Researchers recognized some time ago that there’s a link between sleep deprivation, weight gain and the onset of Type 2 diabetes.
A new study from the University of Chicago may have identified the mechanism tying those three conditions together.
Researchers led by Dr. Esra Tesali, a physician at the University of Chicago Medical Center and lead author of the study, found that sleep deprivation led to elevated levels of certain fatty acids in the blood and pre-diabetic conditions in healthy young men.
“At the population level, multiple studies have reported connections between restricted sleep, weight gain, and type 2 diabetes,” Tasali said in a university press release. “Experimental laboratory studies, like ours, help us unravel the mechanisms that may be responsible.”
The study adds weight to the theory that lack of sleep disrupts the body’s ability to metabolize fat and reduces insulin’s ability to regulate blood glucose levels. The findings also suggest that just getting enough sleep ““ a rarity for many ““ could turn around the twin epidemics of obesity and Type 2 diabetes, researchers said.
Usually, fatty acid levels in the blood peak and then recede overnight during sleep. But researchers found that after three nights of getting only four hours of sleep, fatty acid levels in test subjects’ blood remained elevated from about 4 a.m. to 9 a.m. While the fatty acids remained high, the ability of subjects’ natural insulin to regulate blood glucose levels was impaired.
The study included 19 healthy males ages 18 to 30. They were divided into two groups: One got a full night’s rest of 8.5 hours in bed for four consecutive nights the second group spent just 4.5 hours in bed.
Blood samples were collected from all of the participants, and all ate the same healthy diet. Researchers found that in the sleep-restricted group, fatty acid levels were 15 to 30 percent higher during the light night and early morning hours. Fatty acid levels that were elevated from about 4 a.m. to 6 a.m. were correlated with an increase in insulin resistance ““ a hallmark of pre-diabetes ““ that lasted for nearly four hours.
Sleep restriction prolonged the secretion of a growth hormone and increased stress hormones, which both increase fatty acid levels.
Insulin levels were unchanged in the sleep-restricted subjects, but their insulin’s ability to regulate blood glucose levels declined 23 percent after their restricted sleep, suggesting an insulin-resistant state, researchers said.
The study was published Feb. 19 in the online edition of Diabetologia.
The types of fatty acids researchers studied are an important energy source for the body. They’re usually only seen at elevated levels in obese people or in individuals with Type 2 diabetes or heart disease.