Can a Hernia Cause Iron Deficiency?

Large hiatal hernias can and do cause iron deficiency anemia, and the connection is better documented than most people realize. The main culprit is a type of erosion called a Cameron lesion, which forms where the stomach slides against the diaphragm, causing slow, invisible blood loss that drains iron stores over months or years. Studies estimate that somewhere between five and nine percent of patients investigated for unexplained iron deficiency anemia turn out to have a large hiatal hernia as the underlying cause, yet the diagnosis is frequently missed on initial workup.

How a Hiatal Hernia Causes Iron Loss

A hiatal hernia forms when part of the stomach pushes upward through the opening in the diaphragm. Small hiatal hernias are extremely common and usually harmless. The trouble starts when the hernia is large enough that a substantial portion of the stomach sits above the diaphragm. In that position, the gastric mucosal folds at the “neck” of the hernia get squeezed and rubbed every time you breathe. The diaphragm contracts and relaxes roughly 20,000 times a day, and that persistent friction damages the mucosa, producing shallow erosions or linear ulcers on the crests of the folds.

These erosions are called Cameron lesions, after the gastroenterologist who first described them systematically. They tend to be small and superficial, which is precisely why they are so problematic: they bleed slowly rather than dramatically. You do not vomit blood or pass visibly dark stool. Instead, tiny amounts of blood seep into the GI tract day after day. Over time, the cumulative loss depletes your body’s iron reserves, and iron deficiency anemia develops.

The exact mechanism behind Cameron lesions is not fully settled, but researchers point to three overlapping factors. Mechanical trauma from the diaphragm’s rhythmic contractions is considered the leading cause. Acid injury from gastric secretions bathing the exposed folds adds a second layer of damage. And localized ischemia, where the diaphragm compresses blood vessels in the herniated portion of the stomach, may restrict blood flow enough to weaken the mucosal lining further.¹ Concurrent Helicobacter pylori infection has also been implicated as a contributing factor in some patients.²

The bleeding is almost always “occult,” meaning hidden. Standard stool tests for visible blood can miss it. A prospective study of patients with iron deficiency anemia found that a large hiatal hernia was the likely cause in about nine percent of cases, with median hemoglobin levels around 7.9 g/dL at diagnosis, well into severe anemia territory.³ An older but larger series of 450 hiatal hernia patients found that roughly one in five had anemia, and it was consistently the iron-deficiency type.⁴

Why This Diagnosis Gets Missed So Often

One of the most frustrating aspects of hernia-related iron deficiency is how frequently doctors overlook it, even when they are actively looking for a cause. Cameron lesions sit at the diaphragmatic impression, a spot that can be difficult to visualize during a standard upper endoscopy. The lesions are shallow, sometimes only a few millimeters wide, and they can be hidden in folds of mucosa that bunch up around the hernia neck. A systematic review found that as many as 69 percent of patients had undergone one or more previous upper endoscopies before a Cameron lesion was finally identified as the source of their anemia.⁵

This means patients often go through repeated rounds of testing, including colonoscopies, capsule endoscopies, and CT scans, all coming back normal, while the real culprit sits quietly in the hernia. If you have a known large hiatal hernia and unexplained iron deficiency, it is worth specifically asking your gastroenterologist to look carefully at the hernia neck during endoscopy. The lesions are not hard to treat once found; they are just hard to see if no one is looking for them.⁶

In elderly patients especially, finding a large hiatal hernia on upper endoscopy along with a negative colonoscopy can complete the diagnostic workup and spare the patient further invasive testing.⁷ That said, doctors rightly want to rule out more dangerous causes of GI blood loss, such as colorectal cancer, before attributing anemia to a hernia. The two conditions are not mutually exclusive.

When Iron Supplements Are Not Enough

Because the anemia develops from chronic blood loss, the first line of treatment is straightforward: replace the lost iron and reduce stomach acid with a proton pump inhibitor (PPI) to help the erosions heal. For many patients, this combination works. One study of patients with large hernias and linear gastric erosions found that iron therapy corrected the anemia in all participants.⁸

The catch is that medical therapy often only works for as long as you keep taking it. The hernia is still there, the diaphragm is still moving, and the erosions tend to recur once treatment stops. Some patients develop what clinicians call “iron-refractory” anemia: their body simply cannot absorb or retain enough iron orally to keep pace with the ongoing losses. In those cases, intravenous iron infusions and even blood transfusions become necessary to manage symptoms.⁹ A child with iron-refractory iron deficiency anemia linked to a hiatal hernia saw no improvement with iron supplementation until the hernia itself was surgically repaired.¹⁰

The pattern is telling: in a multicenter study, prior iron therapy had failed in about 78 percent of patients over an average of nearly six months before they were referred for surgical evaluation.¹¹ If you have been taking iron supplements for months without your levels improving, a large hiatal hernia could be the reason.

What Surgery Can Do

Hernia repair addresses the root of the problem rather than managing its downstream effects. By pulling the stomach back below the diaphragm and tightening the hiatal opening, surgery removes the mechanical conditions that produce Cameron lesions in the first place. The results are often striking. In the multicenter study mentioned above, anemia resolved in about 93 percent of patients within 12 months of surgical repair, with nearly 89 percent reaching normal hemoglobin by three months. Average hemoglobin rose by about 3.2 g/dL, and ferritin levels climbed from around 19 to roughly 95 ng/mL. More than 80 percent of patients were able to stop iron supplements entirely.¹¹

The durability of surgical correction is a key advantage over long-term medical management. Research has found that while medication improves hemoglobin, the addition of surgery normalizes it in a way that lasts, allows patients to stop medications, and improves quality of life.¹² Some researchers argue that patients with anemia from massive hernias should be offered surgical repair even when they have no other symptoms like heartburn or difficulty swallowing, because the anemia alone is reason enough.¹³

Modern hernia repair is typically done laparoscopically, meaning small incisions and a shorter recovery than open surgery. For elderly patients or those with other health conditions, the risk-benefit calculation of surgery becomes more nuanced. But the data consistently show that when surgery is performed, the anemia improves in the vast majority of cases.

