How Grizzly Bears May Help Prevent Diabetes

Imagine eating 20,000 calories a day, gaining 50 pounds a week, then not moving for several months. Your health would suffer, to say the least. But that’s what grizzly bears do every fall. And they have no ill effects.

Grizzly bears, found in the western U.S. and Canada, go through three stages in a year: active, hyperphagia, and hibernation. After mating and caring for young in the spring and summer, they transition into hyperphagia in the fall, when their energy is devoted to eating as much as possible. They begin hibernating in early winter and rely on their fat deposits to sustain them through the next several months. Their metabolic rate, heart rate, and body temperature decrease, and they become insulin resistant.

Insulin is a hormone that regulates the body’s blood sugar levels. It tells the liver, muscle and fat cells to absorb blood sugar, a source of energy. But weight gain and an overabundance of blood sugar can cause the cells to stop responding, become resistant to insulin and no longer absorb blood sugar. The higher blood glucose level is a leading cause of Type 2 diabetes, a disease which can lead to heart attacks, strokes and blindness.

Bears differ from humans in that they can control their insulin resistance, turning it on and off like a switch. Scientists at the Washington State University Bear Center studied the blood of hibernating bears to learn how this feat is accomplished. They found eight key proteins that seem to have a unique role in bears, working either independently or together to regulate insulin during hibernation. The next study will attempt to find exactly what the proteins are controlling. Since humans and bears have many of the same genes, understanding the role of these proteins could teach us more about human insulin resistance. Eventually, we may be able to manipulate the eight proteins in humans to prevent diabetes.