Apart from humans, dolphins are the only animals to develop a natural form of type 2 diabetes, researchers recently discovered.
An American study found that bottlenose dolphins have insulin resistances similar to that seen in humans. However, unlike humans, dolphins are able to turn the conditions on and off when appropriate, so it doesn’t pose harm to the animal.
Research leader and veterinarian Stephanie Venn-Watson of the US National Marine Mammal Foundation said that these findings could have profound implications for the disease that is linked to one in twenty deaths.
The dolphin could be an invaluable model for researchers to uncover the mysteries of type 2 diabetes. If researchers can figure out how the marine mammals turn off the insulin before it can become harmful, there might be a possible cure involved.
Bottlenose dolphins are “an important, natural and long-lived model for insulin resistance and diabetes,” Venn-Watson told the San Diego conference of the American Association for the Advancement of Science. She hopes the discovery will lead scientists to find a way to prevent, treat and possibly cure diabetes.
She stressed that research does not intend to use dolphins as laboratory animals, but to study their genetic code and physiology through blood and urine samples that could provide important clues about the biological makeup of diabetes.
Researchers made the surprising discovery while studying more than 1,000 blood samples they collected from 52 dolphins. They found that the dolphins’ blood sugar remained at elevated levels when they fasted overnight. Their blood chemistry also changed in ways similar to human diabetics. Although, when the dolphins were fed, their blood reverted to normal, unlike in humans.
Dr. Venn-Watson said that there may be some beneficial reason why dolphins control their own diabetes. Their fish diet is high in protein and low in sugar, and they often go long periods without eating, yet they have very high energy demands and a large brain. By having a resistance to insulin while fasting, they may be able to supply enough sugar to the brain. Once they have eaten, the resistance stops to prevent damage.
“We propose that, while some people may eat high- protein diets to help control diabetes, dolphins appear to have developed a diabetes-like state to support a high-protein diet,” she said.
Dr. Venn-Watson and her team are hoping to find a genetic fasting switch that dolphins may have to turn diabetes on and off. “Finding and controlling such a switch could lead to the control of insulin resistance and possibly the cure to type 2 diabetes in humans,” she added.
High iron that is associated with insulin resistance in humans has also been found in dolphins. The team found that dolphins with excessive iron levels also have high insulin levels that could point to a more damaging form of diabetes. The discovery is significant because no other animal known, besides humans, has such an advanced form of type 2 diabetes.
There is some doubt as to how beneficial dolphins may be pertaining to diabetes research. Mark Simmonds, international head of science at the Whale and Dolphin Conservation Society, posed that ethical issues would arise from dolphins being used to study human diseases, and that they were too distantly related to us to be of any use.
“It is a grave concern that dolphins might be used in biomedical research. Dolphins are intelligent and sophisticated animals, vulnerable to stress and suffering when confined and removed from their natural environment,” he said.
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