Diabetes and Cancer

Diabetes and Cancer

The Diabetes and Cancer Connection

I will explore the Insulin and Diabetes Connection to Cancer, and address these questions;

  • How are diabetes and cancer connected?
  • How are insulin levels connected to cancer?
  • Which cancers have insulin receptors?
  • How do I use this information to reduce my risk?

This blog does not substitute as medical advice.

Diabetes and Cancer

Are these two seemingly different conditions related? According to the author of several papers on the connection, having diabetes will put a person at higher risk of developing certain cancers. These are cancers of the liver, pancreas, kidney, endometrium, colon or rectum, bladder, non-Hodgkin’s lymphoma and breast.

What is Responsible for the Increased Cancer Risk in People with Diabetes?

Diabetes provides two crucial elements that help to initiate cancer and keep it progressing and those are;

  • high blood sugar levels
  • high insulin levels

The mechanism that seems to be the biggest driver of cancer growth is high insulin levels.

High Insulin Levels

This condition is called hyperinsulinemia (hyper=higher and emia= in the blood). What is the mechanism in which higher than normal levels of insulin promotes cancer? There are three mechanisms postulated and these are;

  1. Firstly, insulin will cause a decrease in insulin-like growth factor (IGF-1) binding proteins. IGF-1 is a growth promoter, when its binding protein is kept busy by insulin it is free to circulate in the bloodstream at higher levels. This results in more IGF-1 available to promote the growth of cancer cells.
  2. Secondly, cancer cells have a greater number of insulin receptors. Insulin will dock into these receptors (like parking places) and this docking triggers the cells to undergo mitosis. Mitosis is the process of cell division in which a parent cell replaces itself with two identical daughter cells. This process is growing the cancer.
  3. Third and finally, higher levels of insulin. This is a hallmark of both prediabetes and type 2 diabetes and results from a condition called insulin resistance. When your body’s normal cells are resistant to insulin, this creates higher than normal insulin levels and this insulin can then find its way to insulin receptors on cancer cells. When insulin docks onto cancer cells it amps up cell division, putting this process into hyper drive and causing the cancers to grow rapidly.

Which Cancers Have Insulin Receptors?

Researchers from the University of Magna Craecia of Catanzaro, Italy have published a thorough review of the connection between insulin receptors and cancer progression (2).

According to their summary, the following cancers have insulin receptors:

  • Breast
  • Thyroid
  • Colon
  • Ovarian
  • Prostate
  • Sarcomas

What Can I Do To Reduce my Risk of Cancer? 

  1. If you have type 2 diabetes and are taking medication for it, you should know that some diabetes medication works by making your body produce more insulin. For example, the sulfonylureas would increase insulin. In contrast metformin and thiazolidinediones decrease insulin levels. If you currently have type 2 diabetes and want to decrease your cancer risk, talk to your doctor about using metformin as your treatment of choice.
  1. Excess body fat leads to more insulin resistance. To reverse this and improve the insulin sensitivity of your cells, begin a weight loss program that includes a healthy balanced diet combined with regular moderate exercise. Intermittent Fasting is a weight loss program that can also reduce insulin resistance more than traditional calorie restricted diets can.
  1. To achieve better control of blood sugars and insulin follow an eating plan that minimizes spikes in your blood sugar level. This means eating a diabetic diet even if you don’t have diabetes. This would be an eating plan that includes:
  • Minimizing sweets like soda pop, candies and added sugars
  • Choosing more whole grains (these are also called low glycemic) instead of refined and processed carbohydrate (called high glycemic). For example, choose whole grain bread over white bread, choose brown rice over white and choose whole flours for baking and not all purpose flour
  • Choosing fruits and vegetables over juice
  • Balancing your meals and snacks with a protein and carbohydrate choice. For example, instead of a fruit at snack combine a fruit with some nuts.
sugar on spoon
Minimizing adding sugars in the diet is a healthy strategy.
  1. You can make your cells more sensitive to insulin (less resistant) by regular moderate exercise.

References for Diabetes and Cancer

Diabetes and Cancer. Vigneri P1, Frasca F, Sciacca L, et al. Endocr Relat Cancer. 2009 Dec;16(4):1103-23.

Insulin receptor and cancer. Belfiore A and Malaguarnera R. Endocr Relat Cancer. 2011 Jul 4;18(4):R125-47.

Diabetes and cancer: is diabetes causally related to cancer? Suh S, Kim KW

Diabetes Metab J. 2011 Jun;35(3):193-8.