Why Is Colorectal Cancer Going Up?

Siddhartha Mukherjee says he does not know why colorectal cancer is going up. Peter Attia frames it as the third leading cause of cancer death and asks whether antibiotics, gut health, or obesity are to blame.

Mukherjee's speculation is that the colorectal milieu has changed rapidly in the last few decades. People ingest more forever chemicals, and animal models show that some of them, including chemicals eaten in food, are very pro-inflammatory. He connects the rise to the inflammation theory of cancer, multiplied by a gut microbiome disrupted by antibiotics and other foods. Dennis Burkitt, who discovered Burkitt's lymphoma, went from Oxford to Africa in the 1950s and 60s and virtually found no colorectal cancer, especially in young men and women. Burkitt pointed to a fiber-rich diet that had people emptying the colon twice a day. In the United States, Mukherjee says, people now do so once every two days or three days.

For people who want to avoid colorectal cancer, Mukherjee recommends doubling or tripling fiber intake and cutting exposure to forever chemicals. He also suggests cheap probiotics in the form of live yogurt at least once a week, and he says there is no evidence whatsoever.