When type 2 diabetes patients skipped breakfast, they had higher levels of glucagon and free fatty acids (FFA), and reduced levels of insulin, C-peptide, and intact glucagonlike peptide-1 (iGLP-1) after meals, compared with when they ate breakfast, according to a randomized, open-label, cross-over-within-subject clinical trial.
A total of 22 overweight or obese people who had type 2 diabetes completed the study. Patients could not be taking GLP-1 analogs, anorectic drugs, steroids, or oral hypoglycemic agents, other than metformin. Seven of the patients had a history of hypertension and were treated with ACE inhibitors and/or calcium antagonists, wrote Dr. Daniela Jakubowicz of the Diabetes Unit in Hospital de Clinicas in Caracas, Venezuela.
At the Diabetes Unit, the patients participated in 2 full days of testing, separated by a washout period of 2-4 weeks. On one of the days, patients consumed three meals, including breakfast. On the other testing day, patients fasted until 1:30 p.m., consuming only lunch and dinner. All patients ate each of their meals during the same scheduled times; all meals contained identical macronutrient content and composition.
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Areas under the curve of data values for tested measures during an early response interval (0-30 minutes after eating a meal) and 0-180 minutes after eating a meal were calculated by the trapezoidal rule. These calculations were used as an estimate of response to meal consumption.
Plasma levels for glucose, insulin, C-peptide, and iGLP-1 were, respectively, 16.5%, 45%, 50%, and 33% higher before lunch, on the day that patients consumed breakfast, than they were on the day that they skipped breakfast.
The plasma FFA level was 1,787.1% higher for study participants on the day when they fasted until lunch than it was on the day when they ate breakfast. During tests taken 60-180 minutes after consumption of breakfast, patients’ glucagon levels were 12.5% lower than those of patients who fasted before lunch.
On the day that patients skipped breakfast, insulin was 17% lower after lunch and 7.9% lower after dinner, compared with the amounts of insulin found on the day that patients ate breakfast; iGLP-1 was also lower after dinner (16.5%) on the day that patients skipped breakfast.
After lunch and dinner, glucagon levels were 9.7% and 11.5% higher, respectively, on the day that patients refrained from eating breakfast than on the day that patients ate breakfast. Following lunch and dinner on the day that patients skipped breakfast, FFA values were higher (41.1% and 29.6%, respectively).
“We showed that the deleterious effects of breakfast omission triggering hyperglycemic response occurred after lunch and dinner, but the exact duration of this effect is not known,” wrote Dr. Jakubowicz and her colleagues. “In addition, the role of insulin sensitivity, suppression of hepatic glucose production, gastric emptying, and clock gene expression remain undefined.”
Read the full study in Diabetes Care (doi:10.2337/dc15-0761).