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.
