A high-sugar diet is bad news for humans, leading to diabetes, obesity and even cancer. Yet fruit bats survive and even thrive by eating up to twice their body weight in sugary fruit every day.
Now, UC San Francisco scientists have discovered how fruit bats may have evolved to consume so much sugar, with potential implications for the 37 million Americans with diabetes. The findings, published on Tuesday, Jan. 9, 2023 in Nature Communications, point to adaptations in the fruit bat body that prevent their sugar-rich diet from becoming harmful.
Diabetes is the eighth leading cause of death in the United States, according to the Centers for Disease Control and Prevention, and it's responsible for $237 billion in direct medical costs each year.
"With diabetes, the human body can't produce or detect insulin, leading to problems controlling blood sugar," said Nadav Ahituv, PhD, director of the UCSF Institute for Human Genetics and co-senior author of the paper. "But fruit bats have a genetic system that controls blood sugar without fail. We'd like to learn from that system to make better insulin- or sugar-sensing therapies for people."
Ahituv's team focused on evolution in the bat pancreas, which controls blood sugar, and the kidneys. They found that the fruit bat pancreas, compared to the pancreas of an insect-eating bat, had extra insulin-producing cells as well as genetic changes to help it process an immense amount of sugar. And fruit bat kidneys had adapted to ensure that vital electrolytes would be retained from their watery meals.
"Even small changes, to single letters of DNA, make this diet viable for fruit bats," said Wei Gordon, PhD, co-first author of the paper, a recent graduate of UCSF's TETRAD program, and assistant professor of biology at Menlo College. "We need to understand high-sugar metabolism like this to make progress helping the one in three Americans who are prediabetic."
