Chocolate: A Secret Weapon for your Heart?

Cocoa laden treat provides sweet cardiovascular benefits

/ Author:  / Reviewed by: Joseph V. Madia, MD

There are few among us who can pass up the sweet and decadent taste of chocolate -- at least in moderation. But is your sweet tooth actually giving your heart a boost?

It's well known that eating leafy greens and exercising benefits the cardiovascular system.

However, the thought that chocolate can improve heart health is a much more alluring idea. After all, would you rather spend your Saturday snacking on salad or munching on a candy bar and sipping a warm cup of cocoa?

Hundreds of studies in recent years have shown that the flavanols in cocoa -- chocolate's major ingredient prior to the addition of milk, sugar, butter and other additives in the processing phase -- can provide a benefit to the cardiovascular system.

It's been shown to lower blood pressure, prevent blood clots and improve blood flow.

That doesn't mean all studies have found a benefit -- some haven't and others have been mixed -- but the number identifying a benefit is steadily surpassing research with inconclusive results.

"They've come in both ways, but I think it shows promise. We still have to produce more studies that show cause and effect," said Laura Moore, director of the Dietetic Internship Program of the Michael & Susan Dell Center for Healthy Living at The University of Texas School of Public Health. "(Flavanols) can provide some heart health benefits."

Really? Eat Chocolate?

Flavanols within cocoa have become an increasingly popular research area in recent years. Early findings have identified numerous potential benefits, further peaking the interest of scientists.

Previous research has suggested that flavanols may prevent blood clots by preventing platelets from becoming sticky, while also increasing heart function through a benefit to smooth muscle cells, located in the walls of the heart, Moore noted.

Some studies have suggested the flavanols can help reduce inflammation. Others have suggested that flavanols in chocolate can strengthen mitochondria (cellular organs which produce energy for the body's cells) in patients weakened with type 2 diabetes, helping them to fight cardiovascular disease.

More have suggested flavanols may lower blood pressure, or even help the body regulate insulin delivery to prevent cancer cells from proliferating.

Cocoa has been found in studies to reduce stress and emotional anxiety, and to reduce the risk of developing colon cancer by preventing the development of dangerous cells or by destroying them.

A University of California, San Diego study published in journal Archives of Internal Medicine in March also found that people who eat modest amounts of chocolate on a regular basis tend to be thinner. This was in spite of the fact that regular chocolate consumers were more likely to consume greater quantities of calories and they did not exercise more often.

"Our findings appear to add to a body of information suggesting that the composition of calories, not just the number of them, matters for determining their ultimate impact on weight," said Beatrice Golomb, MD, PhD, associate professor in the department of medicine at the University of California, San Diego. "In the case of chocolate, this is good news – both for those who have a regular chocolate habit, and those who may wish to start one."

Which kind?

Ensuring you're receiving the full benefit chocolate has to offer means you should read labels. Not all chocolate is created equal.

"When you're selecting chocolate for its benefits it's important to read labels and make sure the first ingredient isn't sugar," Moore said, noting that the first ingredient should be listed as cocoa or cocoa mass.

Research also suggests that darker chocolate and cocoa powder tend to have higher flavanol content. Dutch processing is believed to destroy some of the flavanol content, Moore noted.

"It should be unsweetened and natural or unsweetened baking chocolate," said Moore, who suggests incorporating unsweetened baking chocolate into regular dishes by adding it to to savory dishes such as chilies or barbecue sauce, or sprinkling it over baked root vegetables such as beets. "There are a lot of different ways to incorporate it into your diet."

Though it is difficult to truly know the exact amount to consume to benefit the heart, Moore suggests eating one ounce of dark chocolate two to three times a week.

She emphasized using caution about potentially eating too much chocolate in the way of candy bars, which tend to have added fat and sugar and do not provide as many heart benefits. Additionally, she said the evidence of cocoa's heart benefit is not yet conclusive enough to warrant consuming the added calories common in candy bars.

Cocoa solids, the low fat often bitter tasting component of chocolate, also called called cocoa powder, cocoa and cacao, is the better choice for heart health. A general rule of thumb is that the more bitter the cocoa tastes, the higher the flavanol content.

Moore said there have not yet been enough clinical trials to recommend supplements. Studies that have examined them also have found mixed results.

"This doesn't replace fruits and vegetables, which are a high source of flavanols with fewer calories," Moore said. "(Vegetables) also contain healthy compounds like fiber."

Measuring flavanols

One of the major difficulties in determining the benefits of chocolate boils down to methods for measuring flavanols. There has not been a true method to determine amounts of flavanols in various foods, which makes it difficult to compare study results and determine how much should be consumed to offer a protective quality.

"In chocolate there's really no way to measure (the amount of flavanols) so 70 percent from one brand isn't necessarily better than 60 percent from another brand," said Moore.

The recipes used to produce chocolate -- such as the amount of sugar added or the method used to manufacture it -- also can impact flavanol content. But that still doesn't necessarily mean researchers know exact content or can easily compare findings from different studies.

Hoping to nail down those potential positive impacts, Mars, Inc., which produces popular chocolate confections Snickers and M&Ms, recently sponsored research to validate methods for analyzing flavanol content.

Published in late April in Journal of AOAC International, the researchers were able to identify and quantify distinct stereochemical forms of flavanols found in cocoa and chocolate products. Distinct chemical structures of flavanols are believed to influence metabolism, absorption and the subsequent benefits.

For example, one flavanol form is absorbed six times faster than another. Others are only found in foods as a result of the manufacturing process as opposed to occurring naturally. Such findings bring scientists closer to being able to better examine flavanols in trials, and also make meaningful dietary recommendations.

"By clearly identifying the specific stereochemical forms of flavanols in cocoa, this method can help establish stronger connections between cocoa flavanols and cardiovascular health. Our goal was not only to develop a method that could be used by Mars, but instead to validate one that could be widely implemented using standard analytical equipment in order to advance research in this field," commented Dr. Catherine Kwik-Uribe, study author and R&D Director at Mars Botanical.

Review Date: 
May 21, 2012