Insulin by itself does not cause strokes. However, obesity or poor diet can make cell receptors resistant to insulin. This makes it more difficult for cells to use glucose in the bloodstream as a source of energy. As a result, glucose begins to accumulate and the body produces more insulin. Over time, this can cause a constriction of blood vessels, a condition that may lead to strokes.
Insulin
Insulin is the hormone that ensures that blood sugar, or glucose, is transported into cells for energy use or energy storage. The pancreas secretes insulin in response to a peak in blood sugar levels. Insulin binds to cell receptors embedded in the cell membranes. This leads glucose transporters in the cell to transport glucose into the cells. All cells can use glucose as a source of energy. Muscle and liver cells can store it as glycogen or convert it into fat.
Insulin Resistance
When you constantly overeat or eat too much sugar or simple carbohydrate foods, such as white bread and pasta, your pancreas is working overtime to produce enough insulin. Cells, too, must work hard to convert dietary fuel into fat or glycogen that can be stored. Over time, this makes cells shut down their response to insulin. This condition is known as "insulin resistance." When you are resistant to insulin, it is difficult for your body to carry away glucose from the bloodstream. If the extra insulin that the pancreas secretes cannot remove glucose fast enough, glucose accumulates chronically. This condition is known "type 2 diabetes."
Artery Constriction
Insulin resistance has a number of consequences for your health. The cells in your body do not become resistant to insulin at the same time. Liver cells are the first cells to become resistant. The cells inside your blood vessels are among the last cells to become resistant. When excess amounts of insulin bind to the cells inside your blood vessels, they divide and proliferate. For reasons that are not fully known, this causes plaque formation and constriction of the blood vessels.
Strokes
There are two major types of strokes: ischemic stokes and ruptures. Ischemic strokes occur when a blood vessel in the brain becomes obstructed, and the obstruction prevents blood from passing through. When blood cannot pass through, the neurons that don't receive blood die. When a blood vessel ruptures, blood from the ruptured vessel prevents proper blood circulation in surrounding areas, causing nerve cells to die. As constricted blood vessels are the most common cause of strokes, high blood levels of insulin increase the risk of having a stroke.
