Impact of flavonoid-rich black tea and beetroot juice on postprandial peripheral vascular resistance and glucose homeostasis in obese, insulin-resistant men: a randomized controlled trial

Table 3 Effects of interventions on VR of conduit arteries (echo-Doppler), resistance (VOP) and microvessels (NIRS)

Variable/treatment	Time (minutes)
Variable/treatment	−20	+30	+60	+90	+120	+150	+180	LSMeans	P-values
BA VR (echo-Doppler), mmHg ∙ min/ml
Control	117 ± 59	127 ± 70	109 ± 49	119 ± 50	120 ± 52	116 ± 56	125 ± 52	100
Beetroot juice	103 ± 57	89 ± 56	104 ± 66	137 ± 122	109 ± 57	123 ± 114	111 ± 61	98	ns
Black tea	98 ± 41	103 ± 58	88 ± 38	98 ± 44	92 ± 47	94 ± 56	106 ± 52	88	0.008
SFA VR (echo-Doppler), mmHg ∙ min/ml
Control	61 ± 28	53 ± 31	58 ± 39	73 ± 69	61 ± 34	61 ± 55	74 ± 65	54
Beetroot juice	87 ± 67	55 ± 22	49 ± 20	65 ± 56	48 ± 23	63 ± 49	90 ± 105	46	ns
Black tea	63 ± 69	60 ± 58	55 ± 55	51 ± 45	48 ± 32	107 ± 219	42 ± 17	46	0.033
Arm VR (VOP), mmHg ∙ min ∙ 100 ml tissue/ml
Control	54 ± 22	60 ± 27	61 ± 36	62 ± 43	56 ± 28	54 ± 28	56 ± 31	50
Beetroot juice	49 ± 23	53 ± 33	49 ± 20	44 ± 16	46 ± 20	47 ± 18	43 ± 23	44	0.020
Black tea	52 ± 17	55 ± 26	53 ± 22	53 ± 23	51 ± 18	52 ± 22	49 ± 18	48	ns
Leg VR (VOP), mmHg ∙ min ∙ 100ml tissue/ml
Control	44 ± 27	45 ± 20	45 ± 27	45 ± 31	44 ± 31	44 ± 25	44 ± 31	40
Beetroot juice	44 ± 23	42 ± 26	41 ± 27	41 ± 27	44 ± 33	41 ± 30	41 ± 30	35	<0.0001
Black tea	43 ± 19	43 ± 25	42 ± 25	43 ± 29	45 ± 36	43 ± 28	43 ± 22	38	0.041
Arm VR (NIRS), A.U.
Control	129 ± 108	111 ± 66	132 ± 78	122 ± 49	155 ± 167	118 ± 92	124 ± 124	112
Beetroot juice	152 ± 147	125 ± 89	121 ± 91	145 ± 125	170 ± 156	128 ± 101	118 ± 105	105	Ns
Black tea	201 ± 150	149 ± 142	125 ± 77	108 ± 53	133 ± 85	112 ± 69	117 ± 51	84	0.002

Values are means ± SD per time point or LSMeans over all time points, i.e. before (-20) and after 75 g glucose (at 30-min intervals for 3-h); P-values were calculated for the differences in LSMeans compared to control. BA brachial artery; ns: not significant, SFA superficial femoral artery, VR vascular resistance

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