Topic summary contributed by volunteer(s): John

Insulin is one of a number of hormones that regulate how the body uses sugar, fat, and amino acids (building blocks of protein).

How Insulin Works

When blood sugar rises after a meal, the pancreas releases insulin into the blood, which moves sugar (glucose) out of the blood and into the cells of the body, including converting glucose to fat, among other things. The blood sugar then drops to normal levels. Sometimes it overshoots, causing symptoms of hypoglycemia (low blood sugar). Insulin deficiency leads to high blood sugar.

Insulin and Diabetes

In diabetes mellitus, there is a relative insulin deficiency. It is treated with medications like insulin, oral hypoglycemics, or both.  So when blood sugar rises after a meal in a patient with diabetes, it may not drop back down to normal levels–either because the pancreas cannot make enough (Type I); or the body’s cells are so resistant to the existing insulin that they can’t remove the glucose from the bloodstream (Type II). Insulin resistance also usually exists in Type I. Prediabetes is a state of borderline diabetes that may progress to diabetes. Diabetes is a strong risk factor for high cholesterol, vision problems (retinal damage), and cardiovascular health.  We now know that animal (not plant) fat, like that found in meat, can increase insulin resistance shortly after ingestion and for hours later, causing blood sugar to rise more than it would have in the absence of animal fat.

There is evidence that diabetes can be prevented, and in many cases of Type II diabetes (and some adult-onset Type I) can be resolved, with plant-based diets.  Weight loss itself, independent of plant-based eating, also helps.

Insulin-like Growth Factor

Dairy has growth hormones in it, that cause our bodies to secrete additional insulin-like growth factor (IGF), which may stimulate cell growth and have some insulin effect also. In adolescence, a period of rapid growth, it is normal that IGF levels are among the highest in one’s life.  But after we are fully grown, high IGF is abnormal, and may promote growth of tumor cells or cancer cells.  

The information on this page has been compiled from the research presented in the videos listed. Sources for each video can be found by going to the video’s page and clicking on the Sources Cited tab.