A diet that mimics fasting temporarily put mice in a starvation state, reversing diabetes in the animals, according to a new study. The diet was also shown to reduce the risk factors in people with pre-diabetes
Research by investigators at the University of Southern California showed the special, fasting-mimicking diet triggers the development of insulin-producing cells in mice with diabetes. The study was published in the journal Cell.
In humans, an earlier study of the diet reduced the risk factors of diabetes, such as elevated blood sugar, in people who were headed toward development of the disease. An article on the diet in humans appeared in Science Translational Medicine.
In both Type 1 diabetes and in the later stages of Type 2 diabetes, the beta cells of the pancreas are destroyed. But the authors said the diet appears to "reboot" the body, switching on genes that trigger the release of stem cells, master cells responsible for organ development.
More than fasting required
However, fasting alone is not the key to restoring insulin levels. Scientists said refeeding after the brief starvation diet, with specially calibrated nutrients, is critical to kickstarting the production of new beta cells.
The process of stem cell activation is the same as seen in embryos to stimulate organ growth, according to gerontology professor Valter Longo, the director of USC's Longevity Institute and senior author of both studies. He said the fasting-mimicking diet can be used to reprogram cells without any genetic alterations.
"So basically the system is using some of the same program that we use during embryonic and fetal development to regenerate the pancreas once the food comes back around," he said. "And that's the trick. It's not so much the starvation. It's really the combination of the starvation and the refeeding." And, he stressed, "the refeeding's got to be a high-nourishment one."
Study participants put on the high-fat, low-calorie, low-protein diet consumed between 800 and 1,100 calories daily for five days in a row each month for three months. After each fast, they were refed with nutrient-rich foods.
Researchers found fasting triggered the production of a protein called Ngn3, which generated new, healthy beta cells that secreted insulin. They saw production of insulin in a dish in pancreatic cells extracted from mice and from healthy human donors and patients with both types of diabetes.
Scientists found the diet replaced damaged insulin-producing cells with new functioning ones in mice placed on the diet for four days.
Heart disease, cancer risks
The investigators have also amassed evidence that the fasting-mimicking diet reduces the risk of age-related diseases, including heart disease and cancer. It may also hold benefits for people with multiple sclerosis, said researchers.
But Longo said people with diabetes should not try the diet at home yet because it can drop blood sugar to perilously low levels if they don't know what they are doing. "We warn people that, particularly [for people with] Type 1 or patients that inject themselves with insulin, it can be very risky or even lethal," Longo cautioned.
He said investigators were poised to begin larger human clinical trials of the fasting-mimicking diet in the next six months.