Continued from Page 1

She designed a randomized, placebo-controlled, double-blind study to see what effect high-flavonoid dark chocolate had on blood flow. Eleven lucky subjects ate a 1.6-ounce bar of dark, flavonoid-rich chocolate every day. Ten others ate an identical low-flavonoid bar.

After two weeks, the research team measured the diameter of the subjects’ arteries and discovered a statistically significant improvement in endothelial function — the ability of the artery to dilate and an indicator of vascular health — in those who had eaten the flavonoid-rich chocolate. They also saw an eightfold increase of the chocolate flavonoid, epicatechin, in this group.

The results make sense, Mary says, when you consider that flavonoids found in fruits and vegetables come from plants and so does chocolate, derived from the cocoa bean. Until recently, most chocolate was processed in a way that destroyed from 25% to 50% of its flavonoids. Now some companies are changing the way they process chocolate to preserve as much as 70% to 95% of the flavonoids. Chocolate with 70% or more cocoa content will be high in flavonoids, Mary says.

“I wanted to make sure that (the chocolate study) didn’t come across as frivolous or that this was just another fun study,” she says. “Everything was gold standard, top of the line. I wanted to make sure the science was clearly evident.” The UCSF School of Nursing funded the study, and the American Cocoa Research Association, a trade organization, provided identical high- and low-flavonoid dark-chocolate Dove Bars.

The Englers’ study was the longest one to show improvement in vascular function from eating flavonoid-rich dark chocolate daily over an extended period of time, Mary says. Previous studies showed benefits either after a single dose or several doses of chocolate over a few days, she adds.

A study in Greece, done after the Englers’ study, showed improved blood vessel function for about three hours after subjects ate 100 grams of dark chocolate. That study has led at least one German insurance company to recommend its clients eat small amounts of dark chocolate regularly.

Scientists writing for the British Medical Journal included dark chocolate as part of a “polymeal” that also consists of red wine, fish, fruits and vegetables, garlic, and almonds, and estimate that people who eat these foods every day — with the exception of fish, which they should only eat four days a week — may cut their risk of heart disease by 76%.

Moderation is best

Recommendations on chocolate consumption will not be coming anytime soon from the American Heart Association, says Linda Van Horn, RD, PhD, a professor of preventative medicine at Northwestern University in Chicago and a member of the American Heart Association Nutrition Committee. Van Horn has seen the Englers’ chocolate study and believes it is a good one, but she says much more research on much larger groups of people is needed before chocolate can be recommended as a heart-healthy food. Also, she notes, chocolate is high in calories, contains fat and sugar, and could contribute to obesity if consumed in large amounts.

“No one would suggest that eating chocolate in moderation is a bad thing for you, but we’re not going to go out on a limb and say it’s a good thing for you, either,” she says.

The Englers are quick to emphasize the importance of the “in moderation” aspect of any chocolate-consumption recommendations. “Even though we have a long way to go before we understand all of chocolate’s effects,” Mary says in the press release accompanying the study, “for now, there’s little doubt that in moderation and in conjunction with a healthy, balanced diet and exercise, we can enjoy — and even benefit from — moderate amounts of high-flavonoid dark chocolate.”

The Engers believe flavonoids could eventually prove as beneficial as omega-3 fatty acids have turned out to be. They felt vindicated when European studies came out showing how omega-3 fatty acids benefited the heart and vascular system in many ways. They note that food producers are adding omega-3s to eggs, orange juice, infant formula, and other products, including puppy chow.

In a literature review, published last November in Nutrition Research, the Englers listed studies supporting a variety of vascular benefits from cocoa flavonoids, including antioxidant properties, improvement in endothelial function, lowered blood pressure, decreased platelet activation — which can prevent clotting — and modulation of immune function and inflammation.

“We’re just at the tip of the iceberg with flavonoid research,” Mary says. Current results show a need for larger and more long-term studies on the effects of flavonoids in chocolate, cocoa, and other foods and beverages, she says.

“We have our research cut out for us for a number of years,” notes Marguerite.

Besides the chocolate studies, the Englers have recently published studies, with Marguerite as the lead author, showing how antioxidant vitamins C and E and the omega-3 fatty acid DHA improve endothelial function in children with high cholesterol. They have a grant from National Institute for Nursing Research to look at early nutritional interventions in children who have a family history or other risk markers for heart disease.

The Englers’ work and the public attention it has received are inspiring to students and other nurse researchers, Dracup says. “We welcome that attention to nursing research,” she adds. “In their research, nurses are usually not discovering the cause of diseases or a new form of intervention.” Most nursing research focuses on symptom management, reducing risk factors, and managing chronic illness. “That’s not the stuff of high drama.”

The Englers say they have always been chocolate connoisseurs, though Mary says she has converted to eating dark instead of milk chocolate as a result of the study. Marguerite has always preferred dark chocolate. When they were in high school, their favorite candy was, naturally, M&M’s. They even dressed as M&M’s one Halloween. Mary was plain; Marguerite was peanut.

“Who’d have predicted,” says Mary, “that years later we’d be doing a chocolate study.”

And finding out that, at least in moderation, it may actually be good for you.

Cathryn Domrose is a staff writer for NurseWeek.

To comment on this story, send an e-mail to editorca@nurseweek.com.