Hindi ko sure kung ang vitamins ang culprit, pero totoo na may mga factors na nagpa-spike ng morning blood sugar, stress, hormones, even lack of sleep pwedeng mag-trigger nito kaya sulit na talaga mag-check ka with your doctor para malaman kung ano exactly ang nangyayari, especially since controlled naman yung after-meal readings mo which is actually good! One of my mum friends with similar concerns discovered na ang timing ng dinner niya and how much protein she ate was making a difference, so worth exploring yun din with your doctor para ma-rule out or ma-confirm kung ano talaga ang cause.