Insulin Resistance and Breast Cancer

It is estimated that between 40% to 50% of American adults have insulin resistance. This condition is characterized by higher levels of the hormone insulin as well as cells that become resistant to its glucose-transporting mechanism. In addition to the risk of prediabetes and Type 2 diabetes, insulin resistance is associated with increased cancer risk for people with obesity and Type 2 diabetes. You can identify insulin resistance through blood tests that demonstrate an increased fasting glucose, elevated fasting insulin, or elevated hemoglobin A1C.

The authors of a recent paper state that elevated circulating insulin levels are associated with increased cancer risk and progression based on epidemiology research. In addition, the authors note that diabetes is a risk factor for several cancers. The study’s authors also recommend caloric restriction and reduced carbohydrates to reduce circulating insulin levels in people with obesity and type 2 diabetes that has cancer. Additionally, I would recommend the diet be rich in fiber (fruits, vegetables, nuts, seeds, legumes) and healthy fats.

Additional research reports that insulin acts as a growth factor on cells, especially cancer cells that commonly have overexpression of their insulin receptors. In addition, elevated insulin levels may increase the activity of bioavailable IGF-1, which is a growth factor that fuels cancer growth.


Dr. Mark Stengler NMD, MS, is a bestselling author in private practice in Encinitas, California, at the Stengler Center for Integrative Medicine. His newsletter, Dr. Stengler’s Health Breakthroughs, is available at His clinic website is