Insulin may cause tumors to grow faster

Abdominal obesity, prediabetes, and type 2 diabetes carry an increased risk for cancer. One likely explanation for the risk increase is that high insulin levels in the blood trigger the body’s growth system. Theoretically, a diet that lowers insulin levels could help more people survive their cancer. The Dietary Science Foundation wants to investigate this through well-constructed scientific studies.

Someone who has abdominal fat, prediabetes or type 2 diabetes can have ten times more insulin in their blood after a meal than a healthy person. Insulin not only lowers blood sugar but also stimulates cell growth. In addition, insulin activates another important growth factor in the body: IGF-1. Most cancer cells have receptors for both insulin and IGF-1 on their surfaces. When growth factors attach to these receptors, the cells are given a signal that they should grow.

This biochemical mechanism may explain why people with abdominal fat, prediabetes and type 2 diabetes have a higher risk of getting certain kinds of cancer, and why it’s often a more aggressive form.

There are studies that suggest that dietary glycemic index might affect the development of cancer, but they are too few and too small. The research needs to be strengthened. If you want to support our fight against cancer, please join us as a one-time or monthly donor. In this way, you help us in our long-term efforts.

References to studies linking abdominal fat, prediabetes or type 2 diabetes to cancer:

Metabolic Dysregulation of the Insulin–Glucose Axis and Risk of Obesity-Related Cancers in the Framingham Heart Study-Offspring Cohort (1971–2008)

Prediabetes and the risk of cancer: a meta-analysis

Longitudinal associations of blood markers of insulin and glucose metabolism and cancer mortality in the third National Health and Nutrition Examination Survey

Therapy insight: Influence of type 2 diabetes on the development, treatment and outcomes of cancer

Blood glucose and risk of incident and fatal cancer in the metabolic syndrome and cancer project (megan): analysis of six prospective cohorts

Studies linking high blood sugar and high insulin levels to cancer and a more aggressive progression of the disease:

Fasting insulin and outcome in early-stage breast cancer: results of a prospective cohort study

Fasting serum glucose level and cancer risk in Korean men and women

Glucose as a prognostic factor in ovarian carcinoma

Glucose as a prognostic factor in non-diabetic women with locally advanced cervical cancer

Insulin, the insulin-like growth factor axis, and mortality in patients with nonmetastatic colorectal cancer

Studies linking the glycemic index of the diet to cancer development:

Impact of consumption of vegetable, fruit, grain, and high glycemic index foods on aggressive prostate cancer risk