Why Your Oncologist May Not Talk About Insulin

And What the Science Actually Shows

Here’s something that should make you angry: The connection between insulin and cancer growth has been studied in major journals for decades, yet most oncologists don’t test for it and weren’t trained to look for it. This is just like the link between exercise and cancer, which was clear in the sports medicine journals but nowhere in oncology.

Dr. Mary Ann Martin sat across from me and said something that stopped me cold: “I was never taught the connection between how cancer can grow in an environment where insulin is left unchecked.” She’s an endocrinologist. This is supposed to be her territory. If she wasn’t taught this connection, what chance does your primary care doctor have?

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But the research is unambiguous. Let’s look at what we actually know.

The Science Behind Insulin as Tumor Fuel

When Dr. Martin describes insulin as “fertilizer” for cancer - use a little, great; use too much, dangerous weeds start growing - she’s simplifying a well-established biological mechanism. Insulin doesn’t just shuttle glucose into cells. It activates growth pathways.