Reminder from a GI oncologist: 'Don't ignore anemia or iron deficiency.' Here's why
Key Takeaways
Industry Buzz
"Anemia, specifically a pattern showing iron deficiency anemia, could potentially be a sign of occult blood loss through the GI tract as seen in some cases of colorectal cancer. Anemia can still occur outside of cancer such as diet or chronic disease so it’s important to work it up to determine the cause!" — Olivia Snyder, MD, Instagram handle @liv_snyder
"As a gastroenterologist I’ve been seeing very young patients being diagnosed with colon cancer. Super important not to ignore the signs. One that I’ve seen before is attributing rectal bleeding to hemorrhoids without seeking medical care." — Sarah Altajar, MD, Instagram handle @drsarahaltajar
Find more of your peers' perspectives and insights below.
Iron deficiency anemia? Common. Easy to fix? Usually. But brushing it off as just anemia? That’s where things can get risky. In a recent Instagram post, GI oncologist Laura Vater, MD, MPH, highlighted a troubling trend—the rise of colorectal cancer in younger adults—and why anemia isn’t always as benign as it seems.
We’ve all seen it—patients with mild anemia who assume they just need more iron in their diet. But when a non-menstruating adult presents with iron deficiency, the real question isn’t how to treat it—it’s why it’s happening in the first place.
The anemia we can’t ignore
Iron deficiency is one of the most common nutritional deficiencies, but in younger adults, it can also be an early warning sign of chronic GI blood loss. Patients may feel fine, aside from some fatigue, and assume they just need iron supplements. The problem? If we don’t investigate the underlying cause, we risk missing something serious.
One commenter on Dr. Vater’s post put it plainly:
"It's alarming how colorectal cancer rates are rising in younger adults. Early screening and not ignoring symptoms like anemia or bowel changes could make a huge difference. Definitely a wake-up call for more awareness!"
And they’re right—many patients (and even some providers) don’t associate iron deficiency anemia with a potential hidden bleed. It’s time to change that.
Related: I was diagnosed with colon cancer in my 30s: Here's how I'm coping todayWhen to dig deeper
If a patient under 45 comes in with unexplained iron deficiency anemia, don’t stop at “take iron supplements”—look for a cause.
Here’s when a closer look is warranted:
No clear dietary cause—if their diet isn’t obviously deficient, where’s the iron going?
No history of heavy menstruation–if they don’t menstruate or have light periods, anemia shouldn’t be assumed normal.
Chronic fatigue that doesn’t match their lifestyle—a little tiredness is normal. Persistent exhaustion? Not so much.
Subtle GI symptoms. Even mild, occasional bloating, changes in bowel habits, or discomfort should raise suspicion.
A family history of colorectal cancer or polyps. Ask explicitly—many patients don’t mention it unless prompted.
Bottom line: If you see anemia, ask why
Iron deficiency anemia isn’t always a final diagnosis—it could be a symptom of something else. Whether it’s malabsorption, a slow GI bleed, or something more serious, our job isn’t just to treat the anemia—it’s to find out what’s causing it. Because in some cases, anemia isn’t just anemia—it’s the first warning sign.
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