Low Enzymes, Cancer Spike?

Patient in hospital bed with visitor holding their hand — Photo: Ground Picture / Shutterstock

Doctors have long treated low liver enzyme numbers as good news on a lab report. A new analysis says that assumption deserves a second look, especially for younger adults.

Story Snapshot

Epic Research found adults 18 to 44 with low AST or ALT liver enzyme levels faced a much higher chance of an early-onset colorectal cancer diagnosis.
Low AST below 14 U/L linked to a 65% higher likelihood of early-onset colorectal cancer, and low ALT below 14 U/L linked to a 68% higher likelihood.
Higher enzyme readings showed the opposite pattern, tied to lower cancer likelihood in the same young adult group.
Researchers stress this is an association, not proof that low enzymes cause cancer.

What The New Analysis Actually Found

Epic Research, an analytics firm connected to a major electronic health records company, studied adults aged 18 to 44 getting their first colorectal cancer screening. Patients with AST levels under 14 U/L before screening had a 65% higher likelihood of an early-onset colorectal cancer diagnosis. Those with ALT under 14 U/L saw a 68% higher likelihood. Both comparisons used patients with AST or ALT between 14 and 29 U/L as the baseline group.

The pattern flipped at higher enzyme levels. Adults with AST at 30 U/L or above had a 22% lower likelihood of early-onset colorectal cancer. Those with ALT at 30 U/L or above had a 29% lower likelihood. That means the same blood test, read two different ways, pointed in opposite directions depending on where a patient’s numbers fell on the scale.

Why Liver Enzymes Even Connect To Colon Cancer

AST and ALT are enzymes doctors check to see how the liver is working. Low readings usually get treated as a sign of good health, not a warning sign. This new data challenges that easy assumption for younger patients getting screened for colon cancer, a group where diagnoses have been climbing for years despite falling rates in older adults.

The link is not brand new territory for researchers. A UK Biobank study tracking a large general population found that lower circulating levels of ALT, AST, and other liver-related markers tracked with higher colorectal cancer risk overall, not just in younger patients. Comparing the highest and lowest deciles of enzyme levels, the risk difference ran nearly 40% in that broader population sample.

Where This Fits Among Other Cancer Warning Signs

Colorectal cancer researchers have spent years hunting for blood-based clues that could catch the disease earlier, especially in adults under 45 who often get diagnosed later because doctors don’t expect cancer in that age group. Scientists have tested tools ranging from circulating microRNAs to methylation markers in blood, each aiming to flag risk before symptoms show up or a colonoscopy gets scheduled.

Liver enzyme readings fit into that same search, but with an advantage: doctors already order AST and ALT tests constantly as part of routine bloodwork. That makes this potential warning sign cheap and easy to spot compared to newer genetic tests still working through research pipelines. No extra needle stick, no new lab equipment, just a second look at numbers already sitting in a patient’s chart.

What Researchers Are Not Claiming

Epic Research and outside experts are careful to separate correlation from cause. Having low AST or ALT does not mean a person has cancer, and having higher levels does not guarantee protection from it. The analysis identifies a statistical pattern worth studying further, not a diagnostic test ready for widespread clinical use.

That caution matters, but it should not undercut the practical takeaway. Younger adults experiencing digestive symptoms, family history concerns, or unexplained changes in bowel habits have one more data point worth discussing with a doctor. Common sense says a cheap, already-available blood marker deserves attention, especially when early-onset colorectal cancer keeps rising among Americans who assume they’re too young to worry about it.

The Bigger Picture On Early-Onset Cases

Colorectal cancer in adults under 50 has grown into one of the more alarming trends in American oncology over the past two decades. Researchers have chased explanations ranging from diet and obesity to gut bacteria and genetic mutations, without landing on one single cause. This liver enzyme finding adds another thread to that investigation rather than settling it.

For now, the practical lesson is simple. Routine bloodwork that most adults already get might be quietly flagging risk nobody previously thought to check. Doctors and patients alike may want to start asking more questions about numbers that used to get a passing glance and a clean bill of health.

Further research will need to confirm whether this pattern holds up across larger and more diverse populations before it changes screening guidelines nationwide.