Sweet Science: The Health Benefits of Chocolate

Dark chocolate contains certain antioxidants called polyphenols that could help fight chronic inflammation of tissues in the circulatory system. Moderate amounts of dark chocolate might also play a role in cancer prevention. (Image credit: Dreamstime)

Yet another health benefit has been linked to eating chocolate: It may decrease your risk of stroke, a new study suggests.

The analysis, which will be presented in April at the American Academy of Neurology's 62nd Annual Meeting, reviewed the results of three previous studies. One study with more than 44,000 participants found that those who ate a weekly serving of chocolate were 22 percent less likely to suffer a stroke than those who ate no chocolate.

The researchers caution however, that more studies are needed to confirm the link, and other factors besides chocolate consumption could be contributing to the decreased stroke risk. Also, one reviewed study showed no connection between stroke risk and chocolate consumption.

Still, the results add to a growing list of potential advantages to eating chocolate, including a decreased risk of cardiovascular disease. But this doesn't mean you should gorge yourself on the candy this Valentine's day either.

Among the pros and cons of chocolate:

Chocolate can be good for you

Many previous studies have linked eating chocolate with health benefits, including:

  • A 2008 study found that people who ate a small amount of dark chocolate a day (about 6.7 grams) had lower levels of a protein that is associated with inflammation in their blood.
  • Other recent studies have found that blood platelets clump together more slowly in chocolate eaters. Clumping platelets can lead to the formation of blood clots, which in turn can cause a heart attack. Chocolate consumption may lower blood pressure, help prevent formation of artery plaques and improve blood flow, according to other research.
  • Eating chocolate may even help with math, or at least counting. A study reported in 2009 showed that people did a better job of counting backwards in groups of three after they had consumed a hot cocoa drink containing large amounts of a compound found in chocolate. These compounds, called flavonoids, which we'll get to later, may increase blood flow to the brain.
  • Chocolate may also have anti-cancer benefits because flavonoids may help reduce the cell damage that can spur tumor growth.   

"More and more research is showing that [eating chocolate] is really more beneficial than we ever imagined," said Katherine Tallmadge a registered dietician and spokesperson for the American Dietetic Association.

However, she notes that the advantages you get still appear to be quite small. "It's not anything major, but it's still an advantage, and even slight advantages can make a difference for some people," she said.

Not all chocolate is created equal

Certain forms of chocolate are better for your health than others, and it comes down to one key component of the rich snack: flavonoids.

These compounds, which are found in the seeds of cacao plants (from which chocolate is made), are antioxidants that are thought to help protect cells against damage that might come from environmental toxins, or simply byproducts of vital processes in the body.

Consuming flavonoids has been linked to heart benefits. But since flavonoids are bitter, most commercial chocolate goes through processing steps that remove these compounds. Less processed, or darker chocolates, will tend to have higher levels of flavonoids. Your best choice in terms of healthiness is to go with natural, unsweetened cocoa powder, Tallmadge said.

"You can have mounds of it," because it is low in calories and full of flavonoids, Tallmadge told LiveScience.

Runners-up for health benefits are bittersweet and semisweet chocolate with a high cocoa percentage, she said. Unfortunately for milk-chocolate lovers, this type of chocolate has lower levels of flavonoids.

Chocolate can be bad for you

The underlying health benefits don't give you an excuse to eat chocolate by the pound.

"Because we mainly eat it as a candy with sugar added, it's going to be high in calories and not necessarily good for you in high quantities, because it will take the place of more nutritious foods," Tallmadge said.

For instance, if you gorge on chocolate, you might skimp out on fruits and vegetables, which are also important for heart health and disease prevention.

Tallmadge advises that people who want to eat chocolate limit themselves to one ounce per day. "Any more than that and you're probably going to take in too many calories for weight control," she said.

Other foods and beverages can also provide flavonoids, including citrus fruits, onions, green tea and red wine.

Rachael Rettner

Rachael is a Live Science contributor, and was a former channel editor and senior writer for Live Science between 2010 and 2022. She has a master's degree in journalism from New York University's Science, Health and Environmental Reporting Program. She also holds a B.S. in molecular biology and an M.S. in biology from the University of California, San Diego. Her work has appeared in Scienceline, The Washington Post and Scientific American.