Not Just Hiatal Hernias

When people ask whether a hernia can cause iron deficiency, they usually mean hiatal hernias, and that is where the strongest evidence sits. But there is at least one other scenario worth mentioning. Ventral or incisional hernias that have been repaired with surgical mesh can, in rare cases, cause GI bleeding if the mesh erodes into the bowel wall. One case involved a 76-year-old woman who experienced intermittent, transfusion-dependent GI bleeding for two years. Multiple endoscopies could not find the source. Finally, a video capsule endoscopy revealed that her hernia repair mesh had migrated into the small bowel wall and was causing the bleeding.¹⁴

Mesh erosion is a rare complication, and it would be unusual for a standard inguinal or umbilical hernia without mesh involvement to cause iron deficiency. The common groin hernia, for instance, does not normally involve the stomach lining or cause blood loss. The concern is specific to hernias that either involve gastric mucosa directly (like hiatal hernias) or involve surgical materials that can migrate into the GI tract over time.

Who Should Be Thinking About This

Hernia-related iron deficiency tends to follow a recognizable profile. Most patients are older adults, often in their sixties and beyond, when hiatal hernias have had decades to enlarge. The hernias involved are almost always large, with a significant portion of the stomach sitting above the diaphragm. Cameron lesions were found in about a third of the patients whose anemia was attributed to a large hiatal hernia in one prospective study.³ The remaining two-thirds may still be losing blood from diffuse mucosal congestion without discrete erosions that endoscopy can easily identify.

Women are affected more often in clinical series, partly because women are more prone to iron deficiency in general and partly because hiatal hernias are more common in women. But men with large hiatal hernias are not immune. Anyone with a known large hiatal hernia who develops unexplained fatigue, pallor, shortness of breath on exertion, or laboratory findings of low ferritin should have the hernia considered as a potential cause rather than treated as an incidental finding on imaging.

It is also worth flagging that medications can worsen the picture. Nonsteroidal anti-inflammatory drugs and blood thinners do not cause Cameron lesions, but they can intensify bleeding from lesions that already exist. If you take aspirin or similar medications daily and have a large hiatal hernia, the combination may accelerate iron depletion beyond what it would be from the hernia alone.

Rare Complications of Cameron Lesions

While most Cameron lesions cause only slow, occult bleeding, they occasionally lead to more dramatic problems. Acute upper GI bleeding, where the patient vomits blood or passes large amounts of dark stool, has been reported. These episodes can be alarming and sometimes require emergency endoscopy or transfusion. Larger or deeper Cameron ulcers (as opposed to the more typical shallow erosions) can be particularly difficult to manage because the mechanical forces that created them do not stop just because acid-suppressing medication is started.¹⁵

Other rare complications of massive hiatal hernias include esophageal strictures, Barrett’s esophagus, and hernia incarceration or perforation.¹⁶ These are separate problems from the iron deficiency, but they underscore that large hiatal hernias are not always the benign findings they are sometimes portrayed as. When anemia is present alongside a large hernia, it is a signal that the hernia is causing real physiological consequences.

Confounders and Coexisting Causes

Iron deficiency is common, and so are hiatal hernias. The two sometimes appear together without one causing the other. One study examining endoscopic predictors of iron deficiency in patients with H. pylori gastritis found no statistically significant difference in the prevalence of hiatal hernias between iron-deficient and iron-replete patients.¹⁷ That does not contradict the Cameron lesion mechanism; it simply reminds us that having a hiatal hernia does not automatically mean it is the cause of your low iron. Small hiatal hernias, in particular, rarely produce Cameron lesions or significant bleeding.

Other common causes of iron deficiency, including heavy menstrual periods, celiac disease, poor dietary intake, and colorectal polyps or cancer, should always be investigated before or alongside the hernia diagnosis. The responsible approach is to treat the hiatal hernia as one piece of the puzzle rather than the automatic explanation for every case of low iron that happens to coincide with a hernia on imaging. The hernia earns its status as “the cause” when it is large, when Cameron lesions or mucosal congestion are visible on endoscopy, and when other causes have been reasonably excluded.¹⁸

When Iron Deficiency Is the Only Symptom

Many patients with hernia-related iron deficiency have no classic hernia symptoms at all. They do not experience heartburn, reflux, or difficulty swallowing. Their only complaint is fatigue, and the anemia is discovered incidentally on routine blood work. This is part of why the diagnosis gets delayed: if you do not have GI symptoms, neither you nor your doctor may think to look at the stomach.

A case report of a child with iron-refractory anemia illustrates this well. The child had no GI complaints, and the hiatal hernia was only discovered after standard causes of iron deficiency had been exhausted. Once the hernia was repaired, iron supplementation finally worked and hemoglobin normalized within months.¹⁰ The case is a reminder that hernia-related iron deficiency is not limited to elderly adults, though it is much more common in that group.

If you have iron deficiency anemia that does not respond to oral supplements, does not have an obvious dietary or menstrual explanation, and keeps recurring despite treatment, a large hiatal hernia belongs on the list of potential causes. A careful upper endoscopy with specific attention to the hiatal region, ideally by a gastroenterologist who is aware of Cameron lesions, can make or break the diagnosis.