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作者：Thomas R. Collins  
出處：WebMD醫學新聞

　　April 19, 2010（奧地利維也納）－根據第45屆歐洲肝臟研究學會年會，由瑞士與西班牙研究人員公佈的研究結果，黑巧克力可以幫助減低肝硬化病人餐後肝臟壓力。
　　
　　一個小型、收納22個病患的研究發現，在用餐中不論接受白巧克力或黑巧克力，都明顯增加肝門靜脈壓力梯度（HVPG）。
　　
　　然而，比起餐前，11位接受白巧克力的病人，其HVPG的平均變化為4毫米汞柱，而黑巧克力組則是1毫米汞柱（P = .02）。
　　
　　於瑞士伯恩臨床藥理與臟器研究機構擔任新進教員的Andrea De Gottardi博士向現場的聽眾表示，雖然肝臟血流或肝門靜脈血流在黑巧克力或白巧克力組上升的差不多，但餐後HVPG在黑巧克力組明顯較低。
　　
　　Gottardi博士解釋，黑巧克力使肝內血管擴張，致使肝門血流增加，減弱飯後HVPG的上升。
　　
　　進食帶來血管擴張，在肝硬化病患可能造成HVPG嚴重上升，主要是由於受損的肝內血管擴張的適應性反應導致快速血流增加。功能不良伴隨的是肝臟一氧化氮的可用率降低。
　　
　　抗氧化劑具有減弱飯後HVPG上升的效果。可可含有異黃酮具有抗氧化效果，但富含異黃酮的黑巧克力還未在肝硬化病人得到驗證。
　　
　　在本研究中，病人被隨機分成兩組，每組各11個人；而兩組在HVPG、肝門靜脈血流或肝血流方面無明顯差異。
　　
　　液狀巧克力餐包含0.55克頂級瑞士蓮黑巧克力及0.63克頂級白巧克力兩組。這包含了相同的熱量、蛋白質、脂肪及碳水化合物及類似的體積。
　　
　　所有病患的餐點同時包括接受200毫升的亞培安素。
　　
　　所有病患在肝門靜脈血流、肝血流與HVPG比起試驗前都明顯增加。
　　
　　白巧克力與黑巧克力組在肝門靜脈血流與肝血流無明顯差異，但在HVPG增加的幅度卻不同。
　　
　　白巧克力組HVPG在餐前略為增加超過15毫米汞柱，飯後則增加至約20毫米汞柱（P = .003）。黑巧克力組在餐前HVPG是15毫米汞柱，飯後則增加約1毫米汞柱，並無顯著增加（P = .07）。
　　
　　研究人員也發現，白巧克力組與黑巧克力組在平均動脈壓變化明顯不同。在黑巧克力組大約增加了7%，但在白巧克力組卻沒有增加。
　　
　　Gottardi博士表示，由於黑巧克力還增加平均動脈壓，它可能對全身都有幫助。
　　
　　德國漢威諾醫學院肝膽腸胃與內分泌科的資深醫生與助理教授、且擔任EASL秘書長的Heiner Wedemeyer博士認為應該注意這項數據，到目前為止是有限的。
　　
　　Heiner Wedemeyer指出，這是一個小型，也是第一個想到可能有影響的研究，就跟咖啡的故事一樣，咖啡對肝臟有益，且越多越好，因此是劑量效應。我們已經知道某些事情每天在說的，可能就是有幫助的。
　　
　　他表示，這項研究可能往相同方向，但還有很多是需要學習的。
　　
　　Wedemeyer評論，我想要看更多數據，去看看機轉方面的數據，以得到實際上是什麼特定細胞類型的影響來解釋這結果。
　　
　　本研究未接受商業贊助。Gottardi與Wedemeyer博士宣稱沒有相關資金的往來。


Dark Chocolate Helps Lower Hepatic Blood Pressure in Cirrhosis Patients

By Thomas R. Collins
Medscape Medical News

April 19, 2010 (Vienna, Austria) — Dark chocolate helps to keep down blood pressure after meals in the liver of cirrhosis patients, according to research unveiled here at the European Association for the Study of the Liver (EASL) 45th Annual Meeting by Swiss and Spanish researchers.

