Vitamin C preserves endothelial function in patients with coronary heart disease after a high-fat meal.
BACKGROUND
It has been suggested that an oxidative mechanism is involved with the impaired endothelium-dependent vasodilatation that occurs after a high-fat meal.


OBJECTIVE
The study was undertaken to evaluate the effect of a single oral dose of vitamin C (2 g) on postprandially impaired endothelium-dependent vasodilatation in patients with coronary heart disease (CHD).


METHODS
This study included 74 patients with CHD and 50 subjects without CHD with risk factors. The two groups were divided into two subgroups that did or did not receive 2 g of vitamin C (CHD/VitC and CHD/control, n = 37; non-CHD/VitC and non-CHD/control, n = 25) after a high-fat meal (800 calories, 50 g fat). Serum levels of triglyceride, total cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol in the fasting state and at 2, 4, 5, and 7 h after the high-fat meal were measured. Endothelial function was assessed in the brachial artery by high-resolution ultrasound at baseline and at 4 h postprandially.


RESULTS
The postprandial serum triglyceride concentration increased significantly at 2-5 h after the high-fat meal in all groups. The fasting flow-mediated dilatation (FMD) (p < 0.02) and nitroglycerin-induced dilatation (NID) (p < 0.05) of patients with CHD were impaired compared with those of non-CHD subjects. Postprandial FMD was significantly aggravated in the non-CHD/control group (p < 0.01) and the CHD/control group (p < 0.001), but the postprandial FMD in patients and subjects taking vitamin C showed no significant change, although the CHD/VitC group had a mild tendency toward improvement (p = 0.064) and non-CHD/VitC group had a mild tendency toward aggravation (p = 0.852). The change of NID after a high-fat meal did not reach statistical significance in the four groups. The decrement of postprandial FMD correlated positively with the increment of 2-h serum triglyceride concentration in the patients without vitamin C (n = 62, r = 0.545, p < 0.001).


CONCLUSIONS
The postprandial state after a high-fat meal is critical in atherogenesis, as it induces endothelial dysfunction through an oxidative stress mechanism. Vitamin C treatment has a promising benefit for patients with CHD.
Ling
Liu
L
Department of Cardiology, Second Affiliated Hospital, Central South University, People's Republic of China.
Zhao
Shui-Ping
SP
Gao
Mei
M
Zhou
Qi-Chang
QC
Li
Yu-Ling
YL
Xia
Bing
B
D000284:Administration, Oral; D000704:Analysis of Variance; D000975:Antioxidants / Q000008:administration & dosage*; D001205:Ascorbic Acid / Q000008:administration & dosage*; D001916:Brachial Artery / Q000502:physiology; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D003327:Coronary Disease / Q000503:physiopathology*; D004041:Dietary Fats / Q000009:adverse effects / Q000494:pharmacology*; D004730:Endothelium, Vascular / Q000502:physiology*; D005260:Female; D006801:Humans; D008055:Lipids / Q000097:blood; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress; D019518:Postprandial Period; D012307:Risk Factors; D014664:Vasodilation / Q000502:physiology
D000975:Antioxidants; D004041:Dietary Fats; D008055:Lipids; D001205:Ascorbic Acid