopy, you can have direct access to expert hematology input. No endless chart review, no second-guessing — just clear answers in minutes, so you can move on with your daily practice.

Final Thoughts

Iron deficiency anemia in a man is a diagnosis that should never be dismissed. It almost always means there is an underlying cause that requires investigation, and at the top of the list is gastrointestinal bleeding.

By combining thoughtful endoscopic evaluation with quick hematology collaboration, we can save time, prevent errors, and — most importantly — save lives.

If you’re a provider who wants fast, reliable hematology support in your practice, I’d love to connect with you.