Eating dinner near bedtime when endogenous melatonin ranges are excessive is related to decreased insulin secretion and decreased glucose tolerance, which enhance the danger of type 2 diabetes.
And people who find themselves carriers of the G allele of the melatonin receptor-1b gene (MTNR1B) have better impairment in glucose tolerance after consuming a late dinner.
“In natural late eaters [in Spain], we simulated early and late dinner timing by administering a glucose drink and compared effects on blood sugar control over 2 hours,” mentioned senior creator Richa Saxena, PhD, a principal investigator on the Center for Genomic Medicine at Massachusetts General Hospital, Boston.
The examine additionally in contrast outcomes in carriers and noncarriers of the G allele variant of the melatonin receptor gene, Saxena identified, in a press launch from the hospital.
“We found that late eating disturbed blood sugar control in the whole group,” added lead creator Marta Garaulet, PhD.
“This impaired glucose control was predominantly seen in genetic risk variant carriers, representing about half of the cohort,” mentioned Garaulet, professor of physiology and diet, University of Murcia, Spain.
The examine outcomes “may be important in the effort towards prevention of type 2 diabetes,” in accordance with co-senior creator Frank A.J.L. Scheer, PhD.
“Our findings are applicable to about a third of the population in the industrialized world who consume food close to bedtime, as well as other populations who eat at night, including shift workers, or those experiencing jetlag or night-eating disorders, as well as those who routinely use melatonin supplements close to food intake,” mentioned Scheer, director of the Medical Chronobiology Program at Brigham and Women’s Hospital, Boston, Massachusetts.
“Notably, our study does not include patients with diabetes, so additional studies are needed to examine the impact of food timing and its link with melatonin and receptor variation in patients with diabetes,” Scheer mentioned.
The findings, from the MTNR1B SNP*Food Timing Interaction on Glucose Control (ONTIME-MT) randomized crossover examine, had been recently published in Diabetes Care.
Melatonin Plays a Key Role in Glucose Metabolism
Melatonin, a hormone primarily launched at night time that helps management the sleep–wake cycle, usually rises round 2 hours earlier than bedtime, the researchers clarify.
The discovery of MTNR1B as a sort 2 diabetes-associated gene “suggests that beyond sleep and circadian regulation, melatonin plays a key role in glucose metabolism,” they notice.
However, whether or not melatonin improves or impairs glucose management is controversial, and the impact of MTNR1B genotypes on glucose management is just not clear.
“We decided to test if late eating that usually occurs with elevated melatonin levels results in disturbed blood sugar control,” Saxena defined.
To examine this, researchers enrolled 845 adults in Spain who had been 18-70 years previous and didn’t have diabetes.
Participants had been a imply age of 38 years and 71% had been ladies. They had a imply physique mass index (BMI) of 25.7 kg/m2 and 18% had obesity.
On common, they usually ate dinner at 21:38 (9.38 PM) and went to mattress at 24:32 (0.32 AM).
DNA evaluation from members’ blood samples decided that fifty% had the CC genotype of the MTNR1B gene, 40% had the CG genotype, and 10% had the GG genotype.
Each participant underwent two oral glucose tolerance checks.
They fasted for 8 hours after which had a 2-hour 75-g oral glucose tolerance check both 1 hour earlier than bedtime (simulating a late dinner) or 4 hours earlier than bedtime (simulating an early dinner).
Then they repeated the check on the reverse supper time on one other night time.
The common serum melatonin values had been 3.5-fold larger after the late dinner than after the early dinner, leading to 6.7% decrease insulin space beneath the curve (AUC) and eight.3% larger glucose AUC.
Genotype variations in glucose tolerance had been attributed to reductions in beta-cell perform.
“Our results confirm that late eating acutely impairs glucose tolerance through a defect in insulin secretion,” the researchers reiterate.
ONTIME-MT was funded by the National Institutes of Health, the Spanish Government of Investigation, Development, and Innovation, and the Seneca Foundation. The researchers have reported no related monetary disclosures.
Diabetes Care. Published on-line January 10, 2022. Abstract
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