The aquatic mammal has been found to have a similar Type 2 diabetes as humans, but can switch off the condition when needed
DOLPHINS OFFER HOPE FOR DIABETICS
Researchers have discovered that dolphins share a similar form of Type 2 diabetes to humans, but that the mammals have the ability to ‘switch off’ the condition when they need to. The findings could pave the way for an eventual cure for the disease, which would benefit thousands of sufferers in the UAE. The country has one of the highest incidences of diabetes in the world, with an estimated 25 per cent of the population having the disorder.
The unexpected discovery was made by scientists in the United States, who were studying blood samples taken from 52 bottle-nosed dolphins. They found that when the dolphins had been made to fast overnight, their blood sugar levels remained high in much the same manner as their land-based diabetic counterparts. However, when they had been fed, the dolphins’ sugar levels returned to normal, unlike in humans with Type 2, or insulin resistant diabetes. It is hoped that the animal’s mechanism for doing this will be discovered, taking scientists closer to finding more effective treatments for the disorder and perhaps even eradicating it entirely.
It is thought that the reason why dolphins maintain intermittent high blood sugar levels is related to their intelligence and diet. The aquatic mammals have very large brains that are only smaller than human brains when corrected for size. These organs require high levels of energy to function effectively, but dolphins consume an almost exclusively high protein diet of fish, which contains little in the way of carbohydrates to provide this necessary fuel. The creatures also go for long periods without eating, so keeping blood sugar levels raised when there is no food available ensures that they have enough energy to hunt for their next meal. Once fed, their insulin resistance then returns to normal to prevent damage.
The human Type 2 diabetic condition is associated with permanently raised blood sugar levels that require dietary changes and medication, as sufferers lack such a mechanism to naturally revert the condition. The elevation is associated with damage to blood vessels and can ultimately lead to a range of health complications, including heart attacks, strokes, kidney damage, eye disorders and amputations.
Scientists think that humans may have developed a similar ability to transiently increase glucose levels in the blood during the last Ice Age, around 20,000 years ago. During this period, edible foliage was harder to find and our ancestors were forced to switch from a predominantly plant-based diet, containing high levels of carbohydrates, to a mainly meat diet from hunting. As with dolphins, this would have kept the large human brains adequately supplied with energy. It is thought that diabetes may have developed from this earlier condition, which would have been a distinct advantage, to one that became a complication associated with the Western diet of sugary, starchy high carbohydrate food.
“It is thought that the reason why dolphins maintain intermittent high blood sugar levels is related to their intelligence and diet. The aquatic mammals have very large brains that are only smaller than human brains when corrected for size.”
The surprise findings from the US study are particularly significant, as there is no ideal animal model of diabetes. Rodents, cats and certain primates, demonstrate similar characteristics of the disease, but none come as close as the insulin resistance model seen in the dolphins. However, the very reason for the similarity of the condition between humans and dolphins — the need to give large brains energy — may well preclude further in-depth research. Both species are intelligent and social creatures and keeping dolphins as laboratory animals for the benefit of mankind would be unethical, despite the potential of finding a cure for such a serious and prevalent condition that affects so many people across the globe.