Diabetes and Cancer

People with diabetes are at higher risk of getting cancer. Why is this? What can we do to avoid it?

This question has been important to me lately, because I have had several symptoms of colorectal cancer, including blood in a stool specimen and changed bowel movements. The doctor scheduled a colonoscopy to determine what’s going on, and I’ve been thinking about cancer a lot.

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Colorectal cancer (cancer of the large intestine or rectum) is the third leading cause of cancer death in women in the U.S. and the second leading cause in men. It is one of the types associated with diabetes.

The University of Maryland Medical Center reports that Type 2 diabetes “doubles the risk for developing liver, pancreatic, or endometrial cancer” and increases, to a lesser extent, the risk of cancer of the “colon and rectum, breast, and bladder.”

Scientists wonder what is it about diabetes that raises cancer rates. Most think it is the elevated insulin levels produced by the body in early stages of Type 2.

The cancer connection appears much stronger for Type 2 diabetes than for Type 1, and insulin levels are usually very high in early Type 2 diabetes. Insulin is a growth hormone. It promotes fat storage, stimulates cell division, and helps prevent cell death.

Insulin may act as a growth factor for tumors, helping them grow while discouraging the death of cancer cells. Many types of cancer cells have receptors for insulin on them. Of course, most cells have those receptors, because all cells need glucose, and insulin brings it to them. But these cancer cells seem to have more receptors than most.

Researchers at the American Institute for Cancer Research wrote that high levels of body fat are convincingly linked to the risk of several cancers, including colorectal cancer. Since insulin increases fat storage, insulin could explain the fat/cancer connection, too.

High insulin levels could raise cancer risk independently of body fat, the scientists say. “Research suggests insulin plays an important role in cancer, but it does not have to be a direct link,” said Michael Pollak, MD, a professor at the Department of Oncology and Director of the Cancer Prevention Research Unit at McGill University in Toronto. “There may be other areas that insulin could affect.”

High levels of insulin are linked to increased production of insulin-like growth factor 1 (IGF-1). IGF-1 plays an important role in cell growth, proliferation, and preventing cell death.

Other studies have found, though, that high glucose levels seem to also promote cancer. But in trying to prevent cancer, maybe high glucose levels and high insulin levels are not that different. Cutting way down on carbohydrates should reduce both insulin levels and glucose levels. It seems like good diabetes care will also help prevent cancer, although that can’t be guaranteed.

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While I was still researching this article, I had the colonoscopy two days ago. They didn’t find any cancer! I’m so happy about that. They can’t explain what’s causing the bowel symptoms. They said eat more fiber, but my fiber intake is probably already in the top 3% of American diets.

The colonoscopy wasn’t hard, though the prep was no fun. It was 32 hours of clear liquid diet followed by about six hours of fasting, and drinking a gallon of the prep juice. Hour after hour in the bathroom until everything comes out clear liquid.

The test itself wasn’t bad, maybe because they sedated me with Fentanyl and took away all my pain. I mean all of it, the pain I knew about and the pain I usually don’t let myself feel. You never realize how much pain you’re in until it’s gone.

But it was all worth it. Knowing I don’t have a fatal disease and that I don’t have to go through surgery and chemotherapy feels very good. I have to decide what to do with this extra time God and the Universe have given me.

I get the lesson that it’s worth doing what you can to reduce insulin level and protect your colon with lots of fiber and not eating burned food or chemicals (see my recent post on healthy cooking here.) Life is precious and there’s no reason to give it away sooner than we need to.

When it comes to glucose levels, there’s a difference between monitoring and obsessing, says Scott Coulter. Bookmark DiabetesSelfManagement.com and tune in tomorrow to read more.