Small Amounts of Dark Chocolate May Reduce Diabetes Risk

Of course, type 2 diabetes is a complicated condition and chocolate is usually considered a yummy (rather than nutritious) food, so it’s understandable if you feel like the finding is unexpected. Here’s what the research says, plus what could be behind the link.

What did the research find?

The study, which was published in The BMJ on December 4, analyzed data from three long-term studies: the Nurses’ Health Study, the Nurses’ Health Study II, and the Health Professionals Follow-Up Study. As part of these earlier studies, participants answered questionnaires every four years on what they ate, and these surveys continued for 25 years.

In the nearly 192,000 people who said they ate chocolate, the researchers found that those who said they had at least five 1-ounce servings a week of any type of chocolate had a 10 percent lower risk of type 2 diabetes compared to people who said they rarely or never ate chocolate. The researchers had people report their type 2 diabetes diagnosis in future questionnaires, and confirmed their condition through things like glucose concentration, HbA1c (a blood test that measures a person’s average level of blood sugar over the past two to three months), and symptoms and treatments for type 2 diabetes.

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When the researchers drilled down on the types of chocolate people liked, they found that there was no significant drop in diabetes risk for people who said they preferred milk chocolate. However, here’s an even more remarkable finding. People who had at least five 1-ounce servings a week of dark chocolate had a whopping 21 percent lower risk of developing type 2 diabetes. They also didn’t seem to have long-term weight gain over time as compared to their milk chocolate counterparts.

But, doesn’t chocolate raise blood sugar? 

You might be thinking, “Doesn’t chocolate have a lot of sugar?” The quick answer: yes, it can. But, the amount of sugar and the likelihood of chocolate significantly raising your blood sugar levels usually depends on the type of chocolate you eat. “Dark chocolate typically contains more cocoa solids and less sugar compared to milk chocolate,” explains Scott Keatley, R.D., co-owner of Keatley Medical Nutrition Therapy. “This means dark chocolate has a lower glycemic index and is less likely to cause sharp blood sugar spikes.”

Dark chocolate is also higher in cacao, which is the raw form of chocolate, he points out. However, milk chocolate’s higher sugar content and lower amount of cacao can cause “quicker and more pronounced” blood sugar increases, Keatley adds.

There could be something more to this than sugar, though, says Christoph Buettner, M.D., Ph.D., chief of the division of endocrinology at Rutgers Robert Wood Johnson Medical School. “Dark chocolate contains high levels of flavonoids, particularly catechins and epicatechins, which have antioxidant and anti-inflammatory properties,” he says. “These compounds can improve insulin sensitivity, enhance blood flow, and reduce oxidative stress, all of which play a role in reducing the risk factors for type 2 diabetes.”

This isn’t the first study to link smaller amounts of dark chocolate to good health. One study published earlier this year found that dark chocolate was “significantly associated” with a lower risk of high blood pressure. Other research has found that the flavanols (a type of flavonoid) in dark chocolate can help protect against heart disease and may even boost brain performance.

But it’s also worth noting that a randomized controlled trial published in Diabetes Care last year found no impact of consuming cocoa on the risk or prevention of type 2 diabetes. The latest study which found a more significant finding between dark chocolate and diabetes risk also relied on the participants remembering what they ate, which can be fudged or misremembered, Keatley says.

Ultimately, while Dr. Buettner says the latest findings are interesting, he stresses that more research is needed.

The bottom line

While dark chocolate may boast health benefits, including lowering your risk of developing type 2 diabetes, moderation is key. “Dark chocolate is calorie-dense and often contains added sugars and fats, which, when consumed in excess, can contribute to weight gain and increased diabetes risk,” Dr. Buettner explains.

But it’s important to remember that chocolate on its own isn’t going to prevent your chances of experiencing diabetes. “Simply adding dark chocolate to an otherwise unhealthy diet is probably not going to lower anyone’s risk of type 2 diabetes,” says Keri Gans, R.D.N., author of The Small Change Diet. “Consuming an overall well-balanced diet with lots of veggies, healthy fats, adequate protein, and an active lifestyle is more likely to do the trick.”

If you’re worried about your type 2 diabetes risk, our experts recommend focusing on incorporating nutritious foods in your meal plan and making time for exercise regularly. But it’s also good to know that having small, daily amounts of a yummy treat like dark chocolate may do your health a solid, too.