Published October 01, 2005
Chocolate may help repair damage to smokers’ blood vessels, at least temporarily, a new study shows.
The benefit may stem from antioxidants called flavonols that are found in chocolate (and fruits and vegetables), write the researchers in the Journal of the American College of Cardiology.
But smokers shouldn’t count on chocolate for heart health. The best bet is to quit smoking, states a news release from the American College of Cardiology.
The study was done by researchers including Christian Heiss, MD, PhD, of Heinrich-Heine University in Dusseldorf, Germany.
Only 11 people participated. They were about 31 years old, on average. All were smokers, and smoking was their only known risk factor for heart disease.
Smoking raises the risk of many health problems, including heart disease, which is a leading cause of death for men and women alike.
Why weren’t any nonsmokers included? Smokers tend to have abnormal blood vessel responses to blood flow. Those abnormalities are what the researchers were interested in.
Those abnormalities are called endothelial dysfunction. That means that blood vessels had trouble expanding or contracting to handle changes in blood flow. Endothelial dysfunction can lead to atherosclerosis (the hardening of the arteries), which could eventually cause a heart attack or stroke.
Smokers aren’t the only people who can have endothelial dysfunction.
Participants were told to fast overnight and not smoke for 12 hours before the experiment. Each person drank a flavonol-rich cocoa drink and a flavonol-poor cocoa drink. The two drinks looked and tasted the same.
Blood vessel function was notably better after drinking the flavonol-rich drink, the researchers report. That might be due to rises in levels of a chemical called nitric oxide in the blood, they write.
When participants were given a drug to block nitric oxide, no further improvements were seen.
Long-term effects of chocolate on endothelial dysfunction aren’t known.
The study was funded by an unrestricted grant from candy maker Mars Inc., which also supplied the cocoa drinks.
Besides chocolate, flavonols are “abundantly present in fruits and vegetables,” write the researchers.
Flavonols belong to a family of antioxidants called flavonoids. Flavonoid sources include red wine, tea, and produce including sweet cherries, apples, apricots, purple grapes, blackberries, raspberries, and broad beans.
The cocoa drink used in the study was specially processed to retain much higher flavonol levels than those typically found in commercially available cocoa drinks, so “it is unlikely that drinking more hot chocolate would produce a similar effect,” states the American College of Cardiology’s news release.
Tempted to flock to chocolate for heart health? You might want to nibble, not gorge. Overdo it, and you may blow your calorie budget and gain weight, which could further burden your heart.
SOURCES: Heiss, C. Journal of the American College of Cardiology, Oct. 4, 2005; vol 46: pp 1276-1283. News release, American College of Cardiology.