In a small study of 22 patients who received a meal that included either white chocolate or dark chocolate, there was a significant increase in the hepatic venous portal gradient (HVPG) in the overall population.

However, the 11 patients in the white chocolate group had an average change in HVPG of almost 4 mm Hg compared with their premeal level, whereas the dark chocolate group saw a change of just over 1 mm Hg in HVPG (P = .02).

"The postprandial increase in HVPG was significantly lower in the dark chocolate group, while hepatic blood flow and portal vein blood flow increased similarly in both dark and white groups," Andrea De Gottardi, MD, PhD, a junior faculty member at the Institute of Clinical Pharmacology and Visceral Research in Bern, Switzerland, told audience members in discussing the results.

"Dark chocolate attenuated the postprandial increase in HVPG by allowing intrahepatic vasorelaxation in response to the increase in portal blood flow," Dr. Gottardi explained.

Eating brings about vasodilation, which, in cirrhotic patients, can cause a dangerous increase of the HVPG, caused by an impaired intrahepatic vasodilatory adaptive response to rapid increases in blood flow. The dysfunction is accompanied by a decreased availability of nitric oxide in the liver.

Antioxidants have been shown to blunt the postmeal increases of HVPG. Cocoa has high levels of flavonoids that have potent antioxidant properties. But flavonol-rich dark chocolate had not been tested for its effects on HVPG in cirrhotic patients.

In the study, patients were randomly split into 2 groups of 11. At baseline, there were no significant differences in HVPG, portal vein blood flow, or hepatic blood flow.

The liquid chocolate meal included 0.55 g of Lindt Excellence dark chocolate for one group and 0.63 g of Lindt Excellence white chocolate for the other group. Those amounts contained virtually the same levels of energy content, proteins, fat, and carbohydrates and had similar volumes.

All patients were also given 200 mL of Ensure Plus to complete their meals.

Portal vein blood flow, hepatic blood flow, and HVPG all increased significantly from baseline for the whole patient population.

There were no significant differences between the white and dark chocolate groups in the increase in portal vein blood flow and hepatic blood flow, but there was a significant difference in the increase in HVPG between the 2 groups.

The white chocolate group's HVPG increased from a little more than 15 mm Hg before the meal to about 20 mm Hg after the meal (P = .003). The dark chocolate group's HVPG was 15 mm Hg before the meal and increased only about 1 mm Hg, not a significant increase (P = .07).

Researchers also found there was a significant difference between the white and dark chocolate groups in the mean change in arterial pressure. There was a jump of about 7% in arterial pressure in the dark chocolate group, whereas there was no increase in the white chocolate group.

"Since dark chocolate also increased mean arterial pressure, it also may exert beneficial system effects," Dr. Gottardi said.

Heiner Wedemeyer, MD, senior physician and assistant professor in the Department of Gastroenterology, Hepatology, and Endocrinology at Hanover Medical School in Germany and the secretary general of EASL, cautioned that the data, so far, are limited.

"It's a small study. It's the first to think that there might be an effect," said Heiner Wedemeyer. "Just look at it about coffee —?the coffee story. Coffee is good for the liver. And the more, the better. So there's a dose effect. So we know already that certain things that we are taking on a daily basis might be beneficial."

This study is probably going in the same direction but more needs to be learned, he said.

"I want to see more data, I want to see mechanistic data, what is actually the effect on specific cell types explaining this," Dr. Wedemeyer commented.

The study received no commercial financial support. Dr. Gottardi and Dr. Wedemeyer have disclosed no relevant financial relationships.

European Association for the Study of the Liver (EASL) 45th Annual Meeting. Presented April 15, 2010.