Breakfast skipping suppresses the vascular endothelial function of the brachial artery after lunch

Breakfast skipping has been suggested to be associated with cardiovascular diseases. However, whether breakfast skipping affects vascular endothelial function (VEF), a marker of cardiovascular diseases, remains unclear. This study aimed to investigate the impact of breakfast consumption (Eating trial) and skipping (Skipping trial) on brachial artery (BA) VEF in healthy breakfast eaters. A total of nine healthy individuals (4 females and 5 males) either had breakfast between 830 and 900 or skipped it and had lunch between 1200 and 1230, followed by a 3-h rest period until 1530. For BA VEF evaluation, flow-mediated dilation (FMD) was measured by ultrasound before and after breakfast and lunch. FMD was calculated as the percent change in BA diameter normalized to the shear rate area under the curve (FMD/SR_AUC). Blood glucose, plasma insulin, and plasma free fatty acid levels in capillaries were measured before and after breakfast and lunch. At 1530, the Eating trial, but not the Skipping trial, significantly increased FMD/SR_AUC from baseline (<i>P</i> = 0.006). The Skipping trial showed significantly lower changes in FMD/SR_AUC from 830 than the Eating trial at 1530 (<i>P</i> < 0.001). We found a significant inverse correlation between changes in FMD/SR_AUC between 830 and 1530 and peak glucose levels after lunch (<i>r</i> = -0.882, <i>P</i> < 0.001) and with an incremental area under the curve for glucose between 830 and 1530 (<i>r</i> = -0.668, <i>P</i> < 0.001). These results suggest that a single bout of breakfast skipping can suppress BA VEF in the afternoon because of postlunch hyperglycemia.<b>NEW & NOTEWORTHY</b> Skipping breakfast does not affect vascular endothelial function (VEF) before lunch. However, after lunch on normal meals (i.e., not oral glucose tolerance test), VEF was found to be lower in those who skipped breakfast than those who ate breakfast. Such reduced postlunch VEF after skipping breakfast was associated with postprandial hyperglycemia. These results provide important insight into the impact of eating breakfast on VEF and glycemic control in healthy adults.