A Little Dark Chocolate Goes a Long Way

Study finds half a bar per week lowers heart attack risk

Jacob Gaffney
Posted: September 26, 2008

A new body of research provides good news for hardcore dark chocolate lovers (but bad news for chocaholics): Dark chocolate can reduce the risk of heart attacks, but less is more. The study, published in the latest issue of the Journal of Nutrition, finds that 6.7 grams (0.24 ounces) of chocolate per day is the ideal amount for getting cocoa's antioxidants to protect the heart and blood vessels from inflammation and subsequent cardiovascular disease. That's equal to half a bar per week.

"Maybe time has come to reconsider the Mediterranean diet pyramid and take the dark chocolate off the basket of sweets considered to be bad for our health," said Giovanni de Gaetano, director of the research laboratories of the Catholic University in Campobasso, Italy, where the research was conducted in cooperation with the Nutritional Epidemiology Unit at the National Cancer Institute in Milan. The Mediterranean diet pyramid, popular in Italy, focuses on a high intake of fruit and vegetables with little meat and also includes the regular consumption of wine, preferably red, a glass a day for women and two for men.

For the study, the researchers wanted to determine the ideal amount of daily chocolate consumption needed to lower the level of C-reactive proteins in the bloodstream, a marker of inflammation and coronary heart disease.

By examining the dietary habits of 10,994 people, 34 percent of whom did not eat chocolate and 18 percent who ate only dark chocolate, the type of chocolate believed to be highest in antioxidant polyphenol content, the scientists compared blood samples and rates of heart disease across individual eating patterns.

They found that those who ate small bits of dark chocolate several times a week had 17 percent less C-reactive proteins in their blood, on average, when compared to those who did not eat chocolate. Those who ate more than 6.7 grams per week had around 9 percent less C-reactive proteins. The scientists speculate that the observed effect of cocoa's polyphenols on levels of the proteins likely diminishes the more dark chocolate one eats.

Lead author Romina di Giuseppe added that the benefit is also likely limited to dark chocolate as prior studies demonstrate that, "milk interferes with the body's absorption of polyphenols."

The study also mirrors the promising results of recent research on chocolate and related polyphenols. In one study, published in the American Journal of Clinical Nutrition, subjects assigned to eat 22 grams (0.78 ounces) of cocoa powder daily showed markedly improved blood flow and lower blood pressure than those eating a placebo.

Additionally, recent research published in the British Journal of Nutrition found that rats given an antioxidant extracted from cocoa, the bean used in chocolate making, displayed less brain deterioration related to aging. Commenting on the results of that study, Dr. Curtis Ellison, a professor of medicine and public health at Boston University Medical School, said that, "other studies have shown that dietary supplementation of polyphenolic substances high in antioxidants, e.g. spinach, strawberry and blueberry extracts, tea, wine, may result in improvement in cognitive function. This study adds an extract from cocoa to that list."

"It will be interesting to see if prospective epidemiologic studies show similar benefits among humans," he